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Mars Sample Return backward contamination – Strategic advice and requirements Report from the ESF-ESSC Study Group on MSR Requirements European Foundation (ESF) European Space Sciences Committee (ESSC) The European Science Foundation (ESF) is an The European Space Sciences Committee (ESSC), independent, non-governmental organisation, the established in 1975, grew from the need to give members of which are 72 national funding agencies, European space scientists a voice in the space arena research performing agencies and academies from 30 at a time when successive US space science missions countries. and NASA’s Apollo missions dominated space The strength of ESF lies in its influential membership research. More than 35 years later, the ESSC actively and in its ability to bring together the different domains collaborates with the (ESA), of European science in order to meet the challenges of the European Commission, national space agencies the future. and the ESF Member Organisations. This has made Since its establishment in 1974, ESF, which has its ESSC a reference name in space sciences within headquarters in Strasbourg with offices in Brussels . and Ostend, has assembled a host of organisations The mission of the ESSC today is to provide an that span all disciplines of science, to create a independent forum for scientists to debate space common platform for cross-border cooperation in sciences issues. The ESSC is represented ex officio Europe. in all ESA’s scientific advisory bodies, in ESA’s High- ESF is dedicated to promoting collaboration in level Science Policy Advisory Committee advising scientific research and in funding of research and its Director General, it has members in the EC’s FP7 science policy across Europe. Through its activities space advisory group, and it has observer status in and instruments, ESF has made major contributions to ESA’s Ministerial Council. At the international level, science in a global context. ESF covers the following ESSC maintains strong relationships with the National scientific domains: Humanities, , and Research Council’s (NRC) Space Studies Board in the Environmental Sciences, Medical Sciences, Physical US. and Engineering Sciences, Social Sciences, Marine The ESSC is the European Science Foundation’s (ESF) Sciences, Materials Science and Engineering, Nuclear Expert Committee on space sciences and the ESF’s Physics, Polar Sciences, , Space interface with the European space community. Sciences. www.esf.org/essc www.esf.org

The European Science Foundation hosts six Expert Authors Boards and Committees: Walter Ammann, John Baross, Allan Bennett, • The European Space Sciences Committee (ESSC) Jim Bridges, Joseph Fragola, Armel Kerrest, • The Nuclear Physics European Collaboration Karina Marshall-Bowman, Hervé Raoul, Petra Rettberg, Committee (NuPECC) John Rummel, Mika Salminen, Erko Stackebrandt, • The Marine Board-ESF (MB-ESF) Nicolas Walter • The European Polar Board (EPB) • The Committee on Radio Astronomy Frequencies (CRAF) ESF Support Staff • The Materials Science and Engineering Expert Committee (MatSEEC) Nicolas Walter, Senior Science Officer Karina Marshall-Bowman, Junior Science Officer In the statutory review of the Expert Boards Johanne Martinez-Schmitt, Administrator and Committees conducted in 2011, the Review Panel concluded unanimously that all Boards and Committees provide multidisciplinary scientific Contact services in the European and in some cases global framework that are indispensable for Europe’s Nicolas Walter scientific landscape, and therefore confirmed the need Senior Science Officer for their continuation. Physical, Engineering and Space Sciences Unit The largely autonomous Expert Boards and Tel: +33 (0)3 88 76 71 66 Committees are vitally important to provide in-depth Email: [email protected] and focused scientific expertise, targeted scientific and policy advice, and to initiate strategic developments in areas of research, infrastructure, environment and society in Europe.

Cover picture: ISBN: 978-2-918428-67-1 European Space Agency Printing: Ireg – Strasbourg September 2012 Contents

Foreword: Mission Statement 3

1. Sample Return Mission and planetary protection – background 5 1.1 Planetary protection regulatory framework 5 1.2 Mars Sample Return Mission concept 6 1.3 Sterilisation: concept, methods and limitations 7 1.4 Summary of advice from past committees 9

2. From remote exploration to returning samples 10 2.1 New missions for new knowledge 10 2.2 The importance of not compromising the sample and the Mars surface 11 2.3 The challenge raised by a returned sample 11 2.4 Considering backward contamination through particle size 12

3. Life as we know it and size limits 14 3.1 Life as we know it 14 3.2 Approaching the issue of minimum size limit for life 14 3.3 Characteristics of the smallest cells 15 3.4 17 3.5 Gene transfer agents (GTAs) 18 3.6 From new knowledge to new requirements 19 3.7 Perspectives for the future 21

4. Defining the adequate level of assurance for a non-release 22 4.1 From risk to level of assurance 22 4.2 Approaching the unknown and considering consequences 22 4.3 The Precautionary Principle in the context of MSR 25 4.4 Emission optimisation strategies 25 4.5 Quantitative risk levels used by regulators 27 4.6 Updating the appropriate level of assurance 31 4.7 Potential verification methods 32 5. From release to risk: a framework to approach the consequences 33 5.1 The sequence of events leading to environmental consequences 33 5.2 Estimate of the overall risk 35 5.3 Direct consequences for human health 35 5.4 Being prepared 38

6. Perceived risk: differences between the general public and experts 39

7. Regulatory and legal aspects of a Mars Sample Return Mission 42 7.1 Obligation to prevent pollution/contamination of and the Earth 42 7.2 Responsibility and liability of States 43 7.3 The necessity/utility to give some legal value to measures preventing damage 44

8. Study Group findings and recommendations 45 8.1 Mars exploration and sample return 45 8.2 Uncertainties, Precautionary Principle and optimisation 45 8.3 On particle size 46 8.4 Public perception 47 8.5 On the required level of assurance 47 8.6 Implication for design 48 8.7 Accompanying measures 48

References 50

Annex 1: ESF-ESSC Study Group composition 57 Annex 2: Risk perception workshop – participation, consensus statements and recommendations 58 12 high-level, international and multidisciplinary multidisciplinary and international 12 high-level, As planetary protection regulations have protection regulations asignifi planetary As MSR mission. ESF commissioned a study group commissioned astudy of ESF mission. MSR Return (MSR) mission. Specifically, ESF was asked ESF was (MSR) Specifically, mission. Return Environmental Sciences (LESC), Medical Research Research Medical (LESC), Sciences Environmental (SCH). Sciences (PESC) (EMRC), Physical Engineering and l l l Statement Mission Foreword: Committee (ESSC) to perform a study regarding regarding to astudy (ESSC) perform Committee implemented with proper justification and areand implemented properre- with justification preventing an unintended release of Martial par release of Martial unintended preventing an provide new insights and recommendationsprovide and where new insights forSample protection aMars regulations planetary organisations in Europe and beyond as well as to as beyond well and Europe as in organisations overall cost, it is critical that the guidelines are guidelines the that it critical cost, is overall to perform a study on the level of assurance of level onto the perform ofa study assurance the ESF standing committees on Life, Earth and and Earth on Life, committees standing ESF the tion) to requirements, current and to the evaluate of an frame the in Earth’s intothe ticles applicable. Group The Study formed was following as well as Social Sciences (SCSS) and Humanities Sciences (SCSS) Humanities Social and as well as to severalresearch addressed for nominations a call Science Foundation (ESF) in asked European the experts (see 1 forGroup Study experts composi Annex basis. onevaluated aregular coordination with its European Space Sciences itsEuropean with coordination and engineering design, on mission impact cant In June 2011,In Space Agency European the - - - “Recommend the level of assurance for the exclu for the levelof assurance the “Recommend 1999). However, shown enor has decade past the Workshop’, 0.25 that ±0,05 declared which various environments. Therefore, environments. thethe various for value Earth environment shall be less than 10 shall be less environment Earth 2012. The outcomeand fromthe recommendations 2011 of awork organisation commissioned the and were used as direct inputs in the formulation of the of formulation the the inputsin were direct as used we as it know (NRC, for life lower the was limit size Sample Return mission”. Return Sample in this report. Also, the current level of assurance level current of the assurance Also, report. this in of 0.2 micron diameter or greater is released into the released is greater or diameter micron of 0.2 derived from the NRC-SSB 1999 report ‘Size Limits derived 1999 Limits from report NRC-SSB the ‘Size maximum particle size that could be released could into that size particle maximum mous advances in ,mous advances in microbes in and on three occasions between June and November June and occasions between on three recon is of preventing release particle of the aMars of a Proceedings : of Small the Earth’s biosphere revisited is re-evaluated Earth’s and the particle ‘the that unsterilised probability asingle that: the 0.10–0,15the risk perceptionrisk workshop (see 2 for details) Annex requirement used since the late 1990s specifying requirement late the 1990s since used specifying advice contained in this report. this advice in contained life form into the Earth’s biosphere for a Mars biosphere for aMars Earth’s the into form life shop to dedicated perceptionrisk January held in sidered. sion of an unintended release of a potential Mars Mars of apotential release unintended sion of an The mandate of the Study theGroup Study of The mandate to: was The value for the maximum particle size was size particle the maximum The for value The starting point of this activity was the was activity pointof this starting The To complete Group Study the its met mandate, µm range have range µm been discovered in 6 ’. µm µm - - - -

Mars Sample Return backward contamination – Strategic advice and requirements 3

1.1 In 1967,In United the Nation’s l l l background – protection planetary and SampleMars Return Mission 1. Currently, treaty, to the over 100 party are countries framework ing that: that: ing defined the grounds for planetary protection,stat forthegrounds planetary defined maintains and propagates this planetary protection planetary propagates and this maintains and the Committee on (COSPAR) Space Research Committee the and “parties to the Treaty shall pursue studies of Outer of Outer to the Treaty studies shall pursue “parties Planetary protection regulatory protection regulatory Planetary Space, including the and other celestial bod celestial other the Moon and including Space, and, where necessary, shall adopt appropriate appropriate shall adopt necessary, where and, their harmful contamination and also adverse adverse also and contamination harmful their changes in the environment of the Earth resulting resulting of the Earth changes the in environment ies, and conduct exploration of them so as to avoid to avoid as of so them exploration conduct and ies, from the introduction of extra-terrestrial matter matter extra-terrestrial of introduction the from (United Nations, 1967). 1967). Nations, (United purpose” this for measures - - Earth to other celestial bodies, whereas bodies, to celestial other organisms Earth Forward contamination refersForward of contamination introduction to the COSPAR has identified COSPARfive identified has categories of space ing nations. ing interest for the study of chemical ofinterest chemical and/ forstudy the policy, while also providing guidelines to spacefar guidelines providing also policy, while mission depending on the target body, target on the its potential depending mission (i.e.mission lander, flyby,mission). or sample return or origin of life and the type of mission (e.g. direct of(e.g. mission direct type the and of life or origin of and/orof evolution, type life the chemical and targeted body and its significance to the origin the origin to its significance and body targeted tamination: forward and backward contamination. contamination. backward and forward tamination: backward contamination refers contamination backward release to of the adapted for specific missions, depending on the on depending missions, adapted for specific extra-terrestrial material into the Earth’s biosphere. Earth’s into the material extra-terrestrial contact, Earth return) with suggested planetary planetary suggested return) with Earth contact, Planetary protection of con considers types Planetary two Planetary protection regulations are further protectionfurther are regulations Planetary Credit: NASA/JPL-Caltech life. microbial sustain to ability present or past Mars’ investigate will rover Science Laboratory Figure 1. NASA’s Mars NASA’s Mars - -

Mars Sample Return backward contamination – Strategic advice and requirements 5 Mars Sample Return backward contamination – Strategic advice and requirements 6 • 1.2 Mars surface (Mars Vehicle). Ascend surface Mars pro Planetary Earth Entry Vehicle one Entry fetch rover and the for both Earth Figure Figure 2 Category I (no requirements) to Category IV (more IV (no I Category to requirements) Category for the caching mission, one orbiter/ mission, for MSR the for caching the particular is divided into three subcategories: into three divided is particular (one from Earth launches maythree mission include fromprotection requirements for ranging each, tection regulations will address both forward and and forward both address will tection regulations most requirements)the (COSPAR, 2002–2011). backward contamination during this mission; the the mission; this during contamination backward requirements for Mars missions; category IV in in IV category missions; Mars for requirements report focus on the latter. on the report focus missions – return restrictive), V(Earth Category and activity of the ESF-ESSC Study Group and this Group Study this and ESF-ESSC of the activity Vehicle) Ascend Mars and from one the and launch concept sible Mars Sample Return (MSR) The mission. sible Sample Return Mars Category IVa. Lander systems not carrying instru not carrying systems IVa.Category Lander ments for the investigations of extant Martian life, Martian ments of forinvestigations extant the COSPAR defined specific category III/IV/V category COSPAR specific defined Mars Sample Return Mission Mission Return Sample Mars : An example of a possible Mars Sample Return mission architecture mission Return Sample Mars apossible of example : An

2 depicts the mission architecture of a pos architecture mission 2 depicts the descent Sky Crane Mission Caching deposits cache rover Caching Orbiter MSR Cache retrieves cache rover Fetch descent Crane Sky EARTH SURFACE MARS SURFACEMARS Lander MSR 500 km orbit km 500 Time - - - • • • The concern, however,theThe main potential in lies - Vmis regarded is aCategory mission as MSR An ward contamination requirementsward to contamination avoid not only for on-going and future life-detection experiments. experiments. life-detection for future on-going and portion of the mission must meet Category IVb for IVb meet must Category mission of the portion designed system alander considering ments. When to investigate extant Mars life, the outbound the life, Mars to extant investigate by Mars material through the Earth Entry Vehicle Entry Earth the through material by Mars biosphere Earth’s of the contamination backward and the sample it contains. COSPAR sample recommends it the contains. and having the highest planetary protection require planetary highest the having strict requirements (Categorystrict V), including: sion with restricted Earth return, this category this return, restricted Earth sion with contamination but also false positive indications positive indications false but also contamination Unless the samples to be returned from Mars are Mars from to be returned the samples Unless Martian special regions. special Martian Category IVc.Category For investigate which missions to designed For systems lander IVb. Category verification process, and the samples shall remain shall remain samples and the process, verification investigate extant Martian life, Martian investigate extant contained during all mission phases through trans phases mission all during contained the canister(s) returned the samples holding process, subjected to an accepted and approved sterilisation sterilisation approved and to accepted an subjected from Mars shall be closed, with an appropriate withappropriate an shall be Mars closed, from contingency sample collects Lander (MAV) Vehicle Ascent Mars and capture of OS of capture and Rendezvous (OS) Orbiting Sample Vehicle (EEV) Entry Earth Facility (SRF) Facility Sample Receiving system containment Verify flight of ERV divert Earth - - - • • • 1.3 11139: to aterm any referring is Sterilisation 2006). Tests pro theefficiency of sterilisation to confirm viable (micro-)organisms (adapted from ISO/TS years the term has evolved to also include the disa evolvedthe term has include the years to also we know it with awater-mediatedwe it know with chemistry. However, for years that many it been known has Sterility is defined as the state of being freefrom the state as of being defined is Sterility from a whole microbial community presentfrom a a whole in microbial community fungi, , viruses, etc.) forms, present viruses, bacteria, fungi, indicate viability, but lack of growth on or in media media on but or in lack of viability, growth indicate inside or afluid, in contained or on asurface, air in nation. Thus culturability is a parameter which can can which is a parameter culturability Thus nation. does not indicate the absence of cells or cell death. death. or cell absence the of notdoes cells indicate magnitude between the numbers of cells from natu numbers of cells the between magnitude phenomenon been observed by had other already prions. recent In rocks. certain as such porous materials forms of micro all or kills process eliminates that only a very small portion of all microorganisms microorganisms of all portion small avery only the first time by Staley and Konopka time by Staley first the (1985),the but for used was greatterm “the plate count anomaly” bling or destruction of infectious such as proteins as such of infectious or destruction bling (such agents transmissible as including life, bial ral environments that form colonies on agar media environments form media ral that colonies on agar and the numbers countable by countable microscopic numbers exami the and scientists. It describes the difference in orders of difference It the describes scientists. certain environment can be grown in the lab. The the environment begrown in can certain assays. cultivation performed are cesses as routinely methods and limitations and methods The mission and the design must provide provide must design spacecraft and the mission The Mars, and any inflight transfer operations required required operations transfer inflight any and Mars, - environ hardware of such Mars the from Isolation Earth re-entry. Earth Reviews and approval of the continuation of the of the approval continuation and Reviews For unsterilised samples returned to Earth, apro to Earth, returned samples For unsterilised No uncontained hardware that contacted Mars, Mars, contacted that hardware uncontained No - distribu the controlled for absolute precondition an with Mars. the chain of contact” to “break a method gramme of life detection and biohazard testing, or a a or testing, biohazard and of life detection gramme loading into the containment system, launch from from launch system, into the containment loading for return to Earth; and 3) prior to commitment to 3) to and commitment to Earth; prior return for by the mission. by tion of any portion of the sample. of portion any tion directly or indirectly, shall be returned to Earth. to Earth. shall indirectly, be returned or directly proven sterilisation process, shall be undertaken as as shall be undertaken process, sterilisation proven Mars leaving Earth; to from prior 2) to launch prior containment. under opened it (they) where facility to a receiving port be can ment shall be provided during sample container container sample during shall be provided ment flight mission shall at stages: be three required mission flight 1) Sterilisation procedures developed are as Sterilisation for life Sterilisation: concept, concept, Sterilisation: ------There are differentThereare many microorgan reasons why Viking Mars landers, which were built and launched launched and were which built landers, Mars Viking Each of these methods has advantages and limita advantages and has methods of these Each (DHMR) process. This technique was used on the used on was technique process. This (DHMR) -mediated many carbon-based If we expect life as we it know as (Chapter life we expect If 3.1) a with iii. ii. i. not do isms grow laboratory conditions: under in the 1970s. However, the in elec advanced materials, niques may have on the to be applied depending necessary to determine whether microorganisms, microorganisms, whether to determine necessary nucleic acids to detect and quantify ribosomal and and ribosomal nucleic quantify toand detect acids pH. However, questions scientific isit for certain messenger RNA, or the measurement of enzymatic measurement or the of enzymatic messenger RNA, metabolically active, even if they cannot be cul cannot even active, they if metabolically of the sterilisation techniques mentioned techniques above sterilisation of the on spacecraft componentssystems. and tured. Different molecular-based methods can be can Different molecular-based methods tured. compositionto , gas nutrients, and are which experiments on based growth are tion used on spacecraft today could be damaged bydamaged on be spacecraftused today could heat-sensitive other and tronics, equipment being have which tions to be considered before choosing potential, membrane integrity, of membrane tion rently have one approved only of method spacecraft a method for a method purpose. aspecific alternative sterilisation methods for application application for methods sterilisation alternative applied for the investigation of different biological applied biological of forinvestigation different the actual assumptions about putative Mars life forms. about forms. putative assumptions life Mars actual respiration. demonstrate to activities vitro in the proteinand synthesis, application of fluorescentinvestigadyesthe for endpoints (Rochelle endpoints (Rochelle e.g. in an environmental sample, are viable are sample, and environmental an in e.g. sterile and the applicationfor the sterilisa of and methods sterile space agencies are developing and standardising space agencies standardising developing are and treatment. high-temperature Therefore,such both heat reduction microbial dry –the sterilisation conducted under defined conditions with with respect conditions conducted defined under cal, chemical or mechanical methods (see methods Box 1). or mechanical chemical cal,

