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Modelling Panspermia in the TRAPPIST-1 System

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October 13, 2017

Modelling panspermia in the TRAPPIST-1 system

James A. Blake1,2*, David J. Armstrong1,2, Dimitri Veras1,2

Abstract

The recent ground-breaking discovery of seven temperate planets within the TRAPPIST-1 system has been hailed

as a milestone in the development of exoplanetary science. Centred on an ultra-cool dwarf star, the planets all orbit

within a sixth of the distance from Mercury to the Sun. This remarkably compact nature makes the system an ideal

testbed for the modelling of rapid lithopanspermia, the idea that micro-organisms can be distributed throughout the Universe via fragments of rock ejected during a meteoric impact event. We perform N-body simulations to

investigate the timescale and success-rate of lithopanspermia within TRAPPIST-1. In each simulation, test particles are ejected from one of the three planets thought to lie within the so-called ‘habitable zone’ of the star into a range of

allowed orbits, constrained by the ejection velocity and coplanarity of the case in question. The irradiance received

by the test particles is tracked throughout the simulation, allowing the overall radiant exposure to be calculated for

each one at the close of its journey. A simultaneous in-depth review of space microbiological literature has enabled

inferences to be made regarding the potential survivability of lithopanspermia in compact exoplanetary systems.

1Department of Physics, University of Warwick, Coventry, CV4 7AL 2Centre for Exoplanets and Habitability, University of Warwick, Coventry, CV4 7AL

*Corresponding author: [email protected]

Universe, and can propagate from one location to another. This

interpretation owes itself predominantly to the works of William

Thompson (Lord Kelvin) and Hermann von Helmholtz in the

latter half of the 19th Century. Indeed, Thompson provided an

excellent summation of the theory in 1871 [1]:

Contents

1

Introduction

1

1.1 Mechanisms for panspermia . . . . . . . . . . . . . . . 2

Radiopanspermia

•

Lithopanspermia

Pseudopanspermia • Other mechanisms

•

Directed panspermia

•

“We must regard it as probable in the highest degree that there are countless seed-bearing mete-

oric stones moving about through space. If at the

present instance no life existed upon this Earth, one such stone falling upon it might, by what we blindly call natural causes, lead to its becoming

covered with vegetation.”

1.2 Micro-organisms in low Earth orbit . . . . . . . . . . 3

Early missions

•

Spacelab

•

LDEF

•

EURECA

•

MIR-Perseus

•

Biopan • EXPOSE • Cosmic rays

1.3 Micro-organisms in simulation experiments . . . . 9

Planetary ejection • Atmospheric entry

1.4 The TRAPPIST-1 system . . . . . . . . . . . . . . . . . 13

Discovery • Habitability • Motivation

2

Theory

16

With these premises in place, panspermia has since been cham-

pioned by a number of prominent scientists, with notable con-

2.1 Equations of orbits . . . . . . . . . . . . . . . . . . . . . . 16

General orbits • Circular orbits

tributions from Svante Arrhenius [

2

  • ], Francis Crick [
  • 3], Fred

2.2 Impacting the target . . . . . . . . . . . . . . . . . . . . . 18

Hoyle [ ] and Chandra Wickramasinghe [

4

4,

5

,

6

]. Naturally,

this level of support for the theory has ensured that numerous

branches of thought have developed over the years, to be dis-

cussed further in Sec. 1.1. Panspermia would, however, remain

conjecture until the 1980s, a decade which welcomed the ability

to meticulously test the theory by exposing micro-organisms to

low Earth orbit environments. Such experiments, both pioneer-

ing and present-day, will receive attention in Sec. 1.2.

