There is a chance that the first colonizers from Earth on Mars will be bacteria. According to NASA researchers working on the International Space Station (ISS), some bacterial endospores show tremendous resistance to the various harsh aspects of outer space. In fact, Astrobiology, a peer-reviewed science journal, recently published three separate reports regarding the topic.
Essentially, tiny micro-organisms could stowaway on a spacecraft, end up on the surface of Mars, and propagate. Later, it would be difficult to decipher whether the bacteria was native to the planet. Researchers are hoping to be able to keep the numbers of these microbes down thereby making it less likely that they will survive what are typically unfriendly conditions. Unfortunