Stardust, Haybusa, and the Andromeda Strain
Published on Dec 6, 2005 at 7:53 pm.
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Filed under asteroids, comets, science fiction.
In 1969, as NASA prepared to land the first manned mission on the Moon, the public was introduced to a science fiction novel written by Michael Crichton called The Andromeda Strain. This was later made into a movie. The premise of the story is that a space probe returning to Earth brought back some sort of deadly alien organism (the Andromeda strain) that had a nearly 100% mortality when humans were exposed to it. This was not really so far fetched of a worry, perhaps, since when Europeans came to the new world, they brought diseases with them that the local population had no natural immunity or resistance to. The diseases, together with war, killed the bulk of the population of MesoAmerica within a generation. NASA was also cognizant of this, and there was worry that perhaps some organism on the Moon that humans have never been exposed to and have no immunity to would run rampant on Earth in a pandemic of untold proportions. Now, most molecular biologists and immunologists rather discounted this idea, saying that any organism that has never been exposed to humans would not have developed any way to attack us. Our immune systems protect us from all but those germs that adapt to find a way around the immune response (even if only temporarily). Still, one can’t be too careful, NASA reasoned. So, for both Apollo 11 and Apollo 12 (the first two manned missions), the astronauts were quarantined upon arrival back on Earth. On the recovery ship, they went into a sealed travel trailer and stayed there until the trailer was brought back to Houston, where they exited into a hermetically sealed laboratory together with the moon rocks. They were kept there until it was determined that they had no disease whatsoever. Soon, however, it was determined that the Moon is absolutely sterile, and there are no Moon organisms at all. The only exception was when Apollo 12 landed next to Surveyor 3 and returned some instruments from the unmanned craft that NASA scientists found streptococcus spores on the instruments, presumably from one of the technicians assembling it. The spores had somehow remained viable in the unbelievably harsh environment of space! Later manned Moon landings did not have to go through the quarantine procedure.
Now, interestingly enough, two unmanned space probes are returning to Earth with samples from space. One, an American probe named Stardust, is returning samples from a comet. The other, a Japanese probe called Haybusa, is returning (hopefully) samples of an asteroid. Both of these bodies are quite different from the Moon. The Moon has no organic molecules making up its rocks. However, comets have been known for over a century to be composed of large amounts of organic molecules. Meteorites believed to have come from asteroids have been found to contain organic molecules, and the spectrum of many asteroids shows a composition that includes organic molecules. Now, we can not say that this means that these bodies have life on them. Here I am using the term “organic” in the way of chemists, in that it means carbon based molecules. However, life is carbon based. Under the harsh radiation environment of space, these molecules break down and recombine into other forms. Some rather complex molecules can form, including even amino acids. These can be the building blocks needed for life. Again, there is nothing that would indicate the presence of live, and plenty to indicate its absence. However, this is interesting in that these probes are the closest that we have actually come to the scenario at the beginning of Crichton’s book. It is particularly ironic in that in the book, the sample container is compromised upon return to Earth, which is exactly what happened to the samples of solar wind particles returned to Earth by the Genesis mission!
The samples returned will be handled with extreme care, as with the moon rocks, but more to protect them from contamination with Earth organisms than with their contaminating Earth. Besides, meteorites fall to Earth all the time from these bodies, so if the did contain organisms, then those organisms would already be here. We don’t seriously expect to find life, and if we did it would be one of the biggest shocks that the field has ever had. But, I figured that it might be interesting to point out the connections of science fact and science fiction, remembering of course that science fiction is just that: fiction.
-Astroprof