Therefore being thestatement of something For an MSR mission other sterilisation tech sterilisation other mission For MSR an cur NASA and protection ESA For planetary they are dead, are they the organisms can be cultivated but be cultivated have can organisms the need conditions which they environmental Sterilisation processes can be divided into physi processes be divided can Sterilisation osmotic stress, etc.). stress, osmotic or compounds fac physical chemical of specific tors, need for organisms, other toxic metals, UV light, biocides, starvation, biocides, starvation, light, UV toxic metals, tivable) aresponse state as to (antibiotics, stress entered (viabletransiently aVBNC but not cul have not yet been reproduced laboratories, in e.g. extremely long incubation times, necessity necessity times, incubation long extremely e.g. et al. et , 2011). are the Examples amplification of of amplification ------

Mars Sample Return backward contamination – Strategic advice and requirements 7 Mars Sample Return backward contamination – Strategic advice and requirements 8 • Ionising sterilisation Radiation sterilisation heat • Dry sterilisation • Steam water. of presence the and dependent time is upon degree of exposure the heat, the microorganisms inactivate which iswith heat able to efficiency The be applied only to Itthermostable materials. can method. sterilisation It abulk is of reliable method sterilisation. and used most widely the is Heat sterilisation sterilisation Heat Physical methods 1.Box Sterilisation processes • Filtration Mechanical methods chemicals liquid with • Sterilisation • Gas sterilisation vapour • Chemical Chemical methods radiation • UV matrix of the filter material. filter of the matrix the within trapping and adsorption filtration are sieving, of Themajor mechanisms viable particles. it capable is as non- viable and gases of of both and preventing passage the of liquids sterilisation and not does Filtration destroy but clarification the removes for It used both is microorganisms. the solution. aqueous an in immersible be the devices thatmust is sterilisation of method this disadvantage of pathways. The biochemical vital impair and enzymes essential may and oxidise walls of cell rupture the through transportation membrane interferecell with also and may andin enzymes proteins bonds disrupt They devices. medical peracetic acid as or such peroxideChemicals solutions for used are sterilising effective surfaces. on only are plasmas Gas time. exposure the and mixture gas gas or the source, plasma the of and type energy the on depends efficiency The . These take and place reactions at moderateexcited . radicals atoms , and Cold by atmospheric complex microorganisms reactions plasma inactivates induced gas by chemical surfaces. effective are on only They and/or and carcinogenic and mutagenic corrosive.toxic are potentially gases These oxidative damage. components proteins nucleic Hydrogen as and such acids. peroxide induces cellular reactionstion with by alkyla activity reactive biocidal as oxide and possess such gases Chemically objects difficult. application dimensional the on and three dosimetry the makes which effective onsurfaces, It only is of DNA dueinduction to damage. the germicidal is radiation UVC be applied toonly radiation-resistant materials. (X-rays, radiation of the energy and β radiation). γ radiation, type on It the depends can tion depth components. The penetra cellular other DNA in and in damage induces radiation Ionising method. sterilisation It a bulk is devices. of medical for sterilisation routinely used is radiation the Ionising sterilisation. for steam than temperatures necessary are Higher sensitive materials. damage can Humidity

plasma

radiation

sterilisation

sterilisation - - 1.4 MSR mission. The is reader mission. MSR recommended to refer Recommendations’ (NRC, 1997). (NRC, Recommendations’ The key recom (NRC, 2009): (NRC, only to not 2007a), it(NRC, then may bedifficult NASA to re-evaluate recommendations produced produced recommendations re-evaluate to NASA In orderIn not to re-invent Table wheel, the 1presents efforts have significant that to recognise It crucial is Figure Studies Board (NRC-SSB) commissioned Board by was Studies key reports regarding planetary protection for an planetary key reports regarding in the 1997 report ‘Mars Sample Return: Issues and and Issues 1997 the report Sample‘Mars in Return: detect forms, but also to ensure but forms, also life extraterrestrial detect mission, the National Research Council Space Council Research National the mission, mendations from the 2009 re-evaluation include include re-evaluation 2009 the from mendations performed regarding future sample return missions. missions. sample return future performed regarding on issues not presented or discussed thoroughly in in on not issues thoroughly presented or discussed for carbon scaffolding elementon than an other this report. this to the included documents for further discussion discussion for further documents included to the etary protection, considerable and etary research been has on based asolvent watere.g. or based than other sterilisation. could be utilised. If we expect other forms of life, forms other of we life, expect If be utilised. could past committees past gone for policies plan current into developing the Due toDue recently re-ignited MSR an interest in Summary of advice from from of advice Summary 3. The Viking I spacecraft in a clean room. room. aclean in Ispacecraft Viking The Credit: NASA - - • • Sample Return mission background 1. Important documents regardingTable a Mars “No uncontained Mars materials, including space including materials, Mars uncontained “No be should spacecraft by Mars from returned “Samples Policies Background Category Return Sample Mars ous until proven otherwise” proven until ous hazard though potentially as treated and contained craft surfaces that have been exposed to the Mars to Mars the exposed that been have surfaces craft sterilised” environment should be returned to Earth unless unless to Earth be returned should environment • COSPAR, COSPAR Planetary Planetary COSPAR • COSPAR, Principles on Treaty Nations, • United Report • National Research Council, Assessment Assessment Council, Research • National an for Planning Preliminary • iMARS, An Council, Research • National Council, Research • National 2002–2011). 24, 2011 March and (COSPAR, 2008, 20, July 24, 2005, March amended as 2002, Policy, 20October Protection 1967). Nations, 1967 (United Bodies, Celestial Other and Moon the Including Space, Outer of Use and Exploration the in States of Activities the Governing (NRC, 2009). (NRC, 2009 Missions, Return Sample Mars for Requirements Protection Planetary of 2008). (iMARS, 2008 Mission, International Sample Return Mars 2007b). (NRC, 2007 Mars, of Exploration Strategy for the Recommendations, 1997 (NRC, 1997). SampleMars Return: Issues and - -

Mars Sample Return backward contamination – Strategic advice and requirements 9 10 Mars Sample Return backward contamination – Strategic advice and requirements An image taken by the Rover of the Mars surface. surface. Mars the of Rover Spirit the by taken image An 4. Figure for search the in and system, solar our in planet most Earth-like the of Mars, interest in growth yearsfifteen an enormous The past have shown • • notare restrictedto): includefew examples of (but overarchingbenefits a vast; are exploration sample of return aMars and TheMars benefits general public. of the but also benefits vast forsciencenotand only technology, however, attention to elucidate requires the extra mission, investmentthe A sample return made. involved andformedrisks benefits on the to justify mustbe per For analysis space an any mission, 2.1 l l l to returning samples From exploration remote 2. • • • • always led to future discoveries ledalways to future sciencediscoveryof has history thatshows The exploration human future to pave knowledge wayGathering the for potential life extra-terrestrial discovering of possibility The of mankind destiny of the part as discovery Exploration and exploration space engagement excitement and Public science in and Improving the picture of a ‘larger world’ of a‘larger picture the Improving New missions for new knowledge New missions Credit: NASA - Combining data collected by the numerous by the orbital collected data Combining 2012). August in to land –scheduled Curiosity and rovers four and (Sojourner, , Spirit, and ), (Mars landers Pathfinder successful Orbiter), Reconnaissance Mars and Express two orbiters (Mars Surveyor, Odyssey, Global Mars Mars 1997,Since Mars there have successful been four life. or extinct environments amenable for extant tory of Mars, its volatiles and climate, its geological itsgeological climate, and itsvolatiles of Mars, tory - his the great make could progress understanding in the of asample, study researchers 2008). Through iMARS, 2007; ISECG, 2006; questions (e.g. ESA, high-priorityanswering fundamental, scientific conveyed and mission, MSR of an its in necessity have importance research the and councils declared space from reports Several international agencies a wholeas (McCoy, Herd, and 2011). Corrigan of Mars understanding the advances in dramatic exploration, it promise Mars as would in priority est life. of possibility phere, water, evidence for past abundant the and atmos- a scant of with planet be painted a rocky can of over , studies apicture Mars 50 tory fromdata labora with and spacecraft landed and A Mars sample return has been deemed has high the sample A return Mars - - of Earth organisms entering the sample. COSPAR sample. the entering organisms of Earth possibility the reduction prior to minimise to launch bioload significant undergo must systems dling han sample and acquisition All organisms. Earth and Mars between distinguish to bedifficult tially research poten it done could as sample, on the all of the validity affect would Contamination mised. not are planet on compro the science experiments life future that to ensure important extremely is life by Earth from contamination forward Mars From point of astrobiological view, an protecting surface Mars the and sample the compromising 2.2 ’, 2007b). pp. 73–77 (NRC, for the ‘An Strategy report, Astrobiology Council’s towardsNationalResearch reader the directed is vs. ofsample return a Mars pros on the cons and discussion For afull kind. accomplishment of man prestigepride to this and engagement to space-related with along activities, enormous excitement public bring and sample will aMars above to the returning addition points, In • • • desirable 2007b): for several reasons (NRC, is asample to Earth returning surface, Mars the through 2007b). (NRC, ration to Mars missions explo precursor tohuman any essential deemed an been also has astrobiology. sample return AMars into new insights geophysicaland gain history, and • • • • • The ability to repeat experiments in multiple lab in tomultiple repeatexperiments The ability they are discovered are they if theto There potential propagateis organisms possible Participation of entire analytical community is Earth is on available oratorieskey results confirm and beapplied on Earth can that techniques analytical of range unlimited almost an and instruments There available amuch is greater in diversity emergencies with to deal ability the impedes which Mars, delay to communication Thereis a significant beflown can that ofweight instrumentation and with regard to size Therearelimitations major measurements new and protocols,via experiments discoveries unexpected and unknown the with ing deal in for flexibility asample allows Returning betoo complex situ in for an will sample preparations their and experiments Many Although some questions may be answered Although The importance of not The importance in situ in studies carried out by carried robotics on studies in situ in robotic mission robotic analysis, the analysis, ------• outbound leg) (COSPAR, 2002–2011): (required for the IVb for category that stating lines, implementedhas guide contamination forward Figure be an even greater hazard for Mars organisms: it has it even has greaterbe an fororganisms: hazard Mars atmospherewet). may FreeEarth’s the in and warm (largely most environments on Earth fromenvironment (cold different very is dry) and even itThe Mars if were done on purpose. being to accomplish difficult be very would organisms, of or Mars apopulation fromsible Mars, of apos - introduction the that It be clear should a returned sample 2.3 see where improvements bemade. can lessons and learned to understand guidelines tection pro planetary strict with spacereview past missions Mars of Contamination report Forward Preventing the Council’s Research readerthe encouraged to is refer National to the and report, scope of the this ment not is within environ ofMars Forward the contamination determination protection for purposes planetary • OR ments experi life-detection particular of the sensitivity of bioburden and reduction by driven the face bioburden level of ≤30 , or to levels is systemsur to a restricted landed entire The material to be analysed is in place. in is to beanalysed material of the contamination the and subsystems sterilised ofa method preventing of recontamination the and levels, to these be sterilised must detection of samples for used life delivery, analysis tion, and involvedare thewhich acquisi in subsystems The The challenge raised by raised The challenge 5. Microbial sampling of for a bioburden spacecraft

(NRC, 2006). One may also One may also 2006). (NRC, . Credit: DLR . Credit: ------11 Mars Sample Return backward contamination – Strategic advice and requirements 12 Mars Sample Return backward contamination – Strategic advice and requirements large impact events across the history of the solar solar of the events impact large across history the of aresult as perpetuated Earth, and Mars between of interchange materials natural possible the that (2000) it is that are al. et cations of Mileikowsky impli the ofprovide safety. Indeed, guarantee any 2009). (NRC, that to pathogenic humans” are of life forms examples any have yielded not yet Earth on environments that low.”noted “extremealso The very report being regarded still as is samples Mars of pristine quantities small of fromthe release arising pathogenic effects large-scale for potential “the that 2009 cluded in appreciated 1997, in con Board Space Studies the was than interchanges more for frequent potential of the Even understanding now, expanded an with 1997). (NRC, however” zero, is not risk The effects. harmful significant other or impact ecological cant of signifi arisk to pose unlikely is microorganisms Mars putative by of Earth “contamination the that concluded 1997 Board in Space Studies Council’s US Research National the bly on inhabitable Mars, compared possi are that to those onniches Earth the available between given inherentdifferences the and its possibility, acknowledging still while tact, one at on all. Mars ,there proves indeed, if, planetary to be on recent any contacttwo limitations the between al. et (e.g. Mileikowsky to Mars from Earth of interchange materials natural the the early face in potential of in Even 1970s. craft exploration of Mars by robotic space beginning the microbes have since trip the made ofnumber Earth alimited only and Mars, and Earth between tact con have regular macro-organisms other been in or no humans that It certain quite is organisms. parasites of be obligate Earth would exist, they if one. than invasion of formuch success is an less such ability prob the certainly and microbe, Mars invading an for daunting are Earth the lenges of contaminating hazard)potential becomes even lower.chal The microbe (and alien its for an for survival chances the organisms, of competitive predatory and Earth the presence thosewaytheir Adding places. to find would organisms Mars that chance a limited only is but there someenvironments, anoxic, are of which have does anaerobic cold dry and organisms). Earth wiped out years ago lion most Earth’s of early the (the Great Event Oxygenation 2.4 bil around to producenot antioxidants developed ability the therefore is and has that poisonous for organism any electronto from strip (organic) ability the molecules This is thesenotexercises that to sayin can This logic for con potential sparse eye to this an With organisms, Mars any that unlikely It highly is , 2000) there, 2000) aresevere ------

sible consequences for Earth life (Lederberg, 1999): (Lederberg, life sible consequences for Earth problem of its pos a sample fromand returned Mars the with to deal ability of mankind’s limitations the noted of organisms, exchange interplanetary of an a pioneer consideration the in consequences of the himself Lederberg, Joshua consequences. tionary for biospheric may that have exchange had evolu other, frompotential the one the by and planet life have could in either colonisation This of resulted to time. from time of liveexchange microorganisms have involved could system, infrequent also the toring (Wu, 2005) and during an Earth-entry by a Earth-entry an (Wu,2005) during and toring are moni process the they that less reliable than often are themselves, sensors, critical particularly process. systems, reliable Monitoring containment a more in result necessarily tiple systems monitoring one, irrelevant norimpositionor the an of does mul goal unachievable an bysample specifying return” so on).and It not for does case a“safe advance the feasibility, engineering sample, of the tamination non-con Earth, of (e.g. the desired result the safety to becontained achieve must about sample that the on what to focus it sample, it is Mars important is of of issue containment a the with dealing When size particle through contamination 2.4 process). sterilisation of covalent a rigorous itin bonds (by sundering the be able would to kill humans exists, entity logical abioto such be impossible. if It believed that is be guaranteed cannot low.quite it Nevertheless, still etc.) is , (e.g. entity a -type, cal biologi adangerous posed risk bythe returning it may seem that mind, in thoughts those With Mars is not adapted to live in a host from Earth, Earth, from toa host live in not adapted is Mars from parasite although hypothetical the Thus, pathogens. invading by carbohydrates or produced to peptides respond typically systems immune other mammalian or the human and carbohydrates, and proteins besides little make microorganisms the hand, other On disease? cause and into ahost to come isms organ new any for needed are subtle many so when Earth on hosts for be pathogenic Mars from microbes could how hand, the one On to others. beatall be azoonosis it If might so, conjectural. more is us attack could and exists Mars from amicroorganism “Whether (Lederberg, 1999).(Lederberg, impasse” aconceptual parasites: with totally alien to cope not are equipped systems immune our Considering backward backward Considering ------

Sample Return Mission. Return Sample Mars future for a specification the determining when consideration into taken be should ology microbi in developments New no valid. longer 0,2 the years, past overduced the pro been has that knowledge the considering appropriate time. forstate at of that the knowledge 0,2 nal origi the report, publication of the this until and 1999). time, (NRC, the it” weknow at Thus, life as for limit size lower areasonable constitutes nm 250±50 that the agreed panel machinery], -making [of required estimate the this in inherent tainties concludedwas (as the uncer aconsensus) “given that workshop Board year, same the published it Studies In a Space as “sterile.” to bespecified or liquid air in orderliquidthat for or a fromtoair be filtered organism of an size then-acceptedthe minimum practice microbiologicallaboratory as standard in used was 1999) that size (Rummel, aparticle used mission. the designing when considered be to constraint appropriate an is size agiven than larger of particles containment that confirms and 1999 since approach adopted sample of to the Earth. return the during points at critical –especially mission the sensors during of monitoring lem posed possible by the failure complexity,monitoring exacerbated and prob the and problemsmuch of larger terms engineering in posed or hermetic seal, of agas-tight establishment beverified and could remotely be long-lasting. that solutions amenable was to engineering and hazard, beabiological might that aphysical entity acterise appropriate an was be lodged, could way to char or rock on (or particle dust organism in) an which or the size, projectand organism work that argued discussions However, subsequent requirements. final the prior to defining discussion subject to further draft requirement, couched as a was This tation. implemen project for the requirement defining of a way as size of a certain ofcontainment a particle 1999)Protection (Rummel, the Officer on tofocus Planetary decided NASA by the it originally was microbe, a Mars of a sample carrying from Mars possibility the with to deal NASA, and CNES with itself. system containment of the malfunctioning from the any, out if to failures sort such time little, be very therewill from spacecraft Mars, returning was the right entity to contain, the original letter letter original the to contain, entity right the was The ESF-ESSC Study Group highlights that highlights Group Study ESF-ESSC The that (draft) a particle the With determination the with Groupconcurs Study ESF-ESSC The the as such options, containment Alternative mission joint MSR context of apotential the In µm draft requirement considered was draft µm to be µm value is is value µm ------Figure Earth. Earth. of orbit the to it return and sample the collect will that orbiter the or Vehicle, Ascent Mars the sample, the payload container that is loaded on done of as part the rover/lander that collects the be to have will environment Mars the in sample Credit: CNES/JPL Credit: 6. Whatever is done to contain a Mars aMars contain to done is Whatever 13 Mars Sample Return backward contamination – Strategic advice and requirements 14 Mars Sample Return backward contamination – Strategic advice and requirements (ii) (i) some features. of exhibit these also However,ronmental changes. can matter non-living to adapt and to envi stimuli respond to external to to grow reproduce, and capability ability the the components matter, decomposingorganic and lular into cel energy and by chemicals converting energy of transformation the state, aconstant to maintain environment cellular internal the to regulate ability the of life, basic units as form of the cells sation in include organi These organisms. living describing for belisted can several characteristics Instead (Tsokolov, ofnition life al. Tirard et 2009; agreed-upon lack agenerally defi world, we still natural the in exist not do that already constructed and components designed are systems logical and biology, fieldsynthetic of where emerging the bio level new approaches and molecular and in lular of processes biological cel at the understanding Despite impressive developmentsEarth. our in on life far, i.e. oneSo there only example is of life, 3.1 l l l size limits and Life we as know it 3.

