Planetary Protection Microbial Tourism and Return to Earth

Planetary Protection: Microbial Tourism and Return to Earth John D. Rummel SETI Institute/Friday Harbor Partners LLC <rummelj@ecu. edu> 26 March 2020

Planetary Protection is Integral to Answering Astrobiology’s “Big Questions” • How does life begin and evolve? • Does life exist elsewhere in the Universe? • What is the future of life on Earth and beyond? – To the extent that those answers can be found within our own solar system, even (perhaps) on Mars 2

A Solar System with ~ 10 Ocean Worlds Earth (Hi Mom!) Enceladus Mars Ceres Titan Europa Callisto 26 March 2020 Ganymede Dione Mimas (? ) 3

• Earth organisms live in extreme environments previously thought of as impossible: – – – – – Reproducing at ≥ 121°C; and at temperatures down to -18°C Where water activity is 0. 6 and higher; even when delivered only as vapor Ecosystems featuring chemosynthetic, symbiotic, and mineral-organogenic processes Volcanic/geothermal vents in boiling water at the Earth’s surface Deep-sea hydrothermal vents (liquid water @ >250 ATM) Deep subsurface in terrestrial (>3 km) and marine (>1 km below seafloor) systems; Pressures from 0 to 1680 MPa In mine seepage acids, with p. H of -0. 6 (yes, minus!) to serpentinization sites w/ p. H > 11 High-radiation environments (some survive ≥ 5 Mrad [≥ 6000 Gy]) In rocks in hot deserts; Antarctic dry-valley sandstones; using mineralogy as a shield During long-term space exposure (LDEF, EURECA, EXPOSE, O/OREOS, etc. ) 4

Where are the best places to search for life in our solar system? Earth Mars Europa Enceladus

Biological Invasions are No Joke (1) 1. In 1859, an English farmer by the name of Thomas Austin introduced just 24 grey rabbits to his plot of land in Australia to remind him of home – They caused serious erosion of soils across the continent by overgrazing and burrowing, and are believed to be the most significant known factor for species loss in Australia's history – By 1900, the Australians were killing 2 million rabbits a year, without lowering the population – They are currently controlled by an introduced virus (rabbit haemorrhagic disease virus [RHDV] or myxomatosis) 26 March 2020 6

Biological Invasions are No Joke (2) 2. The Kudzu vine was first brought to the United States in 1876 when it was featured at the Philadelphia Centennial Exposition as a hardy, fast-growing vine that could help inhibit soil erosion – – It is also known as the "mile-a-minute vine" or "the vine that ate the South” Kudzu has been spreading across the U. S. at a rate as fast as 150, 000 acres annually, due primarily to the fact that its individual vines can grow upwards of a foot per day 26 March 2020 7

Biological Invasions are No Joke (3) 3. The chestnut blight was accidentally introduced to North America around 1904 when Cryphonectria parasitica was introduced into the United States from Japanese chestnut nursery stock – The fungus is spread by wind-borne ascospores affecting the American chestnut tree – In the first half of the 20 th Century it killed an estimated 4 billion trees, having a devastating economic and social impact on communities in the eastern United States – In the Appalachian Mountains, one in every four hardwoods had been an American chestnut 26 March 2020 8

Contaminated Field Sites Aren’t Either! • Taking a $2 B rover to Mars and studying the organics and microbes you brought with you is not cost-effective • If you want to study life in Florida, it is far less expensive to stay in Florida (or Kazakhstan, or California, or wherever) • Molecular methods capable of identifying ALL Earth organisms are not yet in regular use by spaceflight engineers. . • • We cannot definitively rule out any terrestrial microbial taxon from being included in the potential “passengers” on a spacecraft to the outer planets Notwithstanding extensive spacecraft biodiversity studies, it is necessary to consider adaptations made by all Earth organisms, and not just those that appear on a currently identified subset or “passenger list” 26 March 2020 9

COSPAR Planetary Protection Policy: Protect Science, Protect the Earth • “The conduct of scientific investigations of possible extraterrestrial life forms, precursors, and remnants must not be jeopardized” Avoid forward contamination; don’t “discover” life we brought with us • “The Earth must be protected from the potential hazard posed by extraterrestrial matter carried by a spacecraft returning from an interplanetary mission” Avoid backward contamination; don’t contaminate the Earth • “For certain space-mission/target-planet combinations, controls on organic and biological contamination carried by spacecraft shall be imposed” Tailor requirements by target location and mission type 26 March 2020 10