A particular surge of interest came in the 1990s as a result

of the Martian meteorite, ALH84001, which was found to pos-

sess structures that could indicate the presence of terrestrial nanobacteria. Careful testing of ALH84001, shown in Fig. 1,

has alluded to the presence of amino acids and polycyclic aro-

3

Simulation set-up

19

3.1 Simulation script . . . . . . . . . . . . . . . . . . . . . . . 19 3.2 Additional scripts . . . . . . . . . . . . . . . . . . . . . . . 20

4

Results and Discussion

21

4.1 Timescale and fate . . . . . . . . . . . . . . . . . . . . . . 21

4.2 Radiant exposure and survivability . . . . . . . . . . 22

4.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5

Further work

27 28 28

Acknowledgments References

matic hydrocarbons [7]. Whilst these can be an indication of

life, most experts agreed that the compounds most likely formed abiotically from organic molecules, or via contamination during

extraction. The past year has sparked a similar rise of interest

in panspermia, due to the discovery of seven Earth-sized plan-

ets in TRAPPIST-1, a system whose compact nature provides an unprecedented testbed for the process. This constitutes the

motivation for our study.

1. Introduction

The concept of panspermia (‘seeds everywhere’) has existed

since the ancient writings of the Greek philosopher Anaxagoras

(500 BC–428 BC), although his notion differs from that of the

current theory. In modern nomenclature, panspermia refers to

the hypothesis stating that seeds of life exist across the entire

Modelling panspermia in the TRAPPIST-1 system — 2/32

of lithopanspermia as a mechanism remains speculative, cer-

tain aspects have recently become testable experimentally [15].

An outline of these experiments is provided in Sec. 1.3. The

presence of Martian meteorites on Earth provides evidence of

the natural transfer of rock between planets within the Solar

System. This was anticipated in the mid–late 1800s by the likes

of Hermann von Helmholtz and Lord Kelvin, both of whom

favoured the lithopanspermia hypothesis [1, 16].

For lithopanspermia to take place, one would expect the

process to consist of three separate stages:

1. Planetary ejection – it was Cockell who first realised

that in order for life to be transported from one planet to

another, it must first be able to survive ejection from the

original planet [17]. Such an ejection would result from

the impacts of km–sized asteroids and comets, subjecting

the rock to extreme forces, accelerations and temperature increases. A combination of petrographic studies and numerical simulations of Martian rocks, ejected at

a velocity high enough to allow escape from Mars, have

unearthed shock pressure estimates of 5–55 GPa during

Figure 1. The ALH84001 Martian meteorite is

and has been found to contain organic carbon compounds.

∼

9 cm across

1.1 Mechanisms for panspermia

launch, alongside post-shock temperatures in the range

◦

  • 100–600 C [18
  • ,
  • 19]. Sec. 1.3 will provide further de-

Whilst we have so far referred solely to the general theory of

panspermia, numerous branches have developed over the last

couple of centuries, each proposing a separate mechanism for

the transfer of life throughout the Universe. Although there exists no conflict between the various mechanisms, and they could all be at work in relative harmony, it is important to

distinguish between them.

tails of these experiments, alongside others investigating

the effect of hypervelocity impact on the wellbeing of

micro-organisms. Whilst these impacts are undoubtedly

energetic in nature, a small proportion of the resulting ejecta will not exceed the lower limit of 100 ◦C. These

lower temperatures result from an ejection originating in

the ‘spall’ zone, referring to the targetted surface of the

impacted planet. Here, the shock wave from the impact

is effectively cancelled by the reflected shock wave from

the surface [20]. It has been estimated that more than a

billion fragments of rock have been ejected from Mars at such low temperatures throughout the history of the Solar System, with ∼5 % having the potential to land on Earth. What’s more, the Earth’s crust has been found to be inhab-

1.1.1 Radiopanspermia

Proposed originally by Arrhenius in his 1903 work, The Distri-

bution of Life in Space, radiopanspermia is the hypothesis that

micro-organisms can propagate through space, driven by stellar

radiation pressure alone [8]. His assertions were driven by the

knowledge that interplanetary space within our Solar System is

littered with micron-sized dust particles. Such particles, below

a critical size of 1.5 microns, would be driven away by the

radiation pressure of the sun, potentially transporting microbial

stowaways to other planetary systems.