There are three prerequisites for life as we knowthree areThereprerequisitesas we life it: for Life we as know it bon to form four covalent bonds to other atoms atoms other to bonds covalent four form to bon of car capability it the is particular elements. In trace several other and sulphur phosphorus, , oxygen, hydrogen, carbon, from made composedare compounds of chemical Carbon for complex molecules. biochemical a stabiliser aheat as reactions, conductor metabolic as and in as a partner processes, reaction for diffusion Water aselective solvent as serves necessary as habitable. environments to be defined restrial the temperature forextrater range limits This state. aliquid in be availableat temporarily least Water: Life on Earth requires to water has which on Earth Life and other key elements: All organisms organisms otherkey elements: and All , 2010). ------(iii) et al. et reduced Schulz sediments; Thiomargaritanamibiensis 750 characteristics’). their observed and cells est (see size genomebetween cell and below: size ‘small correlation there no is clear although size categorised by also are cells Small rod-shaped cells. volume of and diameter or length, coccoid cells, or volume of diameter the expressed as generally is life, of units the basic dimension of The cells, limit for life size of minimum 3.2 et al. et Angert gut; lated from surgenfish genome size. Bacteria range in size from to size 700 in genome range Bacteria size. asand viruses, rod-shaped and filamentous and for head-tail capsid or length size asmeasured are also dimensions virus to cells, Similar cells. living replicate inside only can that Virus particles are small infectious agents infectious small are particles Virus

Approaching the issue issue the Approaching organisms on Earth depend directly or indi depend directly on Earth organisms source for processes.energy metabolic Most evolution, an needs Darwinian undergoing capable system of chemical a self-sustained Energy: bonds. carbon carbon– stable with molecules organic complex enables formationthat the of a huge of number and electron acceptors, e.g. O electron acceptors,and e.g. electron H donors, e.g. different by using energy chemical gain can organisms However, organisms. thesising some groups of produced compounds organic by photosyn or by using by performing either of the energy radiation on the rectly Epulopiscium fishelsoni Epulopiscium for largest, the µm Life, which can also be described as be as described also can which Life, (isolated from marine , 1999), to approxi 2 , Fe(III) or S 2 , Fe(II) or S , 1993) and (iso 0 . 0 - - - - - , able length but 0,2 greaterable length than 0,1 have ofcould less than awidth of approximately 0.15–0,2 diameter cell host have would aminimum living a environment an than other in to be free living of number genes minimum the with a coccoid cell It be156 diameter. appears would that in nm cell volume, the DNA cell of the occupies the if 50% source require of 750 would the carbon genes and on CO growing Acell be136 nm. would size cell water, 50% it the that contains then it assumed if is be 110 would anddiameter water needs The cell nm. the genes DNA, (250 50% was DNA) kb cell the and 250 contained cell ‘minimum’ the If key nutrients. supply that association more in of a mutualistic cells state but other growing with of because associations free-liv the of in number genes for growth minimal samples different seen in (see below).cells there smaller are that report publishedit clear was is autotroph.proteins) an as the Since to be free living (e.g. material of number genes, minimal the contain would that of acell size we minimal it know –the (8 DNA). kb genes(diameter eight only nm) of 20 contain could of about per protein) 4nm diameter ribosomes and occupied by proteins (average or a kDa of 30 MW 75% is of cell, which diameter nm A50 size. cell number of genes, controls fornecessity a minimal the and characteristics due to its folding DNA, that structure and size of from calculations It determined was bacteria. be could 84001 observed Mars on the ALH particles McKay 1999) (NRC, Report response in report to by the workshop Council Research aNational in addressed question was This microorganism? a free-living possible of size smallest theoretically the is What Theoretical considerations diameter. in 1 greater than generally are cysts bacterial and spores 0.8–1,2 are formation. Bacterial spore is or response soils cyst in common starvation 0,4 of less than diameters to to miniaturise known environments also are from marine cells bacterial Starved Wang 2007). a 0,1 through pass can that bacteria of reports are “free-living” 0.2–0,4 between are organisms micro 1975). “free-living” Most ultrasmall of the pathogenic mately 0.1–0,2 0.25±0,05 Cells in the environment the may in have the Cells less than workshop NRC The report concluded that (1996) suggesting that 50 nm (0,05 (1996) nm 50 that al. et suggesting µm was the lower size limit for life as as for life lower the was limit size µm Mycoplasma µm filter andBrenchley, filter (Miteva 2005; µm µm for the small forms of human forms of human forsmall the µm species al. et (Robertson µm (Velimirov,µm 2001). A µm. Arod-shaped µm. cell µm, although there although µm,

µm. It possible is µm. µm with avari with µm µm in length length in µm µm) µm µm 2 as as - - - , of past . Mars. on life past of evidence as interpreted been have ALH84001 meteorite Mars of Figure that smaller cells exist that have that reduced greatly exist cells smaller that et al et 0,4 DNA is and noncoding no compact extremely genome an virtually has and Ignicoccus archaeon mophilic see Figure tans equi archaeon the is Nanoarchaeum smallest the oneor hosts and of animal have eukaryotic However, host. by the parasites furnished not all have hostevolved and their lost genes are with that have co- cells these parasites, Gross, 2009).and As havethat reduced greatly genome (Feldhaar sizes parasites bacterial and endosymbionts bacterial are cells The smallest communities. trophic cell syn and parasites, exo-symbionts, and endo- cell, dormant free-living cell, growing free-living cells: sized differentminimally Thereare categories of cells smallest of the 3.3 genes or gene products. source of the required as organisms other with exist but requirement have to obligatory co- an Characteristics (490 kbp, about 550 genes; Huber al et ., 2002; Küper al et 2002; ., 7. Scanning Electron Microscope images like this one one this like images Microscope Electron Scanning 9), a parasite hyperther of is the that Credit: NASA Space Johnson NASA Credit: ., 2010).., mentioned, an As µm in diameter (Huber diameter in µm N. equitans N. species. ., 2002, 2002, ., - - -

15 Mars Sample Return backward contamination – Strategic advice and requirements 16 Mars Sample Return backward contamination – Strategic advice and requirements genome copies per cell, making it an ideal candi ideal it an genome making copies per cell, to have organism to 900 from of 200 this ability al from freshwater environments but not are phyloge have bacteria been isolated also Ultrasmall growth. capable of slow only is and alphaproteobacteria of other capability metabolic the retains but still intergenicshort spacer a very sons region and (ITS) 2002). ‘P. or transpo ubique’ inteins no has introns, of 0.12–0.2 (Giovannoni diameter μm cell age al et from 0.37 to 0,84 length in ≤1600 genes). ‘P. ubique’ varying arod is shaped cell yet discovered (there with examples of many are cells genome bacteria of free-living any smallest the has at 1,350 and genes, requires reducedter and sulfur, contentubique’, organic of seawa dilute the grows in (Giovannoni Sea water Sargasso from in the methods molecular referred 11, SAR to as on by based its detection environment, originally marine the in organisms to isolatemicro used onewas most of abundant the plates (e.g. Schut formed microbes that microcolonies on agar small of adiversity yielded material of organic dissolved but can elongatebut to 30 can more than in situ in using marine from oligotrophic attempts to isolate bacteria Initial beultrasmall. also could cells growing actively that possibility to the were they because starved, environments were small marine oligotrophic in cells mostidea small that the expanded report This diameter. in 0,5 µm less than 0.1have volumes µm less than cell by Torrella Morita and (1981), ‘ultramicrobacteria’ seawater in First described . mine acidic and ice cores slimes, oil waters, soils, lated from marine have microorganisms been iso free-living Ultrasmall The smallest cells free-living from 2to 10 µm. size cell in genome vary but size have can asimilar 1.6 kbp are0.5 and to 1 For have mitochondria comparison, approximately genomics (Woyke cell fordate single al et muelleri Sulcia al et (Nakabachi length cell show in variations wide 0,5 dii and2009). rud Gross, TheC. Feldhaar 2000; (Thao, overlappinggenes many and of reduced genes length genome bacterial (160 smallest the kbp) many with endosymbiont For insect the dimensions. example, cell smallest have genomes not do that necessarily the small with there arecells that is to keepmind fact in important ., 2005). This elongated size is likely due to the due to likely elongatedis size 2005). This ., Candidatus symbiont,Candidatus insect Another 2006). ., cells are elongated tubes that appear to exceed that elongated are tubes cells µm in length, although electron micrographs although length, in µm et al et has has ruddii Carsonella Candidatus ,

., 2005). The isolate, ‘Pelagibacter ‘Pelagibacter 2005).isolate, The ., has agenomehas kbp, of 245 size et al et ., 1993).., approach A similar

µm, whereas chloroplasts µm, µm and with an aver an with and µm 3 and are generally generally are and

µm (Moranµm et ., 2010). 2010). ., levels levels ., ., ------Credit: Center for Microbial Oceanography: Research and Education and Research Oceanography: Microbial for Center Credit: 8. The bacteria “ 8. Figure material. levels of organic high with media in when cultured 0,5 than volumes 0.1 werecell less µm than 0,2 a through passing after filtrates were isolated from All Asia. Europea pond and in Actinobacter class of the Hahn For bacteria. example, related to marine netically proteobacteria and both high- and low-GC and Gram proteobacteria high- both and 0,5 than were less somethe cells of cultivation, after meltedof a0,1 the ice core through of were bacteria even units prefiltration isolated after (Miteva 2005). Brenchley Some and colony forming 0.2–0,4 through samplefiltered was the 120,000-year-old ice glacier core Greenland after were of isolated units melted onyper ml forming col 250 more bacterial than Similarly, medium. substrate concentration organic growth ofthe the in increases stable was even size with ultrasmall the µm 0.03-0.04 of volume cell 0.35–0,5 isolates of was these diameter al et of ( bacteria lineage were that soil members ofVerrucomicrobiales the bacteria were isolated from rice paddy anoxic mall al et (Suzina compounds on organic free living to being heterotrophic and addition in bacteria to be parasitic also bacteriacan ultrasmall living free- demonstrated these that It also diameter. was approximately 0.2–0,3 cells ultrasmall and 0.4–0,8 cells, cycle, growth their during sizes cell aerobictrophic and two display and al et related toKaistia alphaproteobacteria bacteria from soils. Isolates described include an an Isolates described include bacteria from soils.

There are a number of reports of ultrasmall There of anumber are of reports ultrasmall µm in diameter. The isolates included different includedisolates The diameter. in µm ., 2007; Panikov, 2005). These cells are Panikov, hetero 2007; ., 2005). These cells ., 2008).., Two anaerobic,- fermentative, ultras (2003) isolated nine ultrasmall bacteria bacteria (2003) al. et ultrasmall isolated nine µm. The small sizes were maintained even weresizes maintained The small µm. Pelagibacter ubique from freshwater and lakes 3 . It is interesting that that . It interesting is ., 1997).., The mean ”. ”. 3

µm in diameter, in µm with lengths less less lengths with µm filter. µm Even µm filter. The µm species (Duda species (Duda µm with a with µm µm filters filters µm µm in in µm - - cells of cells spheres from protrude rod-shapeddiameter that biofilms found in acid mine drainage referreddrainage to mine in acid found biofilms from the archaeon been imaged has ultra-small An Pyrodictium 0.2–0,3 100 1 and between and ofrods Thermofilum are of hyperthermophilic sizes cell smallest The orders four much by as as of magnitude. vary archaea can of genera many of hyperthermophilic volumes and size cell the rule, ageneral genomes. As temperatures (>80°C) small and sizes cell have small grow that those at hyperthermophilic particularly environments and growextreme archaea that in al. et (Jarrell Earth early on the them places that history evolutionary an and , novel environments, Earth most extreme the in to grow ability the including characteristics unique rates growth of up to specific 0.47 h with carbon organic ablequently assimilable to grow on natural a 0,1 through passed that bacteria discuss (2007) respectively). al. Wang et positive bacteria (actinobacteria and Firmicutes, al. et (Baker genome per genes encoding proteins of Figure 9. The Archaea, the third domain of life, havelife, of many domain third the Archaea, The genome size (bp) Plot of archaeal and bacterial genomes(from the National Center for Biotechnology Information Database) sizes versus the number µm diameter flat disks disks flat (0.08–0,1 diameter µm Pyrobaculum Pyrobaculum Thermodiscus Thermodiscus and at 0.15–0,17 and and

µm in length, the 0,3 the length, in µm µm filter and weresubse filter µm Thermoproteus, species (NRC, 1999).species (NRC,

µm in diameter diameter in µm , 2011). Many number of protein encoding genes , 2010). Ca: Candidatus; M: Micrarchaeum; P:Parvarchaeum. Micrarchaeum; M: , 2010). Candidatus; Ca: µm wide) µm in and the the and

µm µm -1 . - viral genome incorporated is hostviral into the genome enter into a relatively state stable where lysogenic the or host of eithercell the cause can phages and bacterio called are bacteria infect that Viruses or may by not alipid membrane. besurrounded into aprotein or DNAcoat may inserted that RNA consist of that either agents infective are Viruses 3.4 2010). (Baker al. et history evolutionary in branch early ARMAN that Crenarchaeabacteria and indicating both sequences in found similar ber of genes with havenum high Euryarchaea a ultra-small These Figure genes (Baker 1000 protein coding approximately and kb genome to 999 from 800 sizes showed organisms of ARMAN lineages ofsis three analy proteomic and metagenomic A ribosomes. µm 0.009–0.04 of volumes cell with were approximatelyThe cells 0,3 al. et Comolli nanoorganisms; acidophilic Mine (archaeal Richmond organisms ARMAN as Viruses

9 for genome versus size of number genes). µm in diameter diameter in µm et al et 3 and only ~92 ~92 only and ., 2010;., see , 2009). 2009). , - - - , 17 Mars Sample Return backward contamination – Strategic advice and requirements 18 Mars Sample Return backward contamination – Strategic advice and requirements and a particle diameter of 42 nm. The parvoviruses The parvoviruses nm. of 42 diameter aparticle and DNA genome have B, hepatitis at kb smallest 3.2 the as such The hepadnaviruses, of nm. 80 diameter at 3.5 aparticle and kb viruses RNA the among genome have smallest the sarcoma Rous virus, as such Retroviruses, viruses. filamentous small as and morphology, becausesize of such be difficult from viruses. genesinclude transmitted that ‘genomic and islands’ islands’ ‘pathogenicity have itschromosome bacteria many in and inserted coli, Krupovic genomes (Anderson al et viral entire and infection, active during host the metabolically ing reproduction genomeby keep viral aid that viral the genes host in metabolic archaea, and bacteria in systems immunity viral include 2009). These 2005, Sullivan genes 2008; (Paul, transmitted ally specieshost of show bacterial later ubiquity the 2009). Moreover, and genome sequences of viruses Rohwer Thurber, (Suttle 2005; and of magnitude bacteria (prokaryotes)exceed of order those all by an numbers for their example, ocean, the ments. In most environ in are diverse viruses and abundant al et (Prangishvili of life domains three all from sequences shows that arelationship to viruses hyperthermophilic acidophilic, the infects that ADNA virus 2006a,b). al et not previously been observed (Prangishvili that had morphologies had have identified that been species –those hyperthermophilic infect that those particularly and viruses about archaeal known is For little very bacteria. example, important cally medi target that viruses and viruses, pathogenic animal other and emphasis been onthe has human since of most organisms, of viruses understanding present. However,also our gaps there many are in was life cellular that indicate mostwould likely morphologies) (unusual particles sample on aMars virus-like or phages).viruses the detection of Thus, (most have bacterio likely likely viruses also would they forms on Mars, life there wereif Earth-like it that follows of life, domains from all organisms 2009). (Forterre, Forterre Prangishvili, 2005; and development early and not is known of life origin possible evolution role the early their and in their and viruses of The origin cells. from ‘free-living’ descended bionts, viruses there no is evidencethat endosym parasitesand microbial Unlike products. biochemical of viral for for replication synthesis and require ahost cell viruses parasites, archaeal and rial bacte host with genome. the replicatesAs and with The detection of viruses in a Mars sample could sample in a Mars could viruses detection The of Since viruses are presumed to be associated with arepresumed to be associated with viruses Since Only relatively how recentlyOnly it has been realised for example, that has 18 genomes has for that example, whole viral et al et Escherichia 2011).., of Escherichia Therestrain is a Sulfolobus Sulfolobus species agene has ., 2006b). ., ., 2011; 2011; ., et al et ., ., ., ., ------have a particle size ofhave 18–26 size genome. a5kb with aparticle nm Credit: Graham Colm Electron micrographof 10. Bacteriophages. Figure particles were first reported in the purple thenon-sul purple in were reported first particles (GTAs). agents transfer These -like gene as known particles transducing of viral-like genetic-transfer thereand have agents, been reports lytic beboth to bacteriophages can that addition In 3.5 entity. that of replication active to enable the metabolically and to be alive has sample and to Martian bepresent same the in host has putative or the Martian types, cell to these and sophisticated specific require a very would which host, as cell be able aterrestrial to use have entities Mars to putativeeither these virus-type biosphereFor consequences potential Earth’s on the reproduce by themselvesbut need ahost organism. al. (Comolli et viruses archaeon observed was to have attached ARMAN acidophilic even ultra-small that the It interesting is genome at 1.2 Mb. viral known largest the eter with diam in nm 400 is protists, infects that mimivirus, of 17 size (Faure aparticle nm has al et 2, type DNA porcine circovirus single-stranded the observed, virus from to 50 >200 The smallest nm. at 4kb. The DNA bacteriophages have arange size genome described far of phagesmallest any thus The However, not are able stated above as to viruses Gene transfer agents (GTAs) agents transfer Gene Escherichia bacteriophage ø-X174 bacteriophage the has , 2009). , ., 2009). ., The - - Table 2. Smallest organisms 2. Table includ host range their and archaea, and bacteria species prevalenceof different of GTAs, in their eukaryotes. evolution early role the tant of in prokaryotes and for possible GTAs impor ancient their origin and an 2010), Archibald, and implying thus host (Richards alpha-proteobacterium)an proto-eukaryotic into the be to (believed mitochondria the of incorporation have tobeen hypothesised be involved also the in GTAs of gene host exchange. purposes forthe the by have and nature been usurped parasitic instead al Matson 2007; et Stanton, 2000; Beatty, and (Lang defective are phages they that been suggested has Beatty, 2007). and replication (Lang host ofany genes the during it possible is that believed for GTAs to incorporate manner, it is this In host of lysis cell. the in resulting without archaea, and bacteria unrelated genetically phylo including hosts, to different this transfer can capsid hostof genome the where viral they into the incorporate segments randomly of GTAs they that is characteristic Auniversal 2007). Beatty, and (Lang to 4.4 13.6 DNA kb with nm to from 80 30 size in Matson al et Leung 2000; Beatty, and Lang 2008; negative gram-positive and bacteria(Biers al et gram- archaeaand other of strains specific as well as genome oforder most the species Rhodobacterales in (Imhoff, and1984) thehave in been since found capsulatus Rhodobacter alphaproteobacterium fur General GTAs Gene Transfer Agents 2 type circovirus porcine DNA single-stranded Smallest virus observed: Viruses Thermofilum of Rods archaea Rods of “Pelagibacter ubique” living free to be genes of number minimum the with A theoretical rod-shaped cell living free to be genes of number minimum the with cell coccoid A theoretical Mycoplasma bacteria:Smallest Microorganisms Organisms ., 2005), thus implying that GTAs that have implying 2005), lost., thus their While many questions remain about the origin about origin questions the many remain While of GTAs it not is origin known, the While GTAs ranging bacteriophages, resemble small et al et species ., 2005). 2005). ., bacteria 0.03–0,08 0,017 1–100 length in µm 0.15–0,17 diameter in µm length in µm 0.37–0,84 0.12–0,2 diameter in µm µm >0,2 Length: <0,1Width: µm 0,2 – 0.15 0,2 0.1– Size µm µm µm µm ., 2010; 2010; ., ., ., - - -

