Projects: LIFE Experiment: Phobos
Frequently Asked Questions
General FAQ
Experiment Size and Design
Planetary Protection
General FAQ:
Why are we trying to fly microorganisms to Phobos and back?
To test whether organisms can survive for years in deep space. We want to fly selected organisms in a simulated meteoroid -- a small canister on board the Russian Phobos-Soil sample return -- over a three-year mission. LIFE (Living Interplanetary Flight Experiment) will test one aspect of transpermia, the hypothesis that life could survive space travel, if protected inside rocks blasted by impact off one planet to land on another. For example, could they make it from Mars to Earth? Organisms have never been tested to see if they could survive beyond the protection of Earth’s magnetosphere for multi-year periods.
What is the status of this experiment?
This experiment is being done in collaboration with the Space Research Institute and the Institute of Microbiology of the Russian Academy of Sciences. Currently, the experiment is under formal consideration by NPO Lavochkin, the engineering organization building the spacecraft, for inclusion on the Russian Phobos-Soil sample return mission. The Planetary Society team is designing the experiment and studying the planetary protection issues. NPO Lavochkin is studying accommodation and will make the final decision as to accommodation of the experiment on the mission. Note that all of the information presented here is preliminary and subject to change. We are also on the lookout for other opportunities to fly on other deep-space return missions.
Why the Phobos Sample Return mission?
Currently, the Phobos-Soil sample return mission is the only scheduled mission that will return to Earth from deep space, far beyond the protection of Earth’s magnetic field (see next question for more). It offers a rare opportunity for a return trip to interplanetary space for approximately 34 months. We are hoping to fly a similar experiment on other missions.
Couldn’t you just do this on an Earth orbiting spacecraft?
Earth’s magnetosphere, the area of influence of its magnetic field, protects near-Earth spacecraft (and any life that would be flying upon them) from the charged particle component of galactic cosmic radiation (GCR) and solar particle events (SPE). Sending biological samples through deep space is therefore a much better test of interplanetary survivability than sending the samples on a typical Earth-orbiting flight.
Has this type of experiment ever been done before?
Not with the combination of multi-year time periods and exposure beyond the protection of Earth’s magnetosphere. In this regard, European experiments called Biostak 1 aboard Apollo 16 and Biostak 2 on Apollo 17 carried biological samples outside the magnetosphere, but only for periods of many days. Since then, various European, Russian, and American biological survival experiments have flown in low-Earth orbit: Biostak 3, Biobloc, Advanced Biostak, the Long Duration Exposure Facility (LDEF), Biopan, Experiment Exobiologie, and the Planetary Society’s Growth of Bacteria on Surfaces in Space (GOBSS). With the exception of GOBSS, which was recovered damaged after the Columbia STS-107 tragedy, these experiments have demonstrated that microorganisms and certain other classes of terrestrial life (such as plant seeds and fungus) are not destroyed by exposure to the space environment. Only two, however, flew outside of the magnetosphere, Biostak 1 for 11 days and Biostak 2 for 12 days. While other experiments flew for longer times (the LDEF exposed spore of the bacterium Bacillus subtilis to space for six years and some survived), they flew well within the Earth’s magnetosphere, so the radiation exposure was much lower than it would be during a Mars-Earth trajectory of similar duration.
Experiment Size and Design
What is the size of the experiment?
In order to fit have as little impact upon the Phobos sample return mission, and to fit within the sample return capsule (note that it will not be in the actual canister containing Phobos samples for return), the outer envelope will be 56 mm in diameter with a maximum thickness of 18 mm. Mass will be 100 grams or less for the entire bio-module. The current design is a short cylinder, looking much like a hockey puck, but smaller.
What are other current design constraints?
The Bio-module will provide 30 small (3 mm diameter) cavities for individual microbe samples. It will also accommodate a native sample of bacteria -- derived from a permafrost region on Earth -- within a cavity 26mm in diameter. The Bio-module must be sealed to meet planetary protection requirements and experimental validation. The module must also be able to withstand a single 4000g impact (as in landing on Earth) without the seals failing or the outer case fracturing. There must be a simple means of recording radiation doses and temperature extremes during its flight and return to Earth.