  • ited by a number of micro-organisms [21 22]. To many,
  • ,

these findings have strongly supported the lithopansper-

mia hypothesis.

2. Transit in space – if the microbial life is able to survive

the ejection process, it must then withstand the inter-

planetary transfer that follows. The scale of this journey

will depend on the system in question, and whether the

lithopanspermia is occuring between planets of the same

system, or an entirely separate system. One specific case

that has been studied in great detail is exchange of ejecta

An intriguing theory, though one which quickly loses effectiveness as the size of the particle increases. In this sense, radiopanspermia as a mechanism for transporting life holds

solely for very small particles, at most hosting single bacterial

spores [9]. Furthermore, Shklovskij and Sagan asserted that it

is extremely unlikely that micro-organisms would be able to withstand the ‘lethal’ concoction of the solar UV and cosmic

radiation, whilst more recent studies have highlighted the dele-

  • between Mars and the Earth [
  • 9,
  • 14, 23]. Here, estimates

of journey times lie within the range of 1–20 million

years, although simulations appear to suggest that a small proportion of meteorites could reach Earth within the first

few years of travel [23]. This is the primary reason why

the seven recently discovered planets of the TRAPPIST-1

system (see Sec. 1.4) have generated such excitement within the fields of panspermia and astrobiology. The terious nature of the space vacuum [10 11, 12]. Experiments

looking into the effect of radiation on DNA stability have pro-

vided a final nail in the coffin for radiopanspermia, concluding

,that boulder-sized rocks ( provide effective shielding of bacterial spores from galactic cosmic radiation [13 14]. These findings instead support a

∼

1 m in diameter) are required to
,

mechanism involving much larger transportation vessels, such as asteroids and comets, known as lithopanspermia.

planets of this system all lie within a radius of

∼

5 % of

the Earth-Sun distance. As such, lithopanspermia within

the system is likely to occur on a much shorter timescale

when compared with the Earth-Mars case above. Simula-

tions performed by Krijt et al. (2017) found that ejecta released from planet f could reach the other ‘habitable’

1.1.2 Lithopanspermia

Lithopanspermia refers to the hypothesis that micro-organisms

shielded by rocks can travel from planet to planet through either interplanetary or interstellar space. Whilst the viability

Modelling panspermia in the TRAPPIST-1 system — 3/32

planet g within ∼80 years [24]. The present investigation

aims to extend these results, as detailed in Sec. 4. A number of experimental facilities have placed a focus

on assessing the response of microbial life to the testing

environments of outer space, making use of low Earth

nucleic acids stand alongside lipids, proteins and carbohydrates

to constitute the four main macromolecules necessary for life.

More recently, in 2012, scientists at Copenhagen University dis-

covered signatures of glycolaldehyde, a sugar which holds im-

portance in the production of RNA, around a solar-type young

star that resides in the binary system IRAS16293-2422 [33]. The following year, researchers found traces of cyanometha-

  • orbit satellites [
  • 9,
  • 15]. These will be outlined further in

Sec. 1.2.

3. Atmospheric entry – the final stage of lithopanspermia

to test involves hypervelocity entry from space through

the atmosphere of the target planet. As will be discussed

in Sec. 1.3, numerous experiments have subjected rock

samples containing micro-organisms to temperatures and pressures typically experienced by meteorites undergoing

atmospheric entry [15, 25].

nimine in a giant ISM gas cloud

∼

25000 ly from Earth. This

molecule is known to produce adenine, a nucleobase that con-

tributes to the ladder-like structure of DNA. The same project

also discovered the presence of ethanamine, thought to have a

part to play in the formation of alanine, one of twenty amino

acids found in the human genome [34]. Finally, in 2015, NASA announced that the compounds uracil, cytosine and thymine, all

key components of either DNA or RNA, had been successfully

produced within the laboratory, subject to conditions remanis-

cent of outer space [35].