phylogenetic al (Baker et tree of life deeplygenomes, appear rooted to the bevery and in reduced significantly with ultra-small phologically are mor that methods microscopic molecular and observed acidfrom extreme environments using archaea have Other been dimensions. cell ultrasmall environments have reduced greatly genome and sizes extreme in archaea living many Also, environments. freshwater, ice marine, and in soil organisms living 0,22 through pass of environments can archaea from avariety Thereis and considerablethat bacteria evidence to new requirements 3.6 bacteria. marine in Clearly, GTAs amajor are source of genetic diversity environments al et (McDaniel marine in rates transduction previously reported for viral than higher times ratesduction amillion more are than it GTA now is that - estimated Surprisingly, trans consist viromes of GTAs. of marine portion a large there evidence that is infection, cross-domain ing ficult to differentiate differentiate fromGood non-lifeto forms. ficult dif cases, many in enumerate,to observe and and, difficult are form that biofilms, those particularly and Microbes substrates, tosolid attached biofilms. to form ability the and strata solid to the attachment involves that to have ice, likely are alifestyle in ets pock brine cores, and deep sediment rocks, desert and deep basaltic live on including that rocks, Earth on microorganisms For example, settings. similar in life Earth as characteristics same some of the develop could and life Earth as sources energy same the use likely will on Mars form a life that given sample, aMars in exist could that microbes of groups physiological potential the straining for con information critical be will sample the tainer. not would escape from asample con aparticle such that absence of or to putative guarantee organisms be employed asample presence for to the assess or could methods various then exist, does organisms . survive or state, starved in a biofilm, asyntrophic as cells other with association live in they if particularly exist, could limit size minimal theoretical approaching the phylogeny their physiology. and Cells cells, est about the small make to generalisations difficult is it that fact point to the clearly they been cultured, environments, ofdiversehave range different not from a most microorganisms like archaea, these If an acceptable minimal size limit for living for living limit size acceptable an minimal If From new knowledge The geochemical and physical context of context and physical geochemical The µm filters. Many of these arefree-these Many of filters. µm ., 2010).., While ., 2010).., ------19 Mars Sample Return backward contamination – Strategic advice and requirements 20 Mars Sample Return backward contamination – Strategic advice and requirements • that: recommends Group Study ESF-ESSC the aconsequence, As zero. be to demonstrated be cannot but still negligible, almost lower and far be to considered be can ties enti agent-type gene transfer and by virus-type posed risk potential the requirements, replication and specificities their considering organisms, cating appears risk to below self-repli for free-living this be low, but not is if demonstrably that zero. It adds biosphere form appears to life Mars by areturned Earth’s the on effects for large-scale potential the conclusion (1997, reports NRC from the 2009) that entities. agent-type gene transfer and virus-type but also biosphere Earth’s the for consequences having potentially as considered are entities biological free-living self-replicating only not that mends Group recom 2), Study ESF-ESSC Annex the riskperception the ing workshop it oversaw (see recommendation the expressed dur following and on out.this, Based be ruled cannot organisms Earth to with interact GTA-type and ability entities’ type virus- forms on Mars, life there wereif Earth-like Group Study over the considers years, past the that, produced newHowever, knowledge mind in bearing entities. biological replicating with associated those primarily are to Earth materials of Mars return intentionalfromthe arising effects large-scale that to besafe. proven until quarantined remain should and danger carbon-based is pose a that of could size any particle a that possibility there areal is then for analysis, container. However, lab the once samples in are the lower for chance microbes to escape sample from the there be aconsiderably would were then case, the cores this If rocks. and on entities drill virus-type and/or of microorganisms attached possibility the in concern lies biggest the viable microorganisms, water (melted liquid include ice) samples with or air al. et Raoult 2008; Young, and (Martel not deposits, organisms mineral have to be recently determined been reassessed and They blood. in human later and identified minerals, formation hypothesisedto causethe and of these minerals specific with association in observed first ofreports “nanobacteria”, 100 particles sized nm were numerousthe examples difficulties of these conclusions (1997, reports NRC from the 2009) diameter should be considered as acceptable. as considered be should diameter 0,01 than smaller anyparticle of The release Since it is unlikely that samples from Mars will samples will from that Mars itSince unlikely is The Study Group also concurs with another with concurs Groupalso The Study the Groupwith Study ESF-ESSC concurs The , 2008). , µm µm - - - - handling of a sample. asample. of handling the affecting properties other and hardness shape, of terms in Mars from returned be could that material of variety the simulate to Figure • tional experts to determine: experts tional groups of interna reviewed by interdisciplinary released have would to beindependently tially poten size particle maximum actual the organism, or GTA-type avirus-type contain theoretically (asassurance presented Chapter in 4.5). adjustment to required achieve level the overall of considered apotentially as of be up to can 0.05 particle μm unsterilised single 0,01 than larger requirement the case of not aparticle In releasing cost. at reasonable achievable best the is range a such that demonstrated be it can tolerable if 0,05 than but smaller 0,01 than larger particles of The release operation. and systems sion mis the designing when requirement basic line thebottom as considered be should level This large). as twice 0,017is almost i.e. µm, (theGTA smallest observedlarger) or virus-type est GTA observed 0,03 is larger),order of GTA-type magnitude (the small of 0.12–0,2 range the in observed are self-replicating microorganisms ing self-replicating free-liv (thefree-living smallest whether organisms, any to contain be unlikely 0,01 than smaller particles Unsterilised In such a case, and because the particle could could particle the because and acase, such In 11. A Mars sample simulant (MSS) is a 10 g sample, intended intended a10 is gsample, (MSS) simulant sample AMars Credit: Dr. B. Hofmann, University of Berne of University Hofmann, Dr. B. Credit: µm cannot be met, the release of the a bemet, cannot µm µm can be considered as as considered be can µm µm, i.e. more than one more i.e. than µm, tolerable systems-level systems-level tolerable

µm, i.e. three times times three i.e. µm, µm would would µm µm µm - - - - - • IF YES: IF under any circumstance. 0,05 than larger of aparticle groupevent, study considers the release the that arelease concern following main to be the likely are organisms self-replicating free-living As ism. organ an such may bear particles but larger that microorganism, a free-living to contain unlikely 0,05 than smaller aparticle that group Study ESF-ESSC considers The observed. (non-free-living)of smallest the microorganisms 0.37–0,84 of 0.12–0,2 a diameter with ubique” observed (“Pelagibacter microorganism self-replicating of free-living any diameter smallest of 0,05 A dimension µ 0,05 than larger particle unsterilised of asingle release Any ii) i) achievable at reasonable costs, whether this size value is the best reasonably best the is value size this whether 0. 0. 0. 0. 0. 0. 1. 1. can be considered be can tolerable. release the whether of a particle such discipline, relevant other any and virology microbiology, developments in the fields of astrobiology, developments fields the in into consideration latest scientific the taking 04 05 01 02 03µ 10 11 12 particle size Released unsterilised µm µm µm µm µm µm µm m µm). This size is also half of the diameter diameter the of half also is size µm). This at r the lowestachievable Potentially tolerable Reviews r m is notm is acceptable. easonable costs Unacceptable µm is less than half of the half less than is µm Acceptable equir µm is not is acceptableµm

µm but a length of but a length µm ed µm would be would µm observed (notfr Smallest micr of afr Smallest observeddiameter Smallest GT - Smallest virusobserved ee livingmicr requirement as presented above is reviewed and and above reviewed presented is as requirement consequence, a As for entities. size biological on minimum ing understand maycurrent shatterour mechanisms and entities discoveries of new agents, future that over 15 past the years. beat aslower pace than possible, indeed is it will this and future, the decreases in microorganisms living GTAs or free- for size viruses, minimum expected (especially genomics), the if that oneassume can threshold. size minimum represents afundamental functionality protein that products and particular to for code have size molecules to beof acertain biosphere. Earth’s the impacting potentially as entities type GTA- and consideration given virus-type to Mars the is this behind driver microbiology,in main the 0,2 requirement decrease size of the (froma drastic The recommendation aboveput forward represents 3.7 reconsidered on a regular basis. regular a on reconsidered However, possibility the no disregard one can techniques and knowledge current on our Based machinery, microorganisms’ free-living Within µm to 0,01µm Perspectives for the future for Perspectives the A observed oor ee living) ganism oor ganism µm). Besides new knowledge gained µm). gained new Besides knowledge it is recommended that the size size the that recommended it is unsterilised particle released. unsterilised particle sizeunacceptable range for of acceptable, tolerable and Representation 12. Figure - 21 Mars Sample Return backward contamination – Strategic advice and requirements 22 Mars Sample Return backward contamination – Strategic advice and requirements • report, context ofadvice the provided the in and by this of assurance’. ‘level be labelled variable will particle unsterilised of not an releasing probability present the the In document, variable. the p for limit thean upper event and sets identifies consequences, potential it with dealing Without • above: defined as ment elementsconsidersrisk of three only the two than shall be less environment into the Earth released is unsterilised “ states that mission MSR of an frame the in guideline current The • 1981):ponents Garrick, and (Kaplan approached dependent com on three being as risk requires more 1981, accuracy. In Garrick and Kaplan riskof definition the context, current the able in (referringquantitative to probability). To bework (referring orqualitative to damage) ahazard or sometimes concepts, being to different used describe the language, everyday study. MSR In of this frame the in used terms the of to haveIt crucial is acommon understanding From to level risk of assurance 4.1 l l l for anon-release of assurance level adequate the Defining 4. • • A (set scenario(s) of) ( larger than agiven size than larger particle unsterilised release ofA scenario: the an what the are consequences?) happen, (i.e. if it does fromthescenario(s) The consequences resulting happen?)it will A (set probability(ies) it of) that is likely (i.e.how A probability: less than one in a million (10 amillion one in less than A probability: It is crucial to consider that for an MSR mission mission to considerMSR for that an It crucial is 10 -6 the required level of assurance fornot of level assurance required the ” . It is important to note that this require to note this . It that important is or greater greater or diameter micron of 0.2 particle the that probability asingle i.e. what wrong? go can i.e.

term ‘risk’ term

is

often loosely often loosely -6 ) ) - - - Mars particles attached to outside surfaces of to the attached outside surfaces particles Mars by butbe caused by a breach containment also in biosphere could Earth’s into the particle unsterilised (see Chapter 5) organism a Mars with Earth the for not contaminating of level assurance the as same notsphere is the bio the into particle unsterilised an releasing decisions to be made on the acceptability of a risk decisions to acceptability be on made the informedand analyses for risk/benefit allows this and understood and known consequences well are some cases, itsenvironment. In interactwith will of constituent, how event, the or its main standing under the on depends risk much of very definition component Garrick’s third The and of Kaplan Known knowns consideringand consequences 4.2 size. agiven than larger ticle par unsterilised of an release the for preventing assurance an appropriate level of at defining aims risk level of acceptable an define does report current the ment, it may environment which the befound. in or apriori about organism the not if knowing cially espe on bepresent Earth, survive might and Mars from organism unknown an that probability further calculating in challenges practical and theoretical an acceptablyas fiedlowthe because of number It to bespeci has mission. the encountered during environments the in uncertainties known and data on based design calculable, practically and retically scenarios) because both is bespecified it can level Theassurance spacecraft. of overall (covering Focused on the review of the current require current of the review on the Focused Approaching the unknown unknown the Approaching . The introduction of an an introduction of . The not intend to intend not , but rather it , but rather ------of a Risk Group 2pathogen. Group aRisk of • equipment. and on practices adequate levels, laboratory recommendations or agent, given are of organism Forgroups 2004). group each of (WHO, pathogens four (WHO) ageneral framework, identifying sets World the Organisation instance, Health this In classification. on their depending handled are agents 2001). Nations, (United theand adverse on ing effects humans - caus as recognised compounds of organic use and production the constrains or strongly abolishes Convention that on Persistent Pollutants Organic United the Nation Stockholm with case been the has This and/or risk. to to reduce betaken actions this Figure • • • preventive measures are not usually available. preventive not are measures usually treatment and Effective or indirectly. directly to another, from one individual transmitted ily be read can that and disease or animal human risk): nity commu and individual Group 4 (high Risk available. are ures treatment andanother. Effective preventive meas to spread from individual one infected ordinarily but not does disease or animal human serious risk): munity low com risk, individual Group 3(high Risk limited. of risk spread the available and is of infection tive treatment preventive and are measures but may effec cause serious infection, exposures Laboratory environment. the or livestock munity, to laboratory workers, hazard serious com the to bea but unlikely is disease or animal human risk): community low risk, Group 2 (moderate individual Risk disease. or animal to human cause risk): munity com and Group 1 (noRisk or low individual Another relevant how example is Another pathogenic 13. The bacteria Legionella pneumophila A pathogen that usually causes serious serious causes usually that Apathogen A microorganism that is unlikely unlikely is that A microorganism A pathogen that usually causes usually that Apathogen A pathogen that can cause can that Apathogen is an example example an is ------and that research on mechanisms linking an event an linking research that on mechanisms and knowledge goeswith understanding that It clear is providing communication services to populations populations to services communication providing acknowledged of efits mobile phonesare well (e.g. 2010 in to 5.4 2012). (ITU, billion ben the While 2001 in subscriptions increased from has 962 million of mobile phonenumber The total health. human on (EMF) fields of impact electromagnetic the ing negative consequences not sometimes is possible. of potentially what drives understanding and edge (or a sound having at adequate) least level of knowl or complexity novelty to the Due of some issues, Known unknowns overcome its negative effects. are DDT consideredusing benefits of the to cases, in some that, drivenexceptionthe fact is by This vector control adisease agent as forits use malaria. Convention, exception (with restriction) on made is Stockholm acknowledged byecosystem is the the and health DDT on human insecticide of the negative the impact to note while interesting that and apply adequateanalyses decisions. benefit is It to its consequences required is to risk/ perform our knowledge of life on Earth (especially extre on Earth of life knowledge our on by combining bespeculated only can organisms Mars onmade potential assumption Any ogy’. biol ‘Mars there no is known and been found, has on Mars life or extant far,So no evidence of extinct Unknown unknowns have that of to be performed. studies kind the of to be andtype conductedhas research what fies clari of phones. mobile use This the associated with cancer, of brain atype increased for risk glioma, tial do not know. theherepoten is unknown The major what know they scientists and regulators case, this in but negative effects, aboutknowledge potentially particular. in children general and in of phones mobile use the population for in the tions limita some recommend agencies health national 2011). (WHO-IARC, several Similarly, texting or of devices hands-free use the as such exposure to reduce measures recommends pragmatic IARC levels, international and national the at on-going research assessment still are and While to humans. produced by mobilephones possibly carcinogenic as have on health to not develop.EMF had time long-term on the information of impact structured cable-based costly and networks), tight and detailed to build having without developing countries in Research on Cancer (IARC) classified the EMF EMF the classified (IARC) on Cancer Research This is the case, for example, when example, for the consider case, is This The EMF case shows an examplean shows lackof a case of EMF The 2011,In for WHO’s Agency International ------23 Mars Sample Return backward contamination – Strategic advice and requirements 24 Mars Sample Return backward contamination – Strategic advice and requirements the field as field representedthe experience. their by in low,as experts of the beliefs of aconsensus the as ments). However it risk possible is the to establish of of experi afrequency of acollection limit the probability of definition frequency sical clas the in or harmless harmful be could sample the that aprobability estimate to notis possible it of a level uncertainty, such with noteto that However,effects. important it is significant other impact or ecological to have asignificant unlikely biosphere is Earth’s into the organism of aMars Group,Study presented as above) release the that ESF-ESSC the among (and community scientific the among there consensus is point, latter On the • • including: mission, MSR by an posed assessment of risk a real of contamination the reachedfor being on major allow would factors that prevents conclusionsorfrom uncertainty, definitive knowledge, lack of This conditions. environmental and understanding and knowledge ) our with analogue in biology mophile 4Laboratory. level aBiosafety in working Researchers 14. Figure • Whether life exists on Mars or on not Mars exists life Whether organism can interact with the Earth’s biosphere. Earth’s the interact with can organism if assess possible how)(and to definitively a Mars sample, it not the is in organisms there living are If isms organ containing mass)given and size actually of asamplethe a sibleprobability to define (with it not is on pos- Mars, organisms there living are If (i.e. as as (i.e. Credit: Inserm, P. Latron Inserm, Credit: - - - to Risk Group 4 appears to be the best measure. best the be to Group 4 appears Risk to sample of aMars assignment apriori principle, same the tograded alower group. risk Following it to be down about pathogen allows knowledge the further leveluntil of confinement highest the with Group laboratories in contained lated 4and to Risk rate isolated: it is assimi is fatality case ahigh with pathogen applied unknown ciple when an also is appearsprin prevention best to bethe This method. the confinement context, sampleof this In dictable. and pre manageable are hardly by definition and areconceivable mechanisms bydriven unknown (and thereforeunknown unexpected) consequences some way,in framed a level such of uncertainty, with be can material Mars release ofthe unsterilised experiments. and experience past upon building complex, increasingly becomes that incrementaldevelopment the biology of synthetic example, from, for significantly differs This steps. preliminary have limited no or only will tigations inves scientific - the overnight and land sample will the MSR: an steep developmentvery with curve have (if aboutbiology Mars knowledge a any) will beforeicant information sample returned, is aMars signif gather and on Mars organisms discover living While, based on assumptions, some aspects ofsome aspects based on assumptions, While, and/or landers Mars roversUnless future - - - - - • the most constraining: Principle basic versions, to four to least from the (2002) Stewart it. reduceding Precautionary the topicthe or region considered apply country or the on depending widely differs Principle Precautionary application and of the understanding The • • • 2005): (UNESCO-COMEST, conditionsmet are applyshould following when the Principle Precautionary the that (COMEST) asserts research” of thescientific results awaiting without risk serious apotentially for action to take the need reflecting uncertainty, of scientific with adegree high circumstances in applied policy management “a risk as thePrinciple Precautionary defines Organisation World the 2000), (WHO, Health Policies Cautionary Health Public – and Fields Electromagnetic ated or demonstrated to be low. document the In evalu bedefinitely cannot risks The a release. from such resulting risks potential the release and level of preventing assurance a the between made to be has emphasised above,As distinction aclear of context MSR in the 4.3 Ethics of Scientific Knowledge andKnowledge of Scientific Ethics Technology • • • • some scientifically plausible reasoning); reasoning); plausible scientifically some reasonable scientifically are is on based that (that (or scenarios there exist models) of possible harm uncertainties; considerable scientific there exist harm unless the proponent the shows unless of activity harm the riskof the available requirements toogy minimise subject be to best technol should harm significant for potential present that uncertain an Activities Principle: Available TechnologyBest Precautionary predicted. or level no adverse at which been observed has effect below the be limited should activities of safety; controls incorporate should amargin Regulatory Principle: Precautionary of Safety Margin harm. of significant risk apotential pose that of activities regulation preclude automatically not should uncertainty Principle: Precautionary Non-preclusion time. any later at or costly difficult more significantly bemade teraction later will there aneed is now, to act effective coun since unacceptable; morally otherwise irreversible for present generations or or future serious or even sufficiently is harm potential the idealisation; and tion relevantother levels of factorsabstrac by higher of ignorance increasing time same at the without term short bereduced the cannot in uncertainties The UNESCO World on the Commission UNESCO The The Precautionary Principle Principle Precautionary The Scientific Scientific . - - - - -