What is the current engineering design of the Bio-module experiment, and what materials do you plan to use?
Our design is compact, rugged and simple. Maximum mass, sample requirements, resistance to seal failure and case breach are strict requirements controlling this design. We are using strong, lightweight materials, structural integration, and multiple sealing techniques. A preliminary design diagram is shown here and much more information on the design, materials, and rationale for those can be found on our current design page.
The LIFE experiment, exploded view
Credit: The Planetary Society
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What organisms do you plan to fly and why?
The exact organisms to be included are still under analysis, but will include microbes that have been flown in near-Earth space on short missions, microbes that have been studied extensively, microbes that are resistant to environmental factors such as radiation, well-studied plant seeds, and a “natural” soil colony of microbes. None of the microbes will be dangerous to humans. We plan to fly representatives of all three domains of life: bacteria, eukaryota, and archaea. We anticipate flying 10 individual organisms in 30 self-contained samples, i.e., each will be flown in triplicate for better science results. In addition, one or more natural native soil samples will be flown in their own self contained capsule.
If any of the microbes survive, how will you know they are the same microbes you intended to send from Earth, rather than contaminants?
Some of the things under consideration to avoid this include:
- the multiple seals used in the canister
- separate sealed tubes for each biological sample within the canister
- impact and other testing to insure that the container won’t break at any time, including landing on Earth
- choosing unusual strains of each organism that you wouldn’t find as typical lab contaminants (e.g., on people’s hands, in sneezes, or in the labs while the samples are loaded)
- Sterilizing the canister before loading the biological samples
- Sterilizing the surface of the canister before unloading the biological samples
- Following standard sterility lab procedures to avoid contamination.
Planetary Protection:
Are any of the microbes being flown dangerous to humans?
No. None of the microbe strains being selected will be dangerous to humans
Could these microbes mutate in space and return as dangerous microbes?
Dangerous mutation is extremely improbable because we are sending only desiccated, inactive microbes without sources of nutrition and energy, and they will not be reproducing. To create evolutionarily successful mutations, an organism needs to reproduce. The development of evolutionarily successful mutations, good or bad, requires conditions favorable to microbial growth. In order to give the microbes maximum chance of surviving the trip, the LIFE experiment requires that the microbes travel in a desiccated, inactive, non-replicating state, the exact opposite of what’s needed to change a microbe gene pool in any meaningful way.
All our organisms will be non-pathogenic (do not cause disease). To change these benign organisms -- without the forcers of natural evolution and by random chance -- to generate dangerous and viable organisms is incredibly improbable.
Even with the very low probabilities, we will take great care with the samples and follow standard biological protocols to always err on the side of extreme caution. And, as in all aspects of this experiment, we will get external review of our analyses and plans.
Is it likely that this experiment could contaminate Mars with life, thus confusing future searches for life on Mars?
The short answer is that it is very unlikely, but we are doing a thorough analysis of the issue. We will fully comply with the COSPAR (Committee on Space Research of the International Council for Science) planetary protection guidelines aimed at preventing the contamination of Mars by introducing terrestrial life onto the surface of Mars. We have begun an analysis of failure probabilities that could lead to accidental introduction of life to Mars. Preliminary indications are that these probabilities will be very, very small and will be well within COSPAR guidelines, but we are continuing a more thorough analysis, including getting outside expert review. After that is completed, we will make the analyses available publicly via The Planetary Society web site, and before the Phobos-Soil mission, we plan to publish a peer-reviewed paper documenting this analysis.
Mars meteoroid facts:
- About 1 Martian meteorite is thought to hit Earth every month.
- About a billion tons of Martian rock have landed on Earth since the solar system formed.
- About 30 Martian meteorites have been identified on Earth.
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