1.1.3 Directed panspermia

In 1973, Crick and Orgel argued that life may have been pur-

posely spread throughout the Universe by an advanced extrater-

1.1.5 Other mechanisms

restrial civilisation [3]. Referred to as ‘directed panspermia’,
A variety of other hypotheses exist regarding possible mechanisms for panspermia. Belbruno and coworkers have shown

that low-energy transfer of rocks among protoplanets in orbit

around young stars should be fairly common, supporting the

theory of lithopanspermia [36]. Space probes are pushing new

frontiers, reaching further than ever before. This naturally raises

the question of whether such probes could cross-contaminate

throughout the Solar System and beyond. Whilst numerous

protection policies have been implemented, recent research has

found that certain microbes may still be immune to clean-room

procedures [37]. A rather alternative interpretation was pro-

posed by Dehel, who suggests that magnetic fields ejected from

the Earth’s magnetosphere could lift bacterial spores from the

atmosphere, and propel them towards other stellar systems [38].

Despite the wide range of theories that exist, the present work

will focus predominantly on the lithopanspermia hypothesis,

with particular emphasis on interplanetary transfer within the

same stellar system.

this theory asserts that life may have deliberately been sent to

seed the Earth. Naturally, this also concerns the seeding of other habitable worlds from the Earth, a feet that is fast becoming plausible due to developments in engineering (solar

sails), astronomy (exoplanets, astrometry) and biology (micro-

bial genetic engineering). Indeed, studies by astroecologists

have deduced that a number of key nutrients could be obtained

from materials typically found within asteroids [26].

In order to prove the hypothesis, it has been suggested that a distinctive ‘signature’ may be present in the genetic

code of early microbial life on Earth, reminiscent of the parent

civilisation [27]. Although evidence for such a signature is yet

to be found, the theory continues to raise interesting questions as modern advancements add to its plausibility.

1.1.4 Pseudopanspermia

Another form of panspermia, most notably championed by Chandra Wickramasinghe, is pseudopanspermia. According to this hypothesis, the solar nebula was able to draw in organic molecules that were already present in space during its formation. As the planets condensed from the nebula, these

molecules would have been incorporated and subsequently dis-

tributed among the planetary surfaces. It is thought that these

organic compounds then evolved to form life, via a process known as abiogenesis [28]. Wickramasinghe originally suggested formaldehyde, CH2O, as the main organic component

of interstellar dust, although many other ideas were raised [29].

Organic molecules in the interstellar medium are most com-

monly formed when an inorganic molecule becomes ionised,

usually due to interactions with cosmic rays [30]. Electrostatic

attraction then ensures that a reactant is drawn towards the

charged ion. Interstellar dust plays a key role by shielding the

newly formed organic molecules from UV light, which can

further ionise them [31].

1.2 Micro-organisms in low Earth orbit

The continued development of space flight has enabled numerous micro-organisms to be exposed directly to the harsh conditions of outer space. Prior to testing, such conditions

were thought to be extremely hostile to life. Most notably, the

vacuum of up to 10−14 Pa is an impenetrable barrier for the bio-

logical processes of growth, metabolism and reproduction [39].

What’s more, micro-organisms in space will undergo exposure

to a complex concoction of radiation. Whilst the solar UV

poses a particularly severe threat, bombardment by high energy

particles originating either from the star (e.g. stellar wind) or

from galactic/extragalactic space (cosmic rays) will also induce

adverse effects. A summary of the space environment measured for various low Earth orbit missions to be discussed in

this review is provided in Table 1.