Prohibitory Therefore, Prohibitory the of applied, harm. if sampleof presents aMars no appreciable risk applicable. or justifiable not is approach Principle Precautionary of Safety Margin aconsequence, As the beavailable. vations will no previous and obser beestimated release cannot framework. regulatory a or monitoring implemented is programme the control, without accept that makers will nor public neither the policy groups or and individuals by influential be raised also will posedmission risk by the potential of the issue the that beexpected It can public. from the major draw attention will programme but this negative biosphere on the impact not bediscarded potential the of a sample Not can from only Mars. approach context return applyof the the cannot in The of the International Commission on Radiological on Radiological Commission of International the its 1990 Recommendations reductions. In these with associated costs the and doses the reducing between haveegies been concept based on the of optimisation protection radiological strat decades, Overpast the Achievable (ALARA) Reasonably As Low As of Concept The 4.4 particles. Mars of unsterilised release potential the ering consid when applied is Principle Precautionary Technology Available Best the that ommends Group rec Study ESF-ESSC sample the and posed by aMars risks potential the with perfectly provided Chapter below. in 4.4 are details concept further and of this for use the Justification regulations. emission some pollutant Available Technique concept in optimisation used approach theBest This Principle. to strongly relates Technology Available Best be the evant to apply Principle would Precautionary the mission. MSR of the cancellation to the PrinciplePrecautionary approach simply would lead the associated conditions presentedthe above align • of harm. of shows it that presentsactivity no appreciable risk proponent the beprohibitedshould unless of the harm for significant potential present uncertain an Prohibitory Precautionary Principle: present they that no appreciable of risk harm. It not is possible return to demonstrate the that As mentionedAs consequence earlier, the of a The definition of Precautionary Principle Principle and of Precautionary definition The rel model only the on Stewart’sBased structure, Emission optimisation strategies optimisation Emission Non-preclusion Non-preclusion Precautionary Principle Principle Precautionary Precautionary Precautionary Activities that that Activities - - - - - 25 Mars Sample Return backward contamination – Strategic advice and requirements 26 Mars Sample Return backward contamination – Strategic advice and requirements practical suitability of particular techniques for pro (2008). (IPPC) Control and Directive Prevention Pollution core at Union the European Integrated of the also is of theEnvironment Atlantic North-East of the Marine the Protection for Convention OSPAR the in it specified is particular, environment. In into the release the of pollutants at limiting aimed approach BATThe concept optimisation an is The concept of Best Available Technique (BAT) ronmental consequences beestimated. cannot breadth of envi environment therefore and full the on howon the impacts radiation uncertainties but there many are dimension health human the to aspects detriment environmental the adding applied protection to the environment of the by be could ALARA In principle, effect relationship. dose– on based is awell-known and individuals 2003). (NEA-OECD, sources radiation artificial contributing per from year all for members setat is public 1mSv of the dose limit the that stating upper by an limit constrained is tion optimisa level (it of exposure to beALARA), has approach not does mention aminimum ALARA the 2003). (NEA-OECD, occur will situation exposure an that likelihood the and individuals of number exposed the doses, individual into account taking lowexposures dose after risks proved human effective tool for to managing bean has relationship recommended by ICRP. ALARA dose/risk the refers using and doses assessed to risks on individual focuses term ALARA, the introducing of protection,the description optimisation of This of protectionmisation for practice as: Protection (ICRP, 1991), opti the describe ICRP and their methods of operation which indicate the which indicate of operation methods their and of activities the in development stage advanced Techniqueand (EU, as 2008): effective the most The ALARA approach on protecting is focused ALARA The ent economic and social judgements.” social and economic ent inher the from to result likely theto inequity limit (risk constraints), as so exposures of potential case the in (dose to individuals constraints), the or risk to individuals the on doses restrictions by strained - con be should procedure This into account. taken ably be all kept should to be received arenot these certain where exposures incurring of the likelihood and exposed, of people number the doses, of individual the magnitude practice, a within source to particular any relation “In The IPPC directive defines Best Available Best defines directive IPPC The protection, context while of the radiological In a chievable, economic and social factors being being factors social and economic chievable, a s l ow ow (1992) and and (1992) a s r eason ------

viding in principle the basis for emission limit values values limit emission for the basis principle in viding assimilative capacities (Moberg al assimilative et its determining environmentinto the rather than or reduce input of the hazardous eliminate of will BATthatThe focus is more on methods (c) (b) (a) awhole. as environment the on the impact and emissions to reduce generally that not practicable, where is and, to prevent designed for humans. to beachieved environment for not the and only ALARA sources of allow release would BAT to all applying that objectivessame be assumed it and can 2003). source of release (NEA-OECD, on asingle BAT focuses while individuals, affecting potentially sources considers all ALARA that fact the in lies difference non-human species. Another including environment on the awhole, impact as the limit to also and beyond by borne individuals those only of integration consequences the are BAT that allows release relationships.the at By considering its source, consequences) (including risk known. are covers components where situations of all ALARA assess to (Moberg difficult riment (either or economical) societal is biological, far-ranging application conditions where under det level. However,or improving that BAT a more has reaching level cost associated of with and emission considerboth arbitration to that has be on made environment. protection the They and mise of man economicsconsider and to opti science, technology BAT. and strategies Both ALARA between ties It been noted has there obvious are similari that and BATALARA comparison human health through well-defined dose–effect dose–effect well-defined through health human

It appears clear that BAT is a suitable BAT asuitable is that clear It appears approaches both Nevertheless, tend towards the impact-oriented is on focuses and ALARA a whole. a as of the environment of protection level general to the operator; accessible reasonably are they as long as question, State in the Member inside produced or used are notor the techniques whether advantages, and the costs consideration missioned; decom operated and maintained, built, designed, ‘best’ into taking conditions, viable technically and sector,relevant economically industrial under the in implementation allows which ascale on ‘available techniques’ is the way the and which in installation used ‘techniques’ means most effective in achieving a high a achieving in effective most means shall include both the technology both the technology shall include means those developed those developed means et al et ., 2004), whereas whereas 2004), ., ., 2004). ., - - - - institutional guidelines from around the world. the from around guidelines institutional and legislations regulations, various in befound can toxic or waste radiation. cals, chemi to due exposure toto adverse effects health individual of risk applied an the when considering are not effects considered tolerable. is It primarily abovethresholds adverse which ard when defining spread beyond astand United the being States as 1991). (Kelly, zero’ essentially is that risk lifetime ‘maximum being the by set FDA was as application, ‘one amillion’ in its and value relevance on the ofconsultation this expert apparently and wide without this, Following required is (Kelly, action 1991). regulatory further zero’ therefore and to be ‘essentially belowno which risk isFederal considered register, where minimus de minimus 10 or million’ often comes in a figure ‘one the across considered acceptable or tolerable. decisions These have to be on based levels risk of or procedures. substances of various use the ing fram and prior to analyses authorising risk/benefit have perform to authorities Regulatory tanning. or even sun examination medical during security, airport through when going radiation harmful potentially to the forexposure case also is This etc. water food, and in houses, environment, the in in life; present are substances daily hazardous in Many 4.5.1 by regulators 4.5 meet them. to developed have be to would technologies new technology, available with achievable be not requirements these Should magnitude. and probability release the for requirements adequate recommend and define to alimit set to important it seems (at cost) used, areasonable able are techniques release. of this magnitude the and release unintended of an probability the minimise to order in concepts operational and technologies thebest use of the mobilising allow would This involved. and operations systems the of cificities spe the to adapted and mission Return Sample of aMars frame the in approach considered be to an acceptablean – or tolerable – level of one risk, -6 Several examples of the use of ‘one in a million’ of ‘one use examples ofSeveral the amillion’ in avail that implies BATHowever, only while The values from these examples only fromtheseprovideexamples only risk The values From concept the there, of ‘one amillion’ in what considered is investigating to be When Quantitative risk levels risk used Quantitative . This value originates fromthe concept originates value of. de This The use of ‘one in a million’ amillion’ in of ‘one use The risk contained in a1973 US in contained the risk notice in - - - - - excellence in risk management risk (Kelly, 1991). in excellence to bemet to demonstrate ‘ the standard’ being tion for it it, 10 appears the that 10 of regulation 10 of of risk death individual of an guidance HSE the Therefore, or Australia). (as risk UK the in annual US) the (especially risk in or an either alifetime it covers: timeframe on the be it can ies depending scope of seriousness. full of the DALY the Interestingly, approach integration allows HSE). or UK EPA guidance (e.g.death Australian of risk to the guidelines), of ECHA Superfund ofrisk from the developing (e.g. a cancer US EPA bly. seriousness It on consequences, of the varies the considera and varies value overall its significance (10 used beconsidered acceptable. also as levels of can risk EPA) and some (e.g. cases level, in ECHA higher same towards the pointing all While individual. for negative consequencesability borne one by only the accept defining level, i.e. levels individual at the Figure (earthquakes, hazards natural instance: for include intervention; these notare to human attributable bedetermined. cannot consequences potential of mission, areleaseMSR cer). However, of case the the in stated, already as of risk developing acan the (inhazard most cases, to aspecific exposed sequences individual for an negative con and quantify define to clearly ability Table given values The in 3were based on the consequences 4.5.2 accepted now is and considered as by regulators -6 More importantly, the use of the 10 ofMore the use the importantly, It is important to note that while the figure figure the to noteIt while important is that All over the world, populations face hazards that that over face hazards world, populations the All While it is almost impossible a justifica to find it almost is While per annum is hardly comparable FDA hardly to is the per annum 15. Tsunami Zone Hazard sign. Approaching events with unknown unknown with events Approaching -6 ) is the same in most of the cases above,most of cases in the same the ) is -6

lifetime risk of risk cancer. lifetime Credit: NOAA -6 value has been been has value -6 value var value ------27 Mars Sample Return backward contamination – Strategic advice and requirements 28 Mars Sample Return backward contamination – Strategic advice and requirements assurance level in the pharmaceutical and medical medical and pharmaceutical the level in assurance thesterility be found: can defined be accurately of event kind whose consequences this cannot ing events. of natural of occurrence probability the than tighter much are that levels assurance impose tend to authorities regulatory aconsequence, as events; fornatural lower than much is events man-induced these to acceptance activities). public’s these level of general The ing avoidable potentially (atare by least not perform activity events to attributable human By definition, • example: for occurrence, However, be associated to their can probabilities predictable. not hardly often are becontrolled and be implemented, events can strategies these can mitigation While spread or the impact of diseases. and eruptions), volcanic floods tsunamis, Table 3. • • Organisation (ISO)Organisation International Standards Authority Protection Australia Environment Executive (HSE) Safety and Health UK (WHO) Organisation Health World EU Water Drinking Directive Directive Quality EU Air (ECHA) Agency Chemical European (FDA) Administration Drug and Food US Protection Agency (EPA) US Environmental Organisation demics is 27 years (Stafford, 2005) years (Stafford, 27 is demics pan influenza global between The span average 1992)(Morrison, years 100,000 areas: for years, urban 3,000 area: for populated years, 300 Earth: for total impacts Average Tunguska-class asteroid between interval 2008) years (USGS, 30 next the in earthquake tively, 6.7 or greater of producingamagnitude respec havecoast, 6%, of and 7% probabilities FranciscoGregorio Peninsula San the Fault along Bay, East thethe TheCalaveras San andin Fault Some example of regulatory guidelines approach guidelines Some example of regulatory Use of ‘one in a million’ in various regulatory frameworks regulatory various in amillion’ in ‘one of Use (buildings, bridges…) structures for Reliability IndustrialPlant Hazardous from Risk Individual Offsite and tolerable risk unacceptable between a limit setting for guidance General WaterDrinking Quality compounds to carcinogenic Exposure compounds to carcinogenic Exposure Exposure to chemicals compounds to carcinogenic exposed animals from produced Food sites waste hazardous uncontrolled up to clean ‘Superfund’ programme Scope - - - - - the collapse of astructure of collapse the of aresult as dying of risk individual Annual an industrial accident of aresult as dying of risk individual Annual dying of risk individual Annual source asingle from resulting to death) illness of (degree effects various compiling by people on burden disease overall awayto approach –provides year) life DALY (disability-adjusted individual Annual exposed to compounds carcinogenic individual to an levels risk cancer Lifetime exposed to compounds carcinogenic individual to an levels risk cancer Lifetime exposed to chemicals individual to an levels risk cancer Lifetime compounds to carcinogenic exposed animal from food eating individual to an risk cancer Lifetime site to acleaned-up exposed individual to an risk cancer Lifetime Risk that “ that (2008) Facilities Healthcare in states Sterilisation Control and (CDC) for Disinfection Guideline process. The USCenter gone forDisease sterilisation present is microorganism item under has on an that viable asingle that one out chance of one million expressed a 10 is normally SAL sterilisation. object after on an present being of aviable microorganism ability items. of sterilised use on the required level depending the processes define and levelciency of sterilisation effi the haveindicators to quantify been devised some sterilisation, or to achieve total sterile, totally possible item to demonstrate hardly is an is that it of item. While use that the associatedease with (e.g. order aliquid) in to avoid- of dis transmission asubstance object or of in an surface on the ganisms microor all destroyto aims production. The process drug and surgery methods) medicine, key in is (seeSterilisation Chapter 1.3 forvarious the (SAL) Level Assurance Sterility consequences to materialise. allow would happen that will events that but rather happen consequences will certain that abilities prob not as considered be should examples these case, release MSR the for As of facilities. nuclear the and reliability of aircraft reliability the industry, Sterility assurance level (SAL) assurance refers prob toSterility the a SAL of 10 a SAL - n -6 ; a SAL of 10; a SAL generally is accepted as appropriate appropriate as accepted is generally -6

means that there that is means 10 10 10 10 10 10 10 10 10 acceptability of Limit −6 −6 −6 −6 −6 −6 −6 -5 -4 to 10 to to 10 to -6 -6 - - - - - • • • 2006): (EASA, condition failure fies fivesystem levels of of severity identi (EASA) AviationAgency European Safety the aircraft, transport for large regulation thiness airwor In its airworthy. to be aircraft transport order met are in to considertargets acommercial Unitedthe some safety States require that specific and Europe in processes certification Airworthiness Civil Aviation population. or the have individual on an would unit unsterilised an that impact the knowing process without sterilisation the it that frames being levels presented Table difference in main the with 3, tolerable risks individual to the similar is million’ recommended level ASAL of ‘oneorganisms. a in harmless and pathogenic between discriminating products without medical and pharmaceutical cal of unit 10 the of on probability a non-sterile based generally is drugs sterilised (SAL)Level terminally for Assurance Sterility acceptable minimum The ten. base to the power anegative as expressed commonly tion, func aprobability is sterile is item that given any “ recommendation (PIC/S, following the 2007): Co-operationscheme (PIC/S)Inspection expressed (2004). cells and sues tis for organs, assurance quality and to safety guide Pharmacopeia (2011) of Europe’s Council the and European by Europe applied the in also is ard that astand is drugs injectable items and surgical and amillion”. thanin one that less unit is sterile non- probability a a of obtaining achieve to sufficient lethality verified abiologically in result must process (USP, for sterilisation tion’s 2011): guideline “ conven US Pharmacopeial the follows level actually (e.g. outcomes infections) patient adverse any with not associated and arbitrary strictly was SAL barriers) of the body natural the that integrity lost has tissue (i.e. tissue compromised to contact intended items for Inspection Convention Inspection Pharmaceutical the and • • Although “sterility” is an absolute term, the assurance the assurance absolute term, an is Although “sterility” tional capabilities or safety margins or safety capabilities tional func reduction in condition: slight failure Minor or safety No on effect capabilities operational loss hull with condition: normally failure Catastrophic margins or safety capabilities functional reduction condition: large in failure Hazardous margins or safety capabilities functional in reduction condition: significant Major failure The SAL conceptis theSAL applied The formost criti Pharmaceutical level, the international At the level of 10A SAL ” . It further states that “ states that It further -6 for most critical medical medical critical most for the choice ofthe a10 choice ” . This This The The -6 ”. -6 ------

EASA states: EASA Forcondition. of condition failure, catastrophic the multiple fatalities. in to result expected are conditions failure catastrophic while crew cabin or of passengers number to asmall fatal or injury serious to imply conditionsexpected are failure Hazardous to several hundreds. from a couple ground)sengers on the and ranging - for pas (both fatalities in but result defined would eventof acatastrophic be preciselysuch cannot The consequences data. basedon is historical ability non-system operational prob causes) this that and from hour eventcatastrophic (including per flight order ofare set in 10 probability to overall meet an aircraft for large targets safety regulatory the that 2008). 1988),(FAA, approach same the with (Azevedo, In the United States, the FAA uses the same values values same the United FAAuses the the States, In to say whether the target has been met until all until met been has the target to whether say possible is is not this that it with difficulty The aeroplane. designed newly a for flighthour per or 1 x flighthours million 10 ten than per one greater not be such all Conditions Failure from accident that the of probability aserious expect to reasonable It is designs. aeroplane new in this than probability ahigher not be allowed should systems by caused accidents that serious sonable rea It seems systems. the aeroplane’s by caused to Failure Conditions totalattributed were about of cent the10 per ofFurthermore, flight. hours million per one approximately was causes airframe-related and to operational due dent acci thatindicated the of probability a serious evidence Historical have to be established. would values that probability rational recognised was it of adesign the acceptability assessing “In have targets been set forProbability failure each Going upstream this approach, it this appears upstream clear Going Improbable”. “Extremely the term for value probability mate be 1x10would Failure Conditions Flight Catastrophic for Hour per for Probability the Averagelimit upper The than 1 x 10 of not greater allocation an in resulting Failure these Conditions, among Hour of 1 x 10 Flight allowableAverage per target Probability The be Catastrophic. could which aeroplane, an in Failure Conditions potential hundred that one about are arbitrarily, there assumed, it was reason For this numerically. analysed collectively are the on aeroplane the systems -7 -9 was thus apportioned equally apportioned thus was , which establishes an approxi an establishes , which -9 to each. to -7 -7 - - - - - 6

29 Mars Sample Return backward contamination – Strategic advice and requirements 30 Mars Sample Return backward contamination – Strategic advice and requirements • the following: ways including “ states It to be implemented.” arrangements emergency the require offsite would and society for implications have severe which would material, of radioactive material of radioactive release off-site large defines further document This • 2001): (IAEA, targets safety adopted following the (IAEA) Agency Atomic Energy International the released environment.is into the reactor breached is containment radioactivity and the core damage, following when, events occur core release in Large meltdown. possibly resulting spoiled, becoming nuclearfuel the event leading refers release events. Core large toand an damage of nuclear powerregulators coreare damage two worst The events considered by operatorsand Safety Nuclear Maximumtolerable 16. probabilities for some man-induced events andFigure probabilities of some events non-man-induced • • International Nuclear Safety Group (INSAG), Nuclear Safety International • • • • such off-site release can be specified in a number of number in a specified be can release off-site such As absolute quantities (in Bq) of the most of signifi absolute (in the As Bq) quantities 10 cant nuclides released, nuclides cant As a fraction of the inventory of the core, of afraction the As As a release giving “unacceptable consequences.” arelease giving As site, the off the personexposed dosemost to aspecified As 10 10 10 10 10 10 10 10 10 10 1 For Core Damage Frequency: Frequency: For Core Damage For large radioactive release: radioactive For large Following the recommendation the from itsFollowing -4 -6 -5 -5 -7 -6 -5 -4 -3 -2 -1 per reactor-year plants, for existing per reactor-year plants. for future

per reactor-year plants. for future High Low per reactor-year plants, for existing flight hour) aircraft (per passenger on event Catastrophic Maximum tolerable probability : as being “ being : as of a man-induced event aman-induced of tissues compromised with contact in enters item A non-sterile A large release release A large year – UK HSE) –UK year fatalities (per more or 100 resulting in nuclear facility a in Accident - year – AIEA) (per reactor anuclear from active material release of radio- Large off-site numerical criteria similar to large radioactiverelease to large criteria similar numerical off-site on alarge whatconsensus constitutes release, there no is mentions although that IAEA Finally, Figure 2005). ments (SNIFFER, of terms require in same the regarded essentially as be can ALARA and protection ALARP legislation, of Forradiation to bedemonstrated. purposes the principle has Practicable Reasonably (ALARP) As ‘tolerable the is values low region’ As the for which two sidered these between acceptable. broadly as In becon can risk below which limit the as BSO and able (any risk considered is risk larger unacceptable) for tolerlimit higher the as BSL defines HSE UK • • are: radiation, to ionising that exposure in result accidents on-site from eventual, or immediate either fatalities, more 2006): that (UK-HSE, specifies HSE UK accident anuclearfacility, an in considering When Standards. Safety IAEA the marked against haveSAPs Those been bench of facilities. nuclear have in a of targets countries. number been specified Safety Assessment Principles (SAPs) areaSafety the in HSE) Executive (UK derives of anumber Safety Basic Safety Objective (BSO): Safety Basic 1x10 (BSL): Level Safety 1x10Basic The values discussed above gathered are in discussed values The 9: Target and Health UK the United the Kingdom, In

