Planetary Protection in Future Solar System Exploration E S P I PERSPECTIVES 64 Planetary Protection in Future Solar System Exploration Arne LAHCEN Project Manager at the European Space Policy Institute This Perspective analyses the importance of planetary protection in the future exploration of the Solar System. A major obstacle in this respect seems to be the contested scope of planetary protection. Although the more specific issue of planetary contamination has been addressed by the United Nations and various national space agencies, none of them have developed a holistic and all-embracing concept of planetary protection. As a consequence, the increasing number of planetary exploration probes, the prospect of a sample return mission - and maybe even manned missions to Mars in the long run - might have side-effects that limit future options, resulting in catastrophic events, or putting humankind in a position that might be regretted in the future, given the changing relationship between the environment and ourselves. Although the exploration of Mars is most relevant in this respect, the issues addressed in this Perspective might be relevant in establishing a sustainable relationship with the Solar System as a whole. 1. Introduction returned from other solar system bodies”1. This definition clearly exposes the two major Literally, planetary protection (PP) could be motivations for planetary protection. understood as the combination of all practices and actions that help protect one or more celestial The first one aims at protecting science as the bodies. In this wide interpretation, space utilisation unbiased implementation of exobiological has been an enabling asset in protecting the Earth experiments must be ensured in order to avoid and its inhabitants. Satellites have given us the false conclusions. In the context of forward opportunity to gather a diverse set of information, contamination this could lead to false positives which in turn helps us address issues of land use, (e.g. the discovery of traces of life on an climate change, atmospheric and oceanic extraterrestrial (ET) sample, while it is not monitoring, etc. indigenous), whereas false negatives are more likely to occur in the event of a planet-wide Most of the time, however, that is not the contamination by terrestrial life that would destroy presumed substance of the concept ‘planetary existing extraterrestrial life. protection’. Initially, the concept was postulated to prevent, or at least minimise, the impacts that can The second argument relates to safety. Often arise in the interplanetary exploration of celestial administered in the context of backward bodies by means of probes, robots or human contamination, it states Earth’s biosphere and the exploration. A major matter of concern in this Moon must be protected against possible respect is planetary contamination. According to contamination by extraterrestrial forms of life, which could be embedded in return samples or NASA, planetary protection is the term given to 2 “the practice of protecting solar system bodies carried by return probes or crews. For backward such as planets, moons, comets, and asteroids from contamination by Earth life, and protecting 1 Earth from possible life forms that may be Conley, C., Planetary Protection: About Planetary Protection, NASA, 2010, http://planetaryprotection.nasa.gov/about/. 2 Goh, G.M. and Kazeminejad, B., “Mars Through the Looking Glass: an Interdisciplinary Analysis of Forward and Backward Contamination” Space Policy 20 (2004): 217–225. ESPI Perspectives No. 64, December 2012 1 Planetary Protection in Future Solar System Exploration contamination, the potential effects that are of matter and, where necessary, shall adopt concern about biohazards can be divided into appropriate measures for this purpose.”4 three broad categories: (1) large-scale negative pathogenic effects in humans; (2) destructive COSPAR, responsible for the compliance with the impacts on Earth’s ecological systems or PP provisions of the OST, has elaborated working environments; and (3) toxic and other effects methods for determining the bioburden5 threshold attributable to microbes, their cellular structures, on spacecraft and their components. As a result of or extracellular products.3 new knowledge about the habitability of other celestial bodies and the capability of terrestrial Various measures in terms of legislation and microorganisms to survive in extreme engineering have been developed to ensure a environments, COSPAR’s methodology has proper implementation and execution of planetary changed over time. Between 1964 and the mid- contamination practices. 1980s, a probabilistic approach was followed. It implied that space faring nationals had to conduct 2. The Focus on Planetary Contamination their unmanned exploration in such a way that the total probability of contamination during a –3 The idea of planetary protection already emerged specified quarantine period did not exceed 10 . In during the formation of the space program in the 1984, this quantitative policy was replaced by an United States. The International Astronautical entirely new and categorical approach, in which Federation (IAF) first took a look at the problem in the requirements for bioburden reduction were 1956, a year before Sputnik. Later, during the dependant upon the target body and the type of 1960s, the International Council of Scientific mission. Unions established the Committee on Space Research (COSPAR). Despite its position as a To this effect, expertise and various practices consultative body of the United Nations only, this have been developed in-house by the different multidisciplinary committee has been able to space agencies engaged in solar system determine the standards upon which national exploration programmes. The bioburden practices has been based for over the past 40 assessment throughout spacecraft assembly, test years. and launch operations is based upon cleanroom cleanliness. Active bioburden reduction is mainly At the same time, the UN had created the achieved by dry-heat sterilisation and physical Committee on the Peaceful Uses of Outer Space cleaning methods by means of alcohol swaps. (UNCOPUOS). This committee has played a vital The latest developments include alternative role in the development of space law as a sterilisation methods such as gas plasma respected field of international law, and has treatment and UV irradiation. eventually led to a first legal basis for planetary protection. The first reference to the concept was Note that abovementioned legislation and included in the “Declaration of Legal Principles practices are only concerned with the issue of Governing the Activities of States in the planetary contamination. A genuine planetary Exploration and Use of Outer Space”. This UN protection conceptualisation, however, is wider resolution, however, did not contain any specific and requires a holistic, overarching perspective. mention of biological contamination. COSPAR in the meantime adopted resolution 26, which 3. Towards an Integrated PP Approach? provided the first international standards for planetary quarantine. One could, for example, argue that we need to extend the interpretation of planetary protection The crowning achievement in terms of planetary beyond the instrumental protection of scientific protection legislation was the “Treaty on Principles resources as expressed in the planetary Governing the Activities of States in the contamination policy.6 In this view, the objective of Exploration and Use of Outer Space, including the planetary protection is much wider than merely Moon and Other Celestial Bodies”, also referred to avoiding planetary contamination. From a more as the “Outer Space Treaty” (OST). Adopted by distant perspective, this discussion on planetary the UNCOPUOS in 1963, article IX of the OST protection fits in a wider tradition of environmental defines that states “shall pursue studies of outer ethics. Different motivations in support of this space, including the moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth 4 United Nations, 1966: Res. No. 2222, art. IX 5 resulting from the introduction of extraterrestrial Bioburden is the level of microbial contaminion, measured as the total number of microbes or by considering the microbial density. 3 U.S. National Research Council, Assessment of Planetary 6 Cockell, S.C. et al., “Effects of a Simulated Martian UV Flux Protection Requirements for Mars Sample Return Missions, on the Cyanobacterium, Chroococcidiopsis sp. 029.” Washington D.C.: The National Academies Press, 2009. Astrobiology 5.2 (2005): 127–140. ESPI Perspectives No. 64, December 2012 2 Planetary Protection in Future Solar System Exploration notion have been developed; basically they can reasonable objective measurement of value. This be grouped into four categories of arguments:7 might also be helpful in dealing with value based questions involving issues such as interaction with 1. The necessity argument implies that we need unaltered indigenous primitive extraterrestrial life forms.9 wilderness areas to create a complete and healthy concept of ‘culture’ and ‘civilisation’. Without them, we are more philosophically barbaric. Some scholars argue that 4. Future Challenges in some way wilderness areas, such as the concept of ‘planetary reserves’ represent ‘intelligence’, since the label wilderness is a product of an animal that