To date, a number of intriguing discoveries have been made in support of pseudopanspermia. In 2008, radiometric dating of

Despite the hostile environment, certain life forms possess

the ability to survive long periods of time in a ‘dormant’ state,

organic species residing within the Murchison meteorite indi- such as bacterial and fungal spores. A spore is a resilient cas-

cated that the rock was non-terrestrial in origin, implying poten- ing which contains identical genetic information to the micro-

tial accretion from the interstellar medium (ISM) [32]. One of

the most notable molecules investigated was uracil, one of the

four nucleobases that make up the structure of ribonucleic acid

(RNA), the counterpart of deoxyribonucleic acid (DNA). The

organisms that are able to form it. The cores of bacterial spores

exhibit extremely low enzyme activity, thought to be due to their notable lack of water content. This contributes to their resilience, in conjunction with the fact that the spore DNA is

Modelling panspermia in the TRAPPIST-1 system — 4/32

Table 1. Space environment conditions measured for various low Earth orbit missions. Extended from Horneck et al. (2010) [9].

  • Space parameter
  • Spacelab
  • LDEF
  • EURECA MIR-Perseus
  • Biopan
  • EXPOSE

Vacuum pressure (Pa)

  • ∼ 10−4
  • ∼ 10−6
  • ∼ 10−5
  • ∼ 10−4
  • ∼ 10−6
  • ∼ 10−4

Irradiance (Wm−2 UV fluence (Jm−2
))

  • 1365
  • ∼1370
  • 1367
  • 1370
  • ∼1370
  • ∼ 1370

Undetermined

  • ≤ 103
  • ∼ 109

(>) 50, 170
4.8

  • ≤ 3×103
  • ∼ 107
  • ∼ 109

  • (>) 110, 170,
  • (>) 110, 170,
  • (>) 110, 170,

200, 290, 400

  • Spectral range (nm)
  • (>) 110
  • (>) 110

  • 290, 300
  • 280, 295

Cosmic ionising radiation dose (Gy)

  • 0.001
  • 0.2–0.4
  • 0.037–0.049
  • 0.004–0.074
  • 0.1–0.2

Temperature (K) Gravity (g)
243–290

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    Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 12 October 2020 doi:10.20944/preprints202010.0232.v1 Exploring Biogenic Dispersion Inside Star Clusters with System Dynamics Modeling Authors Javier D. Burgos. Corporación para la Investigacion e Innovación -CIINAS. Contact: [email protected] Diana C. Sierra. Corporación para la Investigacion e Innovación -CIINAS; Bogotá, Colombia. Contact: [email protected] Abstract The discovery of a growing number of exoplanets and even extrasolar systems supports the scientific consensus that it is possible to find other signs of life in the universe. The present work proposes for the first time, an explicit mechanism inspired by the dynamics of biological dispersion, widely used in ecology and epidemiology, to study the dispersion of biogenic units, interpreted as complex organic molecules, between rocky or water exoplanets (habitats) located inside star clusters. The 3 results of the dynamic simulation suggest that for clusters with populations lower than 4 M/ly it is not possible to obtain biogenic worlds after 5 Gyr. Above this population size, biogenic dispersion seems to follow a power law, the larger the density of worlds lesser will be the impact rate (훽.) value to obtain at least one viable biogenic Carrier habitat after 5 Gyr. Finally, when we investigate scenarios by varying β, a well-defined set of density intervals can be defined in accordance to its characteristic β value, suggesting that biogenic dispersion has a behavior of “minimal infective dose” of “minimal biogenic effective” events by interval i.e. once this dose has been achieved, doesn’t matter if additional biogenic impact events occur on the habitat.
  • Advances in Understanding of Desiccation Tolerance of Lichens and Lichen-Forming Algae