16. 30 years in earthquake greater or 6.7 a magnitude producing Fault Gregorio San The targets for the total risk of orrisk for the total 100 targets The Probability of non-man- induced events average) (annual pandemics influenza Global -5 per year per year -7 average) impact (annual class asteroid Tunguska- Populated area per year Urban area Earth

- - - - Figure but risk, acceptable an to not is equivalent ance kept. be should appropriate and is particle Mars lised unsteri hazardous of a potentially release the for amillion) one in (lower level than assurance current the that Group considers Study ESSC it workshop oversaw, perception ESF- risk the the during expressed recommendations the and level international at adopted the positions the with line in and worldwide applied regulations asampledecision back tofrom bring Mars. the with associated risk–benefit the calculation to cost help issues and understand design mission to out drive enough be stringent would that and widespread governmental and public acceptance, at had alevel has that to begin both was assurance that level of biosphere.intention The of specifying be released would Earth’s into the aparticle that forfied a of containment levelassurance of <10 1999) (Rummel, mission for MSR letter the speci categorisation original the size, of acertain particle a to contain determination draft the with Along of assurance 4.6 It has to be highlighted that the level of level assur the that highlighted be to It has and guidelines current of the From review the Updating the appropriate level appropriate the Updating 17. An artist’s impression of the Ulysses spacecraft. spacecraft. Ulysses the of impression artist’s An Credit: NASA/ESA -6 - - -

hood of an accidental release that results in fatal fatal in results release that accidental hood of an environment. onethe If considers likeli the that released in to beaccidentally required risk fuel this (1.5x10 0.00015% than more to risk no cancer increased lifetime mission Ulysses the associated risk with individual added culated al et (Sholtis concluded review This (INSRP). Panel Review Nuclear Safety performedvey was Interagency risk by of the the space governments. agencies and public, Asur some raised general concernsre-entry the among accident uncontrolled an or an following material radioactive highly this Thepotential 238. release of Plutonium by (RTG) generator fuelled moelectric powered was Ulysses bysystem. a radioisotope ther theand solar thesun probe aimed atstudying tific 1990 Discovery, Space by the Shuttle ascien was October in launched spacecraft, Ulysses factor. The sample. of the nature hazardous potentially by the posed risk mined) (undeter the to factor areduction representing as understood be to has value This risk. tial poten (unknown) of the probability maximum the provides only of level assurance the rather cancer was less than 1 in 100,000, the actual added added actual the 100,000, 1in less than was cancer provides a good illustration of areduction such provides illustration agood The case of the NASA-ESA Ulysses mission Ulysses NASA-ESA of case the The ., 1991)., cal highest the that -6 ). However, to be real, ------31 Mars Sample Return backward contamination – Strategic advice and requirements 32 Mars Sample Return backward contamination – Strategic advice and requirements curation facility. curation to the transport accident during an against guard to containment adequate protection transport via to sample provide and the interaction with human to reason, minimise be taken care must For this for release. accidental potential error the and human of risk the entails itself process transport the and this in handling of human use the that highlighted it to factors, be has human considering tasked with Group Study the not was While facility. curation site to the have landing from the to betransported befeasible. should level of reliability to ahigh Vehicle Return penetration any Earth ofdetect the would that systems protection, sensory potential risk in belimited might leakage detect that systems sensory release upon and entry. While tamination con exterior thereby from causing Mars, transit bepenetratedcould by amicrometeoroid during ofrisk release requirement. the consistent with magazine the encased within sample the required is that the level of assurance beable should to sensors, provide detection leak of using detection probability conditional tional the andaddi place first the to create in aseal failing previouslycombined mentioned,as the low of risk limited, are systems sensory Although example. for outgassing utilising back up system, sensory been shownhas to a be reliableorderwith to first concept that asealing conceptcontainer with along of aproven use the via level of reliability to ahigh leakage. via sterilisation not are after contaminated surfaces that ensuring and heating, re-entry as rect such means biosphere or indi by Earth’s into direct the re-entry at some point prior ofsurfaces the to sterilisation first place, the in spacecraft fromcles surfaces the includeexclusion These parti potential of be used. might of verification methods indirect only of this, 10 the to beconsistent with are often not enough indications reliable Sensory or due to re-contact at some difficult. is later date, biosphere, surface Mars from the either upon return elements Earth’s come the that into contact with of spacecraftthesurfaces Verificationof sterility of 4.7 out to be1.5x10 turned and magnitude 0.00015% than sion smaller by was five orders of - mis Ulysses the associatedwith cancer ofrisk fatal Upon return to Earth, the sample would still sample still the would Upon to Earth, return However, it sample possible magazine is the that be assured sample of Mars can the sealing Initial Potential verification methods Potentialmethods verification -6 requirement. Because Because requirement. -11 . - - - - ronment. adesert-like envi bein would impact least the and site forkey abreeding species, was the of exposure greatest (ifthe impact any) location the beif would consideration. principle, In important release an is the from 2tolocation stage 5above. any of Thus, be at could This beexposed. must organisms Earth one or event more chain, this someAt in point 5b. 1. 19): (see Figure necessary is also sequence of events following the form, a viable life risk. pose amuch form wider could a viable life whereasarea, in principle, limited to a confined very be would risk the of atoxic case chemical, the In toxic chemical(s). and/or ahighly virus-types), ing (includ entities viable biological hazards: potential two samples may from Mars contain Returned to environmental consequences 5.1 l l l consequences the a framework to approach From to release risk: 5. 3. 2. 5a. 4.

ecosystems Mars from environment different an very in Survival sterilisation spacecraftsurface due to or loss ofineffective Release containment from arise risk to environmental For a significant species, disturbance/breakdown of terrestrial of terrestrial disturbance/breakdown species, Displacement or of outcompeting terrestrial AND/OR species replicating of the Pathogenicity Dispersal/transfer organism(s) by Earth intake or following environment external the either in Replication, The sequence of events The sequence leading - - exposure of the environment of the components toexposure the of sterilisation surface spacecraft the of or Release due to failure of containment laboratory. into the material of the introduction the following act errorbe due orhuman to adeliberate human of cause a release would most the likely that assume it reasonable is past, the to in material pathogenic low. bevery area will deposition per unit even smaller) therefore and particles unsterilised (the of However, quantity besmall sample will the altitude). breaks up capsule (especially at the high if over for area contamination potential wide a quite and (possibly) first there the is second In cases, • biosphere:ple Earth’s into the accidental/deliberatefrom the sam release aMars to beinitiated exposure ways environmental for an principle, main there four are In sample. Mars the there must exist an event that would initiate an an event initiate would an that there exist must point source. Based on failure of of containment onpoint failure Based source. • • • laboratory. or from the transport during ofEscape material the Earth, vehicle duewith to to impact the heavy Damage toattached its outside surfaces, particles Mars having potentially Capsule, Entry of Earth the sterilisation full unsuccessful An (due orentry sabotage), fault to adesign A break-up atmospheric during container of the For thereopposed toas be a risk, to a hazard, In the two latter cases, the release would be a release would the cases, latter two the In - 33 Mars Sample Return backward contamination – Strategic advice and requirements 34 Mars Sample Return backward contamination – Strategic advice and requirements indirect consequence on Earth species. consequence on Earth indirect or representing new thereby resources, and have an by, in, for resources for competing settle example, they ecosystem of the equilibrium and functioning the disturb potentially would organisms These biosphere. Earth’s to the colonise organism Mars species. Earth uptake by an environment or following external the replication undergo in could organism Mars viving sur a conditions, environmental physico-chemical a new to set of cope with on its ability Depending organism(s) byEarth intake following or Replication either in the external environment conditions. these under on howinformation have they adapted to survive (), there aconsiderable is and of body on conditions Earth chemical physical and extreme in survive can organisms biological evidentis that ronment It sample. bepresent could areturned in envi not is formEarth’s that adversely by affected beconsidered must life aMars that possibility the However, conditions. Earth under surviving culty have would on Mars great diffi form existing life any that likely it very is Earth, and oftions Mars the environmental condi in greatDue differences Mars from different very inSurvival an environment Spain. Tinto, Rio of waters acidic the in thrive microorganisms Acidophilic 18. Figure Survival and ability to replicate would allow the the to replicate allow would ability and Survival - - - - of the chain of events. chain of the species a consequence as vulnerable the contact with form to come life in Mars for the potential the is the question what of raises species. This susceptible or deemed vulnerable organisms Earth rienced in be expe occur, it does will pathogenicity If Earth. on of to that life biochemistry form asimilar has life species anticipated is to Mars be greatest the if Earth scenarios. potential reflect to but rather sample, Mars the present in being organisms of such potential toany due have not chosen been examples these note that to setimportant outscenarios above. very It is havethat with placehave taken and some parallels Table examples, a few incidents Earth-based 4 lists one to approach If wants using issue the unknown. is organism Mars dispersed and replicating ing, liv of apotential pathogenicity potential The species of replicating the Pathogenicity isms. organ closecontact between through by transfer thereforeand mostis effective generally the mode concentration organism the of dilution considerable water involves and inevitably wind via Dispersal water, and wind organisms. biological or via e.g. physical forces, via may occur dispersal/transfer ofon pathogens Earth, environmental case the In Dispersal/transfer The prospect of pathogenicity arising within within arising The prospect of pathogenicity Credit: F. Perez, CAB F. Perez, Credit: - - - each step (see of event the chain Figure based. conclusion weakly is this for ones, but justification the most realistic the theimpact biosphereon to haveare asignificant likely least scenarios beanticipated the that it might on Earth, of organisms pathogenic understanding in are These outlined Table impact. 5. tal events lead tocould a major that likely environmen least most and the it possible is torisks, identify human opposed as to risks direct environmental 2010). regard to in resourcesits own (Jha, Overall, only or region using community ofcapacity alocal theresponse to enough sufficient impact overwhelm adverse event (i.e. a hazard) one an causes and that needs an to be between made distinction A clear 5.2 Table 5. pathogen Earth an of release alocal from impacts environmental major of Examples 4. Table scenarios are most likely to occur. Based on the Based to occur. most are likely scenarios which species are not ecologically important. define difficult more even is –it important economically be will and are organisms which define to difficult very is It Note: Impacts effects form/ life the of potency Pathogenic Transfer time over form life of Quantity Identification Category Myxomatosis Dutch elm disease Ecological blight Potato disease mouth and Foot BSE Economic Agent Inevitably, there are great uncertainties within within Inevitably, great there are uncertainties Therewhich is a no adequate to basis identify Estimate of the overall of the Estimate risk Criteria for minor and major environmental accidents

or ecologically important economically not are species Affected reversible effects and minor affected, species Few contamination site original from spread no or Limited available quantities small very only therefore replication, no or slow Very Early detection environmental impact asignificant have to likely Least Myxoma virus Ophiostoma infestans Phytophthora virus Aphtho Prion Likely causal agent

19) to and - - caus or, to hijack them, some cases, in mechanisms, have co-evolved to avoid body’s of many the defence 20˚C. pathogens temperatures greater Human than a cold is seldom that experiences planet other hand, on the to cause pathogenesis. Mars, colonise and beablemust to grow replicate and at 37˚C order in pathogens Human borne population. bythose the ofcases environmental consequencesSpecific are health for human 5.3 4.5. Chapter recommended in factor oftion amillion one in low, quite is Mars not reduc even the considering from entity biological adangerous by returning Chapter stated and risk posed in overall 3.6, the 2.3 have to However, be met. Chapter in discussed as will somerisk, representconditions asignificant Direct consequences Direct rabbits in two years two in rabbits wild the of 90% of deaths the in resulted France in estate asingle on 1952: release alone UK the in lost trees elm 10 million emigrated 1.5 million afurther to starvation, due died humans 1.5 million 1845, Ireland: many sacrificed thousands and disease the with animals thousand few a for ultimately responsible was restaurant a from food waste 2001, claimed UK: millions of sacrificed cattle affected, cattle of 1989, thousands From Nature of incident or ecologically important Affected species are economically and/ serious effects serious delayed, affected, species vulnerable aparticularly or species Several vectors more or by one spread Effective over amounts time increasing replication,Efficient leading to ever detection delayed Very environmental impact asignificant have to likely Most - 35 Mars Sample Return backward contamination – Strategic advice and requirements 36 Mars Sample Return backward contamination – Strategic advice and requirements microbiology laboratories, it diffi is cult to predict containment from high data performance by using or data fromlated engineering semi-quantitatively be calcu- of risk arelease the can While a release. consequence the sample, ofand the of such dling and/or return the han- a release of sample during be there that will likelihood the mission: MSR an Thanyassessmentrisktwo in factors be of will ere consequences its and arelease Modelling Mars. from originate could disease human ble of causing capa- microorganism any that unlikely exceedingly ted from person-to-person. Th esefactors make it to unable are be transmit- dosesand infectious have diseases high such and host to disease, cause animal another without microorganisms mental rare It not foris very is environ- availableon Mars. or protozoan reservoir, have which animal another also pathogens Most human death. and disease ing 19. igure F Flowchart representation of the event chain necessary for substantial environmental consequences environmental substantial for necessary chain event the of representation Flowchart Survival of Mars organism(s) YES Release of unsterilised particle YES sample or on the surface the in organism of virus/GTA-type or organisms Mars living of Presence YES re-entry Earth YES to meet vulnerable specie(s) Mars organisms disperseenough YES Pathogenicity of Mars organisms YES Replication of Mars organism(s) YES cal functions. Th functions. cal developed are normally ese models statisti- as and rate of 50%, fatality a case e.g. terms, Th in thenexpressedare numerical assumptions ese investigations. epidemiological from and literature scientifi from on the evidence obtained built are c how and it spreads. Th disease the assumptions ese need aseries of assumptions to about be made els, Tospread disease. mod- emerging the of populate an have release of been the bioterrorism the and agents cost benefithe t. e of two areas greatest interest Th to reduce to spread measure and the of infection effto the measure ectivenessinterventions usedof Th diseases. tious have ese models developed been of epidemics of infec- modelling mathematical in consequence.case worst on sample its potential and the in ence of life pres- beabout must made potential the assumptions a consequence to value be reached, of anumber order In for fashion. accurate consequences an in NO NO NO NO NO NO NO In recentIn great years, progress been made has and indirect effects and indirect direct of Risk web) food of perturbation (e.g. colonisation, effect indirect of Risk Potential risk No signifi cant risk High risk • • gens: Group for 4patho some 3and estimates Risk these Table transmissions. to secondary 6providesing lead infection initial undetected/unreported of an consequences the concerning estimates up-to-date 2012) provides (NIH-BRP, Laboratories Diseases Infectious Boston Universitythe Emerging National AssessmentRisk forreport draft the benchmark, a as organisms pathogenic highly transmissible sequence release organism. of potential of aMars the above listed thereforepoints and con to the model it of impossible any is the pathogens, to answer lack Mars of on to potential Due our knowledge • • • given is below: models in used commonly of assumptions ventions. A list inter various of efficacy butthe to assess casualties, tonot idea give of number of only possible the an Table 6. • • • • • • • fatalities public of Number infections public of Number Consequence The SARS-associated coronavirus SARS-associated The period Incubation population of Susceptibility flu pandemic of 1918 pandemic flu The 1918 – H1N1responsiblethe Spanish Virus of symptomatic of phase the Duration animals/plants it infect Can environment the Survival/reproduction in Transmission routes (aerosol, etc.) ingestion, outbreaks amplify and transmission increase ofHospitalisation patients can –hospitals rate fatality Case transmission of window Time individual per infected cases secondary from person to person/numberTransmissibility of If one wants to approach the issue using known one known to approachIf wants using issue the Consequences of secondary transmission following undetected/unreported initial infection as modelled in the frame of NIH-BRP (2012) NIH-BRP of frame the in modelled as infection initial undetected/unreported following transmission secondary of Consequences 1,000 or more 100 or more 10 or more 1 or more 10,000 or more 1,000 or more 100 or more 10 or more 1 or more Performed Simulation of Number <0.0002% 0.3% 9.1% 24% <0.0002% 0.2% 8.8% 21% 38% 500,000 coronavirus SARS-associated Percentage of simulations in which a consequence occurred - - - - <0.001% 0.02% 5.6% 36% <0.001% 4% 28% 40% 62% 100,000 1918 H1N1 Virus • • that one individual actually gets infected following following infected gets actually onethat individual not do consider they probability the infection, tial the reflect consequencesini they that an of mind in 10% of chance 10 occurring. or more fatalities total a of a less than estimate to an leads for SARS-CoV fatality estimated The case 10% cases. total 1,000 of chance a0.2% grow and would to 100 cases, total an thatoutbreak chance 8.8% estimated an Thereis to at one least contact. infection of transmitting enters have would public the about chance a38% who SARS-CoV with infected individual or any alaboratory worker model, the in used assumptions isolation. and drugs, vaccines, as procedures such mitigating instituting of effect incorporate positive the they area and Boston urban of the characteristics societal demographic and the Table given in results note the that to specific 6are scenarios. worst case potential reflect to but rather sample, Mars the presentin being organisms of such potential have to any notdue agents chosen been genic performed).of simulations sequences (out occurred of several tensof thousands con which in based number onof the simulations fatalities) public of number infections, public of of consequences somechances defined (number The figures figures presented inThe Table 6 give estimated the The Ebola virus Ebola The bubonic plague The It is very important to note that these patho these note to that important very It is When considering these figures, is it to key keep figures, these considering When the case underbase that, suggest These results bacterium –responsible bacterium for the pestis Yersinia N/A <0.001% 12% 56% N/A N/A 0.03% 18% 62% 100,000 Virus Ebola It is also very important to important very It also is N/A <0.001% 3.5% 52% N/A N/A <0.001% 17% 57% 100,000 Yersinia pestis - - - 37 Mars Sample Return backward contamination – Strategic advice and requirements 38 Mars Sample Return backward contamination – Strategic advice and requirements • include: arise could that Some questions of be required. the pathogens would with of for strategies current dealing applicability of the were a major tocase, rethink be the this If considered worst scenario. extreme case to bean biosphere, be must this Earth’s sequences the in but nonetheless able is to adverse cause conEarth life forms on to biochemistry different mentally realised. is before threat of the nature the occur spread may significant areunusual, not effects the spread. However, the limit slow onset is the and if to try taken to be andcan actions quickly fiedfairly be identi causative the agent that will most likely of rapid and it is onset, releaseof unusual are the relevant. emergency response preparation highly is and domains health public in gained experience context, this effectively.In responding a release and any consequences such of detecting effectively and release toof agent rapidly the is abiological ing react One in key strategies of issue. the another is from sample the material releasethe of unsterilised to leading potentially abreach containment in with coping over decades, been gained past has isms the organ pathogenic highly managing and handling know-how in andexperience nificant operational alone. level not is sig sufficient if highest Even the updated. larly and acknowledged regu defined, well uncertainties with sound scientifically be should scenarios These release?”. unintended of happen case an in might “What question the addressing scenarios, potential anddevelopment to workcrucial definition on the of aconsequence having biosphere,scenario on the it is it notexclude is As possiblea release to definitively 5.4 aerosolised or not). (e.g. been pathogen has the if ofmethod dispersal of the pathogenone to and exposed is quantity the depend on strongly will probability This exposure. • • Can it be assumed that the consequences the that lim are it beassumed Can ited to one or afew species? Are currently availablebiocides effective? currently Are detected? detected? How presence form(s) the can life of the be If the Mars life form has an unknown, funda unknown, form an has life Mars the If From effects management the position, a crisis if prerequisite, it aclear is at containment While Being prepared Being ------• • • • encompass: they that and level local at the and possible as soon implemented be to as basis. on aregular updated and reassessed have reviewed, be to will they development and their in required be will expertise and of means level the appropriate Therefore, consequences. potential of limitation or containment gation, miti of efficiency the optimising in elements key be will strategies response and monitoring these. from developed are strategies response that and investigated, and defined release) clearly are undetected (including scenarios release potential recommended that it is prevention strategies, current to addition In response. emergency and health of public thefields in experience from available benefit should and importance of utmost is material of Mars respondarelease to capacity Building narios developed as well as of their associated associated of their as well as developed narios effective warning procedures warning effective anomalies of detection rapid indicators pre-defined of observation analysis, resistance and mitigation procedures mitigation and resistance analysis, It is critical that such strategies are designed designed are strategies such that critical It is The relevance and significance of the sce the of andsignificance The relevance - - perceptions however, of risk, tend to be compressed people’s Lay measures. statistical inherent in risk, tendthe toto low reflectcompletefrom high range, perceptions their fromof those non-experts; cally systemati differ of judgments often risk Experts’ Experts versus non-experts newsfrom media. the often receivedisproportionate also attention risks overestimated non-fatal Notin forms. surprisingly, common also are and at atime, one or afew victims claim events usually that concern less spectacular whereas risks sensational underestimated matic and crashes)(e.g. air accidents, nuclear tend to bedra overestimated Thus, risks or recall. to imagine easy of it relatively are or instances common if likely as judgement perceive heuristic event an this who use availability. cognitive heuristics: judgmental ceived be related can risk to one most of general the al by et Fischhoff argued As quantifiable. predictable and of both tion is risk percep but their assessments, that probabilistic show way the people that from perceive differs risk (seefacilities forSociety, 1983). example Royal (see 1995) for example nuclear Kolluru, power and space as exploration such technologies programmes context of the new in analyses to conducttools safety workof probabilistic use followed increasing the Starr’s Lowrance’s and Both others. acceptable than why some were technologies helped less to explain His work influential. also of was risk acceptability Lowrance’s (1976) of the work on determinants Starr’s (1969)with work voluntariness. on and risk late 1960s, the in started risk on perceived Research l l l experts and public general the between differences Perceived risk: 6. Slovic and colleagues (1979)Slovic colleagues and were to first the . (1978) per biases in People People - - - - lay people’s by a influenced variety are judgments whereas statistics, one as of judging primarily task see the perceived experts it though risk, seems as asked about When statistics. mortality annual with correlated not are highly and as range, into asmaller to both factors. Thus unknown, new risks with cata with risks new unknown, Thus factors. to both potential. catastrophic by defined ily and involuntariness by to alesser extent newness, and and to exposed those unknown characteristics by the determined tor primarily was first fac order The factors. higher by two explained severe unfamiliar, uncontrollable, potentially catastrophic, to science, or to those exposed unknown involuntary, as such end on characteristics high-risk extreme power nuclear as such scored hazards closeto the showed and less acceptable that hazards, various Fischhoff these hazards. of relatedcharacteristics to specific ability accept possible limited the of are causes the What acceptability Risk public. general the by ception below,factors discussed however, riskper impact presented The hazards of many the to them. with, experience and about, knowledge limited given their one about expect, good as is would as tasks these in adequate order at rank level. People’s performance of lay quite people estimates are generally Risk risks. the of ordering not do of and affect risk estimates to areabsoluterestricted generally effects these that however,of It factors. other to needs bestressed, delay of impact delay and dreaded and of some technological hazards? This can be can This hazards? of some technological et al et severity of consequences, dread of consequences, severity . (1978) “risk profiles” of assessed . Overall these ratings could be could ratings these . Overall . Thesecond factor primar was Controllability contributed contributed Controllability unknown to science unknown , and and , - - - - - ,