Listen to the Outer Space Treaty: Or to Bart: “States Parties to the Treaty shall pursue studies of outer 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 resulting from the introduction of extraterrestrial matter” 26 March 2020 11

International Agreements on Planetary Protection The United Nations Outer Space Treaty (OST) of 1967: • • • Proposed to the UN in 1966 Signed by the US, UK and Soviet Union in January 1967 Ratified by the US Senate on April 25 th, 1967 OST Article IX: “. . . parties to the Treaty shall pursue studies of outer 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 resulting from the introduction of extraterrestrial matter and, where necessary, shall adopt appropriate measures for this purpose. . . ” COSPAR maintains an international consensus planetary protection policy under the Treaty 12

Viking Missions to Mars, 1975 (Landed 1976) • These two missions were the first successful landings on another planet • They attempted to grow martian organisms in Earthlike conditions, but did not find chemical compounds usually associated with life • It may be that their search for those compounds was flawed. . 14

Viking and Planetary Protection • Two key things happened together—protecting Mars from viable Earth organisms, and ensuring low biosignature contamination in life detection instruments • Once accepted the requirements had the full support of management and a commensurate level of investment in spacecraft design and testing – Particularly the landers, which had to undergo full-system sterilization – Future missions to Europa and Enceladus, as well as Mars, will need to make a similar level of design and test effort to achieve science goals 15

Viking Life-Detection Package

Deep-Sea Hydrothermal Vents on Earth (1977) – Life-as-we-didn’t know it Vents Glow: 350 C+ Planetary protection provisions are important, not because we expect to find these things out there, but because we didn’t expect to find them here! 17

Post-Viking Requirements for Robotic Lander Missions to Mars (SSB) Have been based on the requirements implemented by the Viking lander missions: • Lander systems not carrying instruments for the investigations of extant martian life or entering special regions are to be as clean as the Vikings were before they went into the oven • Lander systems searching for life, or planning to enter special regions, must be as clean as the Vikings were after they came out of the oven 18

Viking’s Planetary Protection Legacy • The Viking Project worked to ensure that “investigations of life forms, precursors, and remnants” were not compromised, but did not unequivocally detect life – The Exo. Mars rover mission is the next attempt to clean hardware to Viking levels – Similar levels of contamination control are a challenge for Mars 2020 “Perseverance” 19

Mars Special Regions A Special Region is defined as a region within which terrestrial organisms are likely to replicate. Any region which is interpreted to have a high potential for the existence of extant martian life forms is also defined as a Special Region. Given current understanding of terrestrial organisms, Special Regions are defined as areas or volumes within which sufficient water activity AND sufficiently warm temperatures to permit replication of Earth organisms may exist. The physical parameters delineating applicable water activity and temperature thresholds are given below: • Lower limit for water activity: 0. 5; Upper limit: 1. 0 • Lower limit for temperature: -25�C; No Upper limit • Timescale within which limits can be identified: 500 years *Rummel, J. D. , Beaty, D. W. , Jones, M. A. , Bakermans, C. , Barlow, N. G. , Boston, P. J. , . . . & Wray, J. J. A New Analysis of Mars “Special Regions”: Findings of the Second MEPAG Special Regions Science Analysis Group (SR-SAG 2). Astrobiology, 14, 887 -968, 2014.

Preliminary Map of Features of Relevance to Interpreting Special Regions – and Future Human Settlements on Mars SR-SAG 2 May 1, 2014 Background colors represent topography from MOLA.

Back Contamination Requirements Samples from Mars, etc. An Earth return mission from Mars is classified, “Restricted Earth return” • The outbound mission shall meet the contamination control requirements for life-detection missions, unless specifically exempted – This provision should avoid “false positive” indications in a life-detection and hazard -determination protocol – A “false positive” could prevent distribution of the sample from containment and could lead to unnecessary increased rigor in the requirements for all later missions – The inability to complete the biohazard protocol due to too many false positives could lead to a “false negative” that could endanger the Earth’s biosphere 26 March 2020 22

Back Contamination Requirements Samples from Mars, etc. • The mission must provide a method to “break the chain of contact” with the target body • No uncontained hardware that contacts target material shall be returned to the Earth’s biosphere or the Moon – Isolation of such hardware shall be provided during sample container loading into the containment system, launch, and any inflight transfer operations required • For unsterilized samples returned to Earth, a program of life detection and biohazard testing, or a proven sterilization process, shall be undertaken as an absolute precondition for controlled distribution of any portion of the sample 26 March 2020 23