    Advances in Understanding of Desiccation Tolerance of Lichens and Lichen-Forming Algae

    plants Review Advances in Understanding of Desiccation Tolerance of Lichens and Lichen-Forming Algae Francisco Gasulla *, Eva M del Campo, Leonardo M. Casano and Alfredo Guéra * Department of Life Sciences, Universidad de Alcalá, Alcalá de Henares, 28802 Madrid, Spain; [email protected] (E.M.d.C.); [email protected] (L.M.C.) * Correspondence: [email protected] (F.G.); [email protected] (A.G.) Abstract: Lichens are symbiotic associations (holobionts) established between fungi (mycobionts) and certain groups of cyanobacteria or unicellular green algae (photobionts). This symbiotic association has been essential in the colonization of terrestrial dry habitats. Lichens possess key mechanisms involved in desiccation tolerance (DT) that are constitutively present such as high amounts of polyols, LEA proteins, HSPs, a powerful antioxidant system, thylakoidal oligogalactolipids, etc. This strategy allows them to be always ready to survive drastic changes in their water content. However, several studies indicate that at least some protective mechanisms require a minimal time to be induced, such as the induction of the antioxidant system, the activation of non-photochemical quenching including the de-epoxidation of violaxanthin to zeaxanthin, lipid membrane remodeling, changes in the proportions of polyols, ultrastructural changes, marked polysaccharide remodeling of the cell wall, etc. Although DT in lichens is achieved mainly through constitutive mechanisms, the induction of protection mechanisms might allow them to face desiccation stress in a better condition. The proportion and relevance of constitutive and inducible DT mechanisms seem to be related to the ecology at which lichens are adapted to. Citation: Gasulla, F.; del Campo, E.M; Casano, L.M.; Guéra, A.
  • Evolutionary Processes Transpiring in the Stages of Lithopanspermia Ian Von Hegner

    Evolutionary Processes Transpiring in the Stages of Lithopanspermia Ian Von Hegner

    Evolutionary processes transpiring in the stages of lithopanspermia Ian von Hegner To cite this version: Ian von Hegner. Evolutionary processes transpiring in the stages of lithopanspermia. 2020. hal- 02548882v2 HAL Id: hal-02548882 https://hal.archives-ouvertes.fr/hal-02548882v2 Preprint submitted on 5 Aug 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. HAL archives-ouvertes.fr | CCSD, April 2020. Evolutionary processes transpiring in the stages of lithopanspermia Ian von Hegner Aarhus University Abstract Lithopanspermia is a theory proposing a natural exchange of organisms between solar system bodies as a result of asteroidal or cometary impactors. Research has examined not only the physics of the stages themselves but also the survival probabilities for life in each stage. However, although life is the primary factor of interest in lithopanspermia, this life is mainly treated as a passive cargo. Life, however, does not merely passively receive an onslaught of stress from surroundings; instead, it reacts. Thus, planetary ejection, interplanetary transport, and planetary entry are only the first three factors in the equation. The other factors are the quality, quantity, and evolutionary strategy of the transported organisms.
  • March 21–25, 2016

    March 21–25, 2016

    FORTY-SEVENTH LUNAR AND PLANETARY SCIENCE CONFERENCE PROGRAM OF TECHNICAL SESSIONS MARCH 21–25, 2016 The Woodlands Waterway Marriott Hotel and Convention Center The Woodlands, Texas INSTITUTIONAL SUPPORT Universities Space Research Association Lunar and Planetary Institute National Aeronautics and Space Administration CONFERENCE CO-CHAIRS Stephen Mackwell, Lunar and Planetary Institute Eileen Stansbery, NASA Johnson Space Center PROGRAM COMMITTEE CHAIRS David Draper, NASA Johnson Space Center Walter Kiefer, Lunar and Planetary Institute PROGRAM COMMITTEE P. Doug Archer, NASA Johnson Space Center Nicolas LeCorvec, Lunar and Planetary Institute Katherine Bermingham, University of Maryland Yo Matsubara, Smithsonian Institute Janice Bishop, SETI and NASA Ames Research Center Francis McCubbin, NASA Johnson Space Center Jeremy Boyce, University of California, Los Angeles Andrew Needham, Carnegie Institution of Washington Lisa Danielson, NASA Johnson Space Center Lan-Anh Nguyen, NASA Johnson Space Center Deepak Dhingra, University of Idaho Paul Niles, NASA Johnson Space Center Stephen Elardo, Carnegie Institution of Washington Dorothy Oehler, NASA Johnson Space Center Marc Fries, NASA Johnson Space Center D. Alex Patthoff, Jet Propulsion Laboratory Cyrena Goodrich, Lunar and Planetary Institute Elizabeth Rampe, Aerodyne Industries, Jacobs JETS at John Gruener, NASA Johnson Space Center NASA Johnson Space Center Justin Hagerty, U.S. Geological Survey Carol Raymond, Jet Propulsion Laboratory Lindsay Hays, Jet Propulsion Laboratory Paul Schenk,
  • Space and Planetary Informatics Laboratory