39 Mars Sample Return backward contamination – Strategic advice and requirements 40 Mars Sample Return backward contamination – Strategic advice and requirements gr 20. F igure (Finucane al. et risks particular with on associated positive negative and drawing feelings world, by dangerous sometimes and plex, uncertain effi and to navigate quickly a through com- ciently people allows that mechanism orienting –an ristic’ fi identifihas research this ndings, ‘aff an ed ect heu- other associative Among networks. in phors linked concrete meta- in images, encodes reality system aff holistic, is system intuitive. and ective latter e Th experiential the contrast, words In numbers. and symbols, abstract in encodes reality and deliberative and logical, analytic, is system processing rational 1994). system” (Epstein, Th experiential driven e emotionally an and system arational processing: of modes information interacting parallel, “two ing developments theoretical and distinguish- empirical Loewenstein’s of work broader models. these part is emotions (e.g. ignored anger, fear) in were typically positivegood or bad, or negative feelings) and decision. Affto at arrive acalculated ect (a person’s of possible outcomes likelihood the and desirability the both assess people that analytically assume Thquentialist”. typically choice ese rational models “cognitive are conse- and or risk uncertainty under ofnoted majority vast theories of the choice that (2001)Loewenstein one was researchers of the who intuition and affect of role The genetics. human and biotechnology as such areas developments in more recent technological about be made point can consequences. Asimilar catastrophic of potentially controllability the as concerns about by such their issues determined are people’s that clusion was of fears some technologies rejectionand of specifi c technologies. con-main e Th acceptance predict future reactions public and stand helpedperception risks to under- of technological tendstrophic toless acceptable. potential be seen as Overall, results of these early studies on people’s studies early of these results Overall, • • • Risk assessment Risk assessment, risk Risk and management assessment, the public. Characterisation Quantification Identification • • • Societal and political processes , 2000). Trust Equity and procedural justice Transparency • • Risk management Risk mitigation Risk communication eff of importance equity-relatedthe illustrate ect munity is confronted with a risk, while the benefi the while confrontedarisk, is with munity ts com- to below tends local when the acceptability Risk–benefi Local important. also are distributions t process helps more to risk make acceptable.making decision- of the research shows transparency that of extensive body processes. An decision-making Th alsorelated societal to risk is of e acceptability Social context (Slovic risk dangerous al extremely et aproposedthat repository nuclearwaste an was view the resultedin which of dread, strong feelings cancer,mushroom cloud) the and death, as evoked ‘nuclear (images repository’ waste such ated with associ- public American the images ofmany the al (Slovic et ‘charge’ emotional positive a strongly or negative carry that images perception risk in attemptstive to identify images representations. Th symbolic and study of e ec- aff perceptual sentation or content cognitive including images. about specifior negative feelings or ideas c objects, risk. aff between tionship and perceived imagery ect, role on the Research of afftheinvestigates rela-ect risk and images Affective Public reactions or the anticipation of the nature of anticipation reactionsnature of or the the Public aff mitigation. andrisk risk communication ect involved. risks of the Th ese should public reactions perception acceptability the the both and i.e. tions; aff process decision-making all the ect public reac- 1999). of Perceived transparency and equity, trust al et (Siegrist developments nological new tech- associated reactionspublic with to risks factor in of this importance pointat the of studies been researched also has extensively, a variety and (e.g.issues Van Dear,Horst, der 1992). 2007; Trust Not-In-My-Backyard so-called of this ( awhole. Numerous as examples forare country the Af trefers to aperson’s positive good or bad, c e ff A Imagery Imagery refers to all forms ofrepre- mental refers to all • • reaction Public Risk acceptability Perceived risk ., 1998).., For example, ., 2000; Slovic, Slovic, 2000; ., ., 1991). ., NIMBY ) it is difficult to predict public reaction to possible possible to reaction public to predict difficult it is biosphere unknown are terrestrial the into form life Mars of apotential release unintended an this situation. some at least). countries to nourish It important is agencies (in its regulating and nuclear industry the to seems apply as to lack of trust from astructural not do suffer ESA and NASA general public. the by risk associated are with that new facilities siting of case the in to be less prominent than likely are issues equity possible and the risks how with to deal process decision-making of about the transparency section, this of paragraphs final the in described context social the with we start If communication. risk and mitigation risk for management, risk of anumber concrete in graphs results suggestions the previousin para literaturesummarised The 3. 2. 1. include:factors These public. (and more less acceptable)being worrying to the Bennett by defined features risk the of many contains sample return aMars actuality, In asample return. possible associatedwith risks perceptiontheincrease popular of most definitely theories are of such to effects The idea. this with However, not do of agree scientists majority the eye. public the in pathogens cept of extraterrestrial con keeping the from humanity, space to infect may emerge SARS as such micro-organisms genic of patho arange that postulated Wickramasinghe and Hoyle 1908). Later (Arrhenius, Arrhenius proposed was of by Svantetheory Worlds fromthe past for War years, 100 of films theand been atopic literature has for popular humanity to destruction and death fromisms space causing The conceptmicro-organ macro- or of hazardous MSR of context the in risk of Perception interdependent various the rises processes. Figure programme. communication risk more amore extensive assessment risk and elaborate assessment. A more apprehensive warrants public the risk of nature affect also reactions should these 7. 6. 5. 4.

As inescapable by taking personal precautions personal inescapable byAs taking To voluntary rather than beinvoluntary Given the fact that possible consequences of consequences possible that fact Given the responsible sources statements subject to contradictory As from To by bepoorly science understood dread To particular aform arousing of threaten death sources To natural from result man-made, rather than To arise from an unfamiliar or novel source To unfamiliar from an arise and beyond. The The beyond. and Strain Andromeda to the et al et 20 summa 20 . (2010) as as (2010) . - - - - - possible consequences of an unintended release. unintended of an consequences possible the considering approach when adopt acautious to best it seems uncertainties Giventhese forms. life of Mars escape possible the with ple associate peo risks tothe relation their also and images these monitor to advisable be but it would ing, is reassur This waste. toxic and energy nuclear as such hazards technological with associate to people tend those than valenced probably less and clear-cut less are forms life Mars with ates associ public general the that Images risks. Figure 21. Poster of the 1953 movie War of the Worlds the of War movie 1953 the of Poster - - - 41 Mars Sample Return backward contamination – Strategic advice and requirements 42 Mars Sample Return backward contamination – Strategic advice and requirements Space, including the Moon and other celestial bodies, bodies, celestial other the Moon and including Space, of1967) Outer use and provides “exploration that Article 1997). (ICJ, the of whole mankind” for also but States not only for the environment, for to respect it attaches that significance great stressed “the 1997 court the In to the environment”. relating law international of of the part now corpus is control national beyond of or areas of States other the environment respect control and jurisdiction their within that activities obligation of to of the ensure States general existence (ICJ, 1996) weapons ICJ states: of “The nuclear use or (ICJ). Justice of Court International been by recognised the 1992), have principles which into legal later turned Development, and Environment on Declaration 1972; Rio Stockholm, Environment, Human the United of(Declaration the Nations Conference on have been elaborated way by the of declarations law, principles some environmental international In the Earth and of Outer Space contamination 7.1 apply. resolutions, and treaties UN law space the and law,tional including concerned, are general interna space as activities far Outer Space as and In liability. and responsibility concomitant with environmentthe of Earth, the to changes adverse or preventto contamination obligation there an is states that mission ple return asam framework surrounding current The legal l l l Mission Return Sample of aMars aspects legal and Regulatory 7. ronmental issues resulting from space activities. from space activities. ronmental resulting issues Obligation to Obligation prevent pollution/ In space lawIn envisome provisions with deal opinion its 1996In advisory

1 of Outer Space the Treaty (United Nations, Legality of theLegality threat - - - including the Moon and other celestial bodies, and and bodies, celestial other the Moon and including “ to reference A special States. by made is all use and free be explorationfor shall They of mankind.” all shalland be province the development, scientific or of economic degree of their irrespective of countries, all in interests the and the benefit for out shall be carried of organic life. of organic indication of any as well health, as lifeor human endanger could which the Moon, including Space, Outer in discover they phenomena ofany munity, com scientific the the international and public as well “ to UN promptly the inform reference for States Parties obligation to made an is nation (Uniteding Nations, 1979). its Article In force in is butany not has spacefar by been ratified mission. MSR an in part taking sures mea appropriate adopt where necessary, shall and, matter of extraterrestrial introduction the from resulting Earth of the environment the in contamination harmful conduct explorationavoid to as of so their them and bodies, celestial Moon other the and including Treatyto the shall of Outer Space the Treaty: IX Parties “States Article investigation such in operation co- international encourage shall and facilitate States The agreementMoon enters into it moredetail; This provisionThis a precise sets on States obligation The most relevant provisionin may be found freedom of scientific investigation in Outer Space, Space, Outer in investigation scientific of freedom for this purpose.” for this “ pursue studies of Outer Space, studies pursue adverse changes adverse changes also and .” Secretary General as as General Secretary 5.3 a - - - This artist’s conception of Mars Sample Return mission shows the entry, decent and landing sequence onto Mars. onto sequence landing and decent entry, the shows mission Return Sample Mars of conception artist’s This 22. Figure Convention Article Liability time; or in amount eitherin ceiling any conventionble this under (absolute without liability lia spacecraftis the launched State having the that it may consequencesmental be considered on Earth spacecaused by the object”. asampledetri has If 1971), for State liable is “damages launching the victim. the totion indemnify thereobliga maylaw. be an of damage any case In beresponsible would to international IX according Article violates the Statewhich not is tion fulfilled, Outer of Space the Treaty. IX obliga Article this If in contained obligation the provision especially is For relevanttreaties. the aspace sample return Outer Space the law international including with conducted is accordance in activity the sure make The State should a“national is activity”. activity State this by for the which continuously supervised and beauthorised of must aState and sibility respon the Outer Space under is in activity every Outerof Space the Treaty, VI to Article According of States 2 7. Under the Liability Convention (UnitedUnder Liability Nations, the Responsibility and liability liability and Responsibility 1 – loss of life, personal injury injury personal 1 –loss of life, - - - - - Outer Space Treaty. Space Outer of the IX forpute violation of mechanism Article - of dis settlement usual law the and international general under act illegal for an versus responsibility Convention, Liability the under commission a claim to have of constitution the possibility the and bility not is same: absolute the lia responsibility/liability of nature the the and tlement ofmechanism dispute Outer Space Treaty). the set that difference is The of the IX law of(Article violation international in be Convention, it still nevertheless would Liability object”. space the perhaps would age not be considered “caused as by dam the latter, much point is more the uncertain; laboratory. the In Earth-based of from aleak an case for the example, and, capsule, of the re-entry at the place object”, event acontamination taking as such intergovernmentalof international organisations). or property or juridical, States or of natural persons, of to property or loss ofor orimpairment; damage “caused by aspace object”, required as by the Convention not is directly damage the because maywhich be considered “caused as by a space If the State is not liable under the Liability Liability the State not is the under liable If damage be between must made A distinction Credit: NASA/JPL - - - 43 Mars Sample Return backward contamination – Strategic advice and requirements 44 Mars Sample Return backward contamination – Strategic advice and requirements activity are deemed are Parties”. “Consultative activity States involved those State;open only the to every in are not discussions Protocol. These Madrid the and Treaty Antarctic the under Parties Consultative cooperation among of Antarctic lines the along responsibility and liability. States’ consequences onpossible the the of damage of and to adopt measures obligation these of their States involved the case, any beconscious must In • • be: could They beused. should of rules be or would what noteither what kind they indicate does but measures” “appropriate adopt to obligation preventing contamination. to “adopt appropriate of for purpose measures” the orderby States in to implement obligations their Various may be accepted obligation levels of legal preventing damage value to legal some measures 7.3 • • • • use: to instrument The legal • Prevention measures Prevention – As a code of acode conduct– As rule acompulsory – As order legal adomestic within Implementation texts of these version)conduct its COPUOS–STSC and of code (see: value compulsory out legal EADC Convention) Water Ballast IMO the with analogous and COPUOSUN by drafted agreement for instance or (treaty regulation compulsory International of damage case in Cooperation States to prevent between or damage problems any – Of possible– Of hazard activity the – Of involved) the States Statesto Notification other or (all International code of code conductInternational accepted but with agreement States involvedan between accepted by regulation compulsory International A cooperation mechanism cooperation A Outer Space of the Treaty IX creates an Article The necessity/utility to give The necessity/utility may be set in place may besetin - 1. return sample and exploration Mars 8.1 l l l recommendations and findings Group Study 8. 2.