Designing for Planetary Protection Like designing for radiation exposure—consider it early and often: • Consider parts qualifications and manufacturing processes when selecting components • Parts not qualified above 70°C may withstand higher temperatures if treated while inactive: use a test program and approved parts list • Start clean and keep things clean; good cleanroom practices minimize recontamination • Dry heat is generally the most benign method of decontamination, but there a number of others that can be used alone or in combination (e. g. , plasma, gamma, VHP) 26 March 2020 24

Designing for Planetary Protection (II) Signs of life may be very small – viruses may not be alive, but they are indicators of living cells – or they may be much larger, like this tardigrade: still too small to see, but capable of living in environments we would consider to be “extreme. ” Eliminating living organisms from spacecraft, or at least identifying those that are passengers – while not killing the spacecraft – is one of the tasks of an effective planetary protection program. 26 March 2020 25

Future Flights to Mars with Humans “What we learn about the Red Planet will tell us more about our Earth’s past and future, and may help answer whether life exists beyond our home planet. Together with our partners, we will pioneer Mars and answer some of humanity’s fundamental questions: • Was Mars home to microbial life? Is it today? • Could it be a safe home for humans one day? • What can it teach us about life elsewhere in the cosmos or how life began on Earth? • What can it teach us about Earth’s past, present, and future? ”

Humans on Mars 26 March 2020 27

Can we get these people as interested in Mars as they are in shirt-sleeve tourism on Earth?

Maybe – but it is going to be a real challenge! On the other hand, the wheel-chair set will love it….

We Live in a Sea of Living Organisms • Humans have commensal microorganisms on which they rely— Approximately 50% of the cells in the human body are non-human microbes, and most of them are currently unidentified except by genetic sequence • There approximately 10 trillion human commensals carried in and on each of our bodies • Adding humans (as autonomous microbial growth and distribution systems) into a search for unknown microbial life is a major complication — one that could put an answer to the question of “life on Mars” out of reach for an extended and potentially unlimited period of time

Alas, we have a long way to go…. Impact of Biofilms on the Design and Operations of ISS Life Support Systems Layne Carter, ISS Water Subsystem Manager, NASA MSFC Chris Brown, Flight Operations Directorate, NASA JSC/Leidos From the American Society for Gravitational and Space Research, 2017 meeting online: For a truly film-worthy point of view, I highly recommend you watch this presentation: <https: //ac. arc. nasa. gov/pu 38 nzxvwu 0 u/? launcher=false&fcs. Content=true&pb. Mode=normal> at 19: 00

A very long way to go… … space stations (and cruise ships) can harbor some pretty nasty microbes, etc.

COSPAR Human Exploration Principles “The intent of this planetary protection policy is the same whether a mission to Mars is conducted robotically or with human explorers. Accordingly, planetary protection goals should not be relaxed to accommodate a human mission to Mars. Rather, they become even more directly relevant to such missions—even if specific implementation requirements must differ” • Safeguarding the Earth from potential back contamination is the highest planetary protection priority in Mars exploration • The greater capability of human explorers can contribute to the astrobiological exploration of Mars only if human-associated contamination is controlled and understood • For a landed mission conducting surface operations, it will not be possible for all human associated processes and mission operations to be conducted within entirely closed systems • Crewmembers exploring Mars, or their support systems, will inevitably be exposed to martian materials *Developed following joint ESA-NASA Workshop; Kminek, G. , Rummel, J. , & Race, M. (2007). Planetary Protections and Human System Research & Technology. In ESANASA Workshop Report, ESA WPP-276, ESTEC, Noordwijk, The Netherlands.

One Human Exploration Concept 1 Human Habitation Human Traverse 1, 2 a “Safe Zone” from precursors (may be entire surface) Lab Hab 2 a Safe Zone for Human Activities Robotic/Teleoperation Human Traverse 3 Unexplored Hypothetical Special Region/Potential SR Robotic Traverse “Clean” Rover Transfer Site 2 b, 3 “Life Sites” defined from remote sensing data 2 b Hypothetical Special Region with Robotic Exploration 34

It’s all about dust – and maybe about mud, too!