    Space and Planetary Informatics Laboratory

    Division of Information and Systems Space and Planetary Informatics Laboratory Hirohide Demura Yoshiko Ogawa Kohei Kitazato Chikatoshi Honda Senior Associate Pro- fessor Associate Professor Associate Professor Associate Professor Space and Planetary Informatics Laboratory Our laboratory is newly established in April 2015. Lab members are a part of CAIST/ARC-Space, Profs. Demura, Ogawa, Honda, and Kitazato. We have served concurrently as this lab and CAIST/ARC-Space cluster. We contribute to deep space exploration for insighting the origin and evolution of our Solar System, and for expanding activities of human beings to space, ac- cording to the philosophy of the university `to Advance Knowledge for Humanity'. Aim to serve as a hub institute which provides software for geoinformatics, geographic information system (GIS) and remote sensing used for frontier projects in the field of space development of Japan, by utilization of our University's in- novativeness in information science. This cluster contributes to space develop- ment/exploration programs in cooperation with other agencies/universities, on the basis of the MOU between JAXA and UoA `Promotion of Solar System Science by means of archived data'. Additional activity is researches/developments for monitoring Azuma volcanoes in Fukushima by means of SAR (Synthetic Aperture Radar) analysis with Earth Observation Satellite as members of the satellite anal- ysis group of the Meteorological Agency Eruption Predictive Liaison Committee. Joining Projects 1. Hayabusa2 to the asteroid 162173 Ryugu 2. TANPOPO on International Space Station 3. MMX (Martian Moons eXploration) 4. JUICE (JUpiter ICy moons Explorer) 239 Division of Information and Systems 5. The next lunar lander mission (SLIM) 6.
  • 18Th EANA Conference European Astrobiology Network Association

    18Th EANA Conference European Astrobiology Network Association

    18th EANA Conference European Astrobiology Network Association Abstract book 24-28 September 2018 Freie Universität Berlin, Germany Sponsors: Detectability of biosignatures in martian sedimentary systems A. H. Stevens1, A. McDonald2, and C. S. Cockell1 (1) UK Centre for Astrobiology, University of Edinburgh, UK ([email protected]) (2) Bioimaging Facility, School of Engineering, University of Edinburgh, UK Presentation: Tuesday 12:45-13:00 Session: Traces of life, biosignatures, life detection Abstract: Some of the most promising potential sampling sites for astrobiology are the numerous sedimentary areas on Mars such as those explored by MSL. As sedimentary systems have a high relative likelihood to have been habitable in the past and are known on Earth to preserve biosignatures well, the remains of martian sedimentary systems are an attractive target for exploration, for example by sample return caching rovers [1]. To learn how best to look for evidence of life in these environments, we must carefully understand their context. While recent measurements have raised the upper limit for organic carbon measured in martian sediments [2], our exploration to date shows no evidence for a terrestrial-like biosphere on Mars. We used an analogue of a martian mudstone (Y-Mars[3]) to investigate how best to look for biosignatures in martian sedimentary environments. The mudstone was inoculated with a relevant microbial community and cultured over several months under martian conditions to select for the most Mars-relevant microbes. We sequenced the microbial community over a number of transfers to try and understand what types microbes might be expected to exist in these environments and assess whether they might leave behind any specific biosignatures.