The past fifteen yearsfifteen anThe past enormous have shown and confirm key results. confirm and to repeat experiments coveries ability the and - dis unexpected potentially and unknown the with dealing in greater sample, the flexibility on perform analyses complex and experiments (but not restricted to to): including ability the desirable is for several reasons a sample to Earth returning done by surface, robotics Mars on the questions may be answered by in-situ some Although exploration of Mars. human any precursor to essential been deemed an also has Sample Return AMars insights. astrobiological new geophysical and geological gain history, and its and climate, and itsvolatiles of Mars, tory - his the greatmake progress understanding in theof asample, study researchers could Through mendous. aretreMission offeredReturn Sample by Mars perspectives context the this in discoveries and led always to has future shows discovery that scienceof history The generalpublic. the but also produce notfor science only technology, and will benefits vast the it attention to facilitate extra requires awhole. amission Such as of Mars ing understand the advances in promise dramatic exploration, it Mars as would in priority highest been deemed has the Sample Return AMars life. environments or extinct amenable for extant for search the in and system, solar our in planet most Earth-like the of Mars, interest in growth studies studies - - 3. optimisation and Principle Precautionary Uncertainties, 8.2 5. 4.

potential Mars organisms can only be speculated be speculated only can organisms Mars potential about made assumption biology’.‘Mars Any there no is and known been found, has Mars on life or extant far,So no evidence of extinct frame of an MSR mission. Adapted spe to mission. the MSR of an frame controlemission approach asuitable is the in Technique (BAT) field pollutant of the in used concept the that Availableappears of clear Best it strategies, regard to optimisation With mission. MSR posedtions by an the condi with well conceptaligns This harm. presents no appreciable activity the that of risk proponent the shows unless activity of the harm of risk the available requirements to minimise besubject to technology best should harm cant for signifi potential presentthat uncertain an Principle Precautionary conceptThe of Best Available Technology consequences of the of arelease. magnitude andof probability)the nornature definition frequency (in classical the or harmless harmful be sample could the that mate aprobability itesti not is possible touncertainty, definitely Therefore, mission. a such levelMSR with of posedment by an of risk of contamination the - for assess areal major allow would factors that conclusions fromreached definitive being on preventsuncertainty, knowledge, lack or of This conditions. environmental and geology of Mars’ understanding and ecosystems) knowledge with analogous in biology (especially on Earth of knowledge life upon by combining instructs that activities activities that instructs - - - - 45 Mars Sample Return backward contamination – Strategic advice and requirements 46 Mars Sample Return backward contamination – Strategic advice and requirements developed to meet them. havetechnology, would new technologies to be requirements available not beachievable with these Should magnitude. and probability release the for requirements adequate mend and recom to define to set a limit important (at areasonable cost) yet it seems used, are release minimised. is this of magnitude the also release and unintended of an probability the that orderin to guarantee mission MSR adaptedan specificities toof the andsation concept a benchmark as used is Available Best the Technique (BAT) optimi Group Study thatESF-ESSC recommends The RECOMMENDATION 3: Worldthe Organisation) apriori. Health Group beappliedshould 4(as to Risk by defined GroupStudy sample aMars recommends that ESF-ESSC the advice, past accordance with In RECOMMENDATION 2: particles. Mars release of potential unsterilised the ering PrinciplePrecautionary applied is when consid Available Best recommends the Technology that Group Study ESF-ESSC the mission, MSR of an aboutas public perception frame the of riskin biosphere, well as Earth’s into entities the such consequences potential the of and releasing ties about putative enti biological Mars unknowns and uncertainties many the Considering RECOMMENDATION 1: developed to meet them. have would be to technologies new technology, requirements available not beachievable with these Should magnitude. and release probability the for requirements adequate recommend and to define set alimit it seemsimportant (atable techniques areasonable cost) used, are of arelease. such magnitude the release but also unintended an of probability the not only orderin to minimise operational conceptsand (at areasonable cost) technologies best of the use the for mobilising aconcept such mission, allow MSR would an in and involvedoperations systems the of cificities BAT only implies that available techniques available techniques BAT that implies only However, avail that BAT implies only while - - - - - 6. 8.3 7. 8.

•  genes to be free living in an environment an other in genes to be free living of number minimum the with a coccoid cell • • particular: In value. this themicrobiology field of invalidated in findings review on recentliterature developments and autotroph (250±50 extensive cell nm).living An for size afree- minimal estimated onbased the limit (0,2 size particle The original mission. MSR an sidered when designing appropriategiven an is size to be con constraint a than larger of particles containment that ing approach the with adopted 1999 since confirm Group Study concurs ESF-ESSC the Overall, µm. to 0,08 ofsize 0,17 a has 2, type stranded-DNA porcine circovirus environment. amarine in rates transduction previously reported for viral than higher times rates amillion more are than itGTA nowand is that estimated transduction replication porate host of genes any the during it believed to is be possible for GTAs to incor manner, this In host of lysis cell. the in resulting without archaea, and bacteria unrelated netically phyloge including hosts, transferred to different be capsidhost can genome which into a viral incorporateable to segments of randomly the (GTAs) agents are transfer gene Furthermore, to have belikely viruses. also would they Mars, forms on life there wereif that follows Earth-like so it on Earth, of life domains from all organisms arepresumed to be associated with Viruses µm. 0,2 but greater than avariable length with 0,1 have could less than shaped a cell width of approximatelydiameter 0.15–0,2 cell host have would a minimum aliving than On particle size particle On   isolated after ofmeltedprefiltration isolated after ice core Some between of (length 0.12–0.20 μm diameter The through a0,1filter µm through The µm) 0,84 0.37 and 0.15–0,17 100 1and µm) between (length µm Furthermore, it is believed that theoretically theoretically it that believed is Furthermore, The smallest observed virus, the single- the observed virus, smallest The

bacterium rod colony-forming

shaped µm; GTAs are in the range of 0.03 range GTAs the µm; in are Thermofilum

archea units

P. ubique P. has a diameter of adiameter has of bacteria µm. Arod- µm. has a cell a cell has µm) was were µm µm - - - -

10. 8.4 9.

GTA-type entities. and biosphere virus-type but Earth’s also on the consequences having considered potentially as are entities biological free-living replicating GroupStudy recommends notself- that only ESF-ESSC the on this, out.Based not beruled can organisms Earth to interactwith ability GTA-type and entities’ virus-type on Mars, forms life there wereconsiders if that, Earth-like producededge recent Group Study in the years, new knowl However,entities. mind in bearing biological replicating associated with those ily primar are to Earth materials of Mars return intentionalfromthe arising effects large-scale conclusions from (1997, reports NRC 2009) that the Group with Study ESF-ESSC concurs The RECOMMENDATION 4: forms. possible the escape life of Mars with associate people relation risks to the their also and images but it be advisable would to monitoring, these is reassur This toxic waste. and nuclear energy as such hazards technological to associatewith peopleprobably those tend less valenced than formsless are clear-cut life and Mars ates with associ generalpublic the that Images risks. topublic to possible reactions predict difficult biosphere it is terrestrial into the areunknown form life release Mars of apotential unintended onstrated to bezero. be dem cannot but still negligible, almost and be considered can entities lower to be far type GTA- and posedrisk bypotential virus-type the requirements, and replication specificities their considering organisms, self-replicating appears risk to below for free-living this if that to below, but not is demonstrably zero. It adds biosphere form appears life Mars by areturned Earth’s the on effects for large-scale potential the clusion (1997, reports NRC from the 2009) that another con with Groupconcurs also The Study Given possible that fact consequences the of an Public perception ------11. of assurance 8.5 12. developed. groups of stakeholders are individual with act inter recommended is to effectively tools that whole the process. It throughout to be crucial mission MSR to an relating uncertainties and risks benefits, about accountability, munication GroupThe Study considerstransparent com RECOMMENDATION 5: Mars particle shall be less than one in amillion. one in beless than shall particle Mars hazardous of release of apotentially probability Group Study recommends the that ESF-ESSC the levels, international and at national the adopted and established on standards Based RECOMMENDATION 6:

level of assurance for not releasing an unsteri forlevel not an of releasing assurance Therefore, sample. ofnature the the required hazardous mined) posed potentially risk by the representing areduction (undeter factor to the as to beunderstood has value this and risk, tial (unknown) of the probability poten maximum providesthe only level assurance This of ism. organ a Mars with Earth the contaminating for level not the of as not assurance same the biosphere into the particle is unsterilised an ing The required forlevel not assurance of releas consequences hard are to that estimate. management of with risk for in excellence ards stand international appropriate with line in and is particle Mars unsterilised hazardous tially for release of the apoten amillion) one in than level (lower assurance current it the appears that positionsthe adopted level, international at the with applied line worldwide in and regulations and From guidelines review current of the the risk. acceptable not is to equivalent an particle lised On the required level required the On ------47 Mars Sample Return backward contamination – Strategic advice and requirements 48 Mars Sample Return backward contamination – Strategic advice and requirements Based on recommendations 1to 5: recommendations on Based 8.6 13. And, if yes: if And, any circumstance. 0,05 than larger particle unsterilised single of a The release • • to determine: experts national groups of inter reviewed by interdisciplinary from design) have would to be independently achievable at areasonable cost. lowest the is size been demonstrated this that it that has systems-level assuming adjustment, tolerable beconsidered can a potentially μm as of up to 0.05 particle unsterilised of asingle non-release releasethe the of a particle, such for level overall out of the assurance decreasing 10 than less be shall environment Earth’s the into released of 0,01 particle unsterilised single that a The probability RECOMMENDATION 7: ticle size potentially released (as potentially planned size ticle

  standing on minimum size for size entities. biological on minimum standing under current may our shatter mechanisms and entities discoveries of new agents, future that overslower 15 past pace the than years. beat a possible, indeed is it will this and future, the decreases in microorganisms or free-living GTAs for size viruses, minimum expected the (especially genomics), if that oneexpect can techniques and knowledge current on our Based biosphere. Earth’s the impacting potentially as GTA-type and entities given virus-type to Mars the considerationis this driver behind main The requirement. decrease size of the sents adrastic The recommendation aboveput forward repre taking whether cle can beconsideredcle can tolerable. as release of the whether aparti such discipline, relevant other any microbiology, and virology astrobiology, developmentsof fields the in achievable at areasonable cost, Implication for design In such a case, the actual maximum par maximum actual the a case, such In If the size requirement size bemet with the cannot If However, no-one can discard the possibility However, possibility the discard no-one can

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- - 14. 8.7 basis. re-evaluated are onreleased aregular particle of size maximum and ues on level of assurance Group Study recommendsESF-ESSC val that the adecade, more last than will mission MSR (ii) and an time, tothe curation, from design perception risk as evolve can at a rapid pace over (i) that knowledgeas Considering well scientific RECOMMENDATION 8: reassessed and updated on a regular basis. updatedreassessed on and aregular response be and should strategies Scenarios • procedures • effective warning • rapid of detection anomalies •  encompass: they that and level mented possible local at soon as the and as to beimple designed are strategies such that are developedstrategies It critical from is these. that and responseinvestigated, and defined release) undetected ios (including clearly are release recommended scenar is potential that prevention to current it addition strategies, In and emergency response. of fields public health the upon draw in should experience available and of is utmostimportance material Mars to capacity respond to a release of Building RECOMMENDATION 9:

 tation of potential consequences.tation of potential limi or containment mitigation, the efficiency of the optimising bekey elements in will strategies response and associated monitoring of their as thedeveloped scenarios as of well significance release?”. unintended of an The and relevance happen case in might question: “What the ing developmentand address scenarios, of potential biosphere, to work it crucial definition is on the consequences having release scenarios on the exclude it not is possibleAs to definitively analysis, observation of pre-defined indicators Accompanying measures resistance and mitigation procedures - - - - - 15. process. relevant possible the soon as stakeholders as in be gathered availableshould to made the and information Such entity(ies) to Earth. returned biological Mars about potential assumptions and and scenarios refine elements to define be key will information access tohaving this sampleand tocontext Mars ofbereturned the physical and geochemical on the Information RECOMMENDATION 11: open are toand representatives countries. of all areset level up MSR atinternational by the an benefits and raised of risks issues the social and ethical to dedicated mechanisms that mended involved It recomthose is programme. the in beborne than setof bycould countries alarger release unintended from an sequences resulting con issue, of the nature global the Considering RECOMMENDATION 10:

istics as Earth life in similar settings. similar in life Earth as istics develop could someand character same of the life Earth sources as energy same the use likely form will on Mars given sample, alife the that in physiological groups exist of could microbes that potential the for information constraining cal be criti sample will to Mars of be returned the physical and context geochemical the general, In - - - - 49 Mars Sample Return backward contamination – Strategic advice and requirements 50 Mars Sample Return backward contamination – Strategic advice and requirements Duda, V. I., Suzina, N. E., Akimov, V. Akimov, E., N. N., V. Suzina, Duda, I., Guide to safety and and to safety of (2004). Europe Guide Council (2002– on Space Research COSPAR –Committee Dear, M. (1992).Dear, M. Overcoming and Understanding Comolli, L. R., Baker, B. J., Downing, K. H., H., K. Downing, J., Baker, B. R., L. Comolli, Center Control forCDC–US (2008). Disease R., Belas, C., Pennington, Wang, K., J., E. Biers, Hauser, J., G. Dick, LJ., R., L. Comolli, J., Baker, B. Tolerable Safety (2008). Aviation A. FAA Azevedo, (1908). S. Arrhenius, The the Worlds in Making: (1993). Pace,N.R. and K.D. Clements, E.R., Angert, W. Brazelton, J. Baross, and J. E., R. Anderson, References Alphaproteobacteria. Alphaproteobacteria. class to the belonging ultramicrobacteria development and of soil cycle organization (2007). Ultrastructural M. A. T. Boronin, and Z. Esikova, T. R., Oleynikov, N., R. Abashina, S., Dmitriev, V. B., Vainshtein, M. V., E. Barinova, 2008, and March 24, 2011. 24, March and 2008, 20, July 2005, 24, March amended as 2002, quality assurance for organs, tissues and cells and tissues organs, for assurance quality 2011). edition. Planning Association Planning of the American Journal Syndrome. NIMBY the 3 239–241. 219,2: article 1–16. ISME J ISME archaeon. of anovel,ecology ultrasmall and structure of the analysis dimensional J. F. Three- Banfield, (2009). and E. C. Siegerist, Facilities Healthcare in Sterilisation and Disinfection for Guideline Microbiol Environ. Appl. bacterioplankton. marine genes in expressionand agent of (GTA) gene transfer (2008). F. A. Chen, Occurrence M. Moran, and 107 USA Sci. Acad. Nat. Proc. Archaea. uncultivated ultrasmall, Enigmatic, J. F. Banfield, (2010). and L. R. Hettich, C. N. VerBerkmoes, L., M. Land, D., B. Dill D., Hyatt, 2008. 18–19 of Corps Engineers, US Army and March Commission Regulatory Federal Energy Energy of US Department Bureau of Reclamation, Interior of the US Department by the organised Workshop on Tolerable Estimation Risk Principles Risk Row. of the Evolution Nature bacterium. largest The ( Microbiology in Frontiers biosphereviruses? by subsurface affected (2011).A. deep of the genetic landscape the Is : 159–167. : Planetary Protection Policy Protection Planetary . Presentation given to the . 74 . , 58 Microbiology : 2933–2939.: : 288–300. : . New York: & Harper Extreme Microbiology Extreme : 8806–8811

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Johanne Martinez-Schmitt, AdministratorJohanne Martinez-Schmitt, Karina Marshall-Bowman, Junior Science Officer Nicolas Walter, Senior Science Officer Staff Support ESF ESF-ESSC Study Group composition Group 1:Annex Study ESF-ESSC Jean-Pierre Erko Mika John Petra Hervé Armel Joseph Jim Allan John Walter First name Swings Stackebrandt Salminen Rummel Rettberg Raoul Kerrest Fragola Bridges Bennett Baross Ammann Surname Committee, University Liège European Space Sciences director DSMZ Former Welfare and Health for Institute National Carolina University –East (PPP) Liaison Protection Planetary on COSPAR Panel DLR Mérieux Jean P4 Inserm Laboratoire Brittany Western of University Valador Inc. Surrey of University Microbiology Services – Agency Protection Health of Washington University Global Risk Forum Organisation Liège Paris Helsinki Greenville Köln Lyon Vannes Herndon Guildford Salisbury Seattle Davos Town Belgium France Finland USA Germany France France USA UK UK USA Switzerland Country 57 Mars Sample Return backward contamination – Strategic advice and requirements 58 Mars Sample Return backward contamination – Strategic advice and requirements • • • • • StatementConsensus • • • • • • • • • • • List of participants and Recommendations Meeting Consensus Statement 9–10 2012, January Berlin, Germany Workshop Perception Risk statements recommendations consensus and participation, workshop 2:Annex – perception Risk civil security). civil required approach (e.g. response procedures in reaction the is preparedness fast and unknown; the Prevention with to not deal is enough one go. in arrive sample will incremental –the not (if be about biology Mars any) will development knowledge nanotechnologies, and biology for synthetic Unlike organisms. virus-type but also organisms of self-replicating size account the not only into bereconsidered should size particle taking Th unsterilised ethe on recommended constraint respond material. release to of the hazardous operations to strategies biosafety and agents, pathogenic handling on as side such issues However, signifi knowledge beengained has cant hard is to reachconsensus harder to justify. and biology, on Mars expert there and no are experts Ththerefore, us, known to ereis no biology’ ‘Mars Nicolas Walter –ESF, France nds Th a e Netherlands l Space Agency, –European Gerhard Kminek r e –Northwestern University, Zoloth Laurie h USA t Canada e of Canada, Agency Health Public N WagenerStefan Lab, Microbiology –National e Th Joop Van –University of Amsterdam, Pligt der Germany –University of Stuttgart, Piet Sellke –TechriskPeter Mani Switzerland GMBH, Joseph Fragola –Valador USA Inc., Switzerland Consultant, ThEpprecht Risk omas Independent – MédecineFaculté de Toulouse, France Cambon-ThAnne INSERM-U, – omsen Switzerland Forum, Risk –Global Walter Ammann Sample Return Requirements Return Sample Group Study on Mars ESF-ESSC Committee Sciences Space European of utmost importance. In addition to current pre- to current addition In of importance. utmost to capacity respond to arelease event is Building RECOMMENDATION 2 • tive approach: bedemonstrated tocannot bezero. scientifi the among c community. However,risk this reached has consensus argument this years, past low. form very are life Mars of Over apotential the introduction from the resulting risks the that made environment Mars been the has ofand biology edge knowl- current best on based our A strongargument RECOMMENDATION 1 the mission. the Th phases of is recommendationall should apply to • • • • • • • • dimension is considered appropriate. considered is dimension at one least agiven in size than larger particle Mars forunsterilised release of the an million) level a one (lower in assurance current than the its. t fi e n e b potential as approaches well as strategies, and communication risk managementrisk and It to beconsidered has alone. with together element not does an stand is that Risk to consider.characteristic eff of the Reversibility important an is ect real. are acceptability diffCultural erencesrisk perceptionin and opportunities. lost may in mission result MSR the undertaking to tremendous; not from useful range that researchMars may benefi yield outcomes cial trust. to wholegain the process crucial is throughout communication targeted and Structured have explained; and listed to beclearly Threlease organisms. of Mars uncertainties e be considered potential when considering valid e Th trust: to gain communication) crucial is approachA transparent (including vector. beapotential still could planet ameteorite from Mars, from returned are the presented option. Even avalid no samples as if biosphere be cannot Earth’s the in organism zero respect, Mars to risk release apotential this never can bedemonstrated to bezero. In Risk Hence, it recommended is to adopt aconserva- approach cannot ascientist’ Iam me ‘trust egies. response release and scenarios strat together with basis, re-evaluated and on aregular determined are of size areleased particle maximum and ance it recommended is level on the values of that assur one more take decade, than will mission MSR the evolve to curation, from design over that, and time perception risk and Given knowledge both that RECOMMENDATION 5 countries. level open are national to and representatives of all areinterthe set MSR up an at by benefits raised and risks of issues the social and cated to ethical fora and dedi recommendedis mechanisms that involved It those programme. the than in countries be borne release set of by could alarger unintended Potential negative from consequences an resulting RECOMMENDATION 4 (e.g. map). arisk groups be developed should individual interact with whole the process. Toolsthroughout to effectively crucial is related MSR to an uncertainties the and therisks benefits, the covering accountability, the possible. soon as as be involvedshould process the of governance risk in and agencies’relevant staff community scientific the consequence, society, key stakeholders, the civil Committee’s governance risk a As framework. RiskGovernance International the by defined as ambiguity, and complexity,by their uncertainty characterised are MSR from an Potential risks RECOMMENDATION 3 relevant. be highly preparationand emergency for response an would domains health public in the in gained Experience • • • • level encompass: and local implemented are egies possible soon at as the as and strat such that developed. are Itstrategies critical is and response defined release clearly are scenarios vention it recommended is strategies, potential that statements recommendations consensus and participation, workshop 2:Annex – perception Risk analysis, resistance and mitigation procedures mitigation and resistance analysis, procedures effective warning anomalies of detection rapid observation ofindicators pre-defined In this context, transparent communication communication transparent context, this In - - - - - 59 Mars Sample Return backward contamination – Strategic advice and requirements

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