The Living Interplanetary Flight Experiment
An opportunity to explore the Mars-to-Earth transpermia scenario
Sep 22, 2009
Is it possible that life on Earth did not emerge here, but got started from seedlings carried inside meteorites from Mars? The hypothesis, called transpermia, is intriguing, and will be put to a test beginning in the year 2011.
In an initiative of the Planetary Society, a group of scientists will send a collection of life forms on a 34-month trip to the Martian moon, Phobos, and back. Why to Phobos? The simple answer is that the Russian Federal Space Agency, Roscosmos, is allowing the organisms to hitch a ride on a probe known as Phobos-Grunt. Designated the Living Interplanetary Flight Experiment (LIFE), the collection of tiny astronauts was loaded into a canister in June 2009, because initially, the Grunt probe was scheduled for launch in October of the same year. Tight schedules and a narrow launch window, allowing for departure from Earth only every 26 months, led Roscosmos to delay to the 2011 date. But rational for the LIFE experiment will not change.
What is Known about Interplanetary Transfer of Living Organisms?
As this writer and his co-author, Ben Weiss, noted in the article "Did Life Come from Another World?" (Scientific American, 2005), from studies of several meteorites identified as having originated on Mars, scientists have determined that some microorganisms could survive catapulting from a Mars-sized planet by a comet impact. Similarly, it’s known that organisms embedded within a rock traveling through space could survive entry through Earth’s atmosphere. If life also can survive a transfer through interplanetary space, the final piece of the transpermia puzzle will be in place. Because of the short transit times possible at least for a fraction of space traveling rocks, the Grunt probe, providing nearly three years in interplanetary space, is a good simulation of a Mars-to-Earth transpermia scenario.
The LIFE Experiment
Crafted of titanium, weighing approximately eighty grams, the LIFE canister, described in detail on the Planetary Society's Living Interplanetary Flight Experiment site, holds ten distinct species in triplicate samples within thirty tiny tubes. Included are various bacteria, extremophillic (loving "extreme" environments) archaea, yeast, plant seeds, and tiny invertebrate animals called tardigrades, but known commonly and affectionately as water bears. Also included is a sample of soil from the Negev Desert in Israel (though this is a Russian component of LIFE), containing a mixed population of microorganisms. The LIFE team is extremely international; scientists involved come from the U.S., Russia, Germany, Sweden, and Turkey.
Previous Experiments Dealing with the Survival of Biological Species in the Space Environment
While there have been dozens of experiments studying the effects of space flight on life over the last four decades, nearly all have been carried out in low Earth orbit (LEO), where magnetic shields known as the Van Allen Belts protect organisms (including humans) from the charged particle component of space radiation. Two experiments, Biostack 1 and 2, did fly on Apollo 16 and 17, respectively, and thus outside the protected region. Biostack included some of the organisms which now sit within the Phobos-LIFE canister, and some of the organisms survived well. Both of these missions, however, had a duration of less than two weeks, not long enough to simulate a Mars-to-Earth transpermia scenario, not close to the 34 months that the LIFE canister will spend in interplanetary space.
How LIFE Works
There is not just one LIFE canister, but four. Two of these were loaded as ground controls so that, upon return of the flight canister, the team can compare the effects. One canister was loaded as a back-up. And finally, there is the flight canister, which now is integrated into the Grunt probe. Given the delay until 2011, the LIFE team must decide what to do with the loaded canisters. One possibility is that they may be sent on low orbital flight so that effects on the organisms can be compared with those that may be observed after new canisters are loaded in 2011.
Potentially, LIFE can reveal only whether a Mars-to-Earth transpermia scenario is possible; finding out whether it actually happened will require follow-up probes and perhaps studies of soil brought back from Mars. It could turn out that life on the two planets is related, or, alternatively, that Martian organisms emerged independently of terrestrial life.
The latter case would suggest that abiogenesis, the genesis of life from non-living matter, can occur with ease throughout the cosmos, and more. At last, biologists would be able to compare Earth organisms with alien forms and develop a more general definition of life. At last, humanity would begin to understand the laws of biology, not as a special case on a single planet, but more like the laws of chemistry and physics – as fundamental properties of nature.
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