Biosignatures at many scales may need humans to find them Red Tulip Microbial Iron Stalagmites, Zoloushka Cave, Ukraine Poofball Sea, Thrush Cave, SE Alaska Manganese Microbe Stalagmite on Miner’s Jacket, Soudan Mine, MN The Hunt for Blue Goo Copper Subsurface Organisms SEMs by M. Spilde & P. Boston Lavatube Microbes on Ferrous Crystals, Courtesy of D. Northup & M. Spilde Boston, P. J. et al 2001. Cave biosignature suites: Microbes, minerals and Mars. Astrobiology 1(1): 25 -55.

And caves on Mars are unknown, but promising -3 o. C, SO 2 , CO 2, CO & other gases Sulfuric acid (p. H=0), H 2 S, CO, & other reduced gases Cueva de Villa Luz, Tabasco, Mexico. Image courtesy of National Geographic Society Fumarolic Caves in ice, Mt. Rainier, WA. Image courtesy of E. Cartaya World’s largest cave speleothem, 18. 5 km & going Mn oxidation, localized CH 4 sources, etc. 40 -60 o. C, 100% Rh Naica Caves, Chihuahua, Mexico Snowy River, Ft. Stanton Cave, NM, Image, BLM, Courtesy of J. Gant

Yes, those are people in there! Naica Caves, Chihuahua, Mexico 40 -60 o. C, 100% Rh

Can Mars Be a Home for Humanity? • Earth organisms could pose a potential risk to the use of local resources if they are allowed to spread unchecked – For example Earth microbes introduced into a subsurface aquifer on Mars could mineralize dissolved elements in the water and greatly reduce or eliminate the permeability of that aquifer 39

The Future of Mars? – Historical Perspective “The relationship between planetary strategy and quarantine standards is a dynamic one. Both are affected by completed explorations, future technology, and changes in the goals of the exploration. The future utility of the planet Mars, other than for scientific investigation, has not been carefully analyzed but it has an important bearing on both these issues. We might, at some time in the future, want to attempt to revise the atmosphere of Mars to make it more habitable. A likely component of such an engineering scheme would be specially contrived plant forms which might be at a great disadvantage in competition with accidental terrestrial contaminants. For such a scheme, contaminants could be a hazard even if they merely persisted on Mars without extensive proliferation prior to attempts to reengineer the planet. ” – E. Levinthal and J. Lederberg, LSSR (1968) 40

My Opinion • If you don’t take steps to limit human-associated contamination, the reasons to go and explore Mars evaporate, like the frost on Utopia Planitia on a summer afternoon • Both science and colonization are at risk

Humans on Mars – Conclusions • Serious consideration must be given to limiting contamination that would corrupt or destroy evidence of extraterrestrial life • In view of recent discoveries about Earth extremophiles and Mars environments, there are places on Mars, today, that could be contaminated by Earth organisms • Qualitative and quantitative requirements applicable to human spaceflight need to be developed to support the design and development of human missions to Mars • COSPAR, NASA, ESA, and other space agencies have developed principles and guidelines applicable to human Mars missions, and are working together to develop human mission requirements 42

Plant-based life support systems are essential for long duration stays off of the Earth – Plants, as life support processors, have been tuned over 2 or more billion years of evolution, but: – One has to remember that plants have an “on” switch, and an “off” switch, but once you use the “off” switch the “on” switch may no longer work….

Please keep your plant pathogens away from Mars!

Something else to consider!

Planetary Protection Fulfills a Dual Purpose: ü Ensure that science is not compromised ü Safeguard Earth’s biosphere from harmful contamination carried in returned samples Embodied in the UN Outer Space Treaty of 1967 Consensus Policies Developed by COSPAR since 1958 26 March 2020 Planetary Protection Measures for Robotic & Human Missions – Updates based on Changes in Science – Avoid: ü Forward Contamination ü Backward Contamination 47

The Truth is (Still) Out There! Let’s not destroy the opportunity to learn it…. 48

Questions?

Astrobiology Strategy (2015) “What role does planetary protection play in astrobiology? • How do we mitigate the bias in our search for life on other worlds that would be introduced if we – either accidentally or through human exploration – brought Earth-based life with us to other planets? • If astrobiological research requires samples to be returned to Earth from potentially habitable environments, how do we protect Earth life from competition or invasion from alien organisms? ” 50

Designing for Planetary Protection • Nothing beats a spacecraft in a casserole dish, and the right recipe! But some spacecraft designs take new work to ensure they can meet requirements 26 March 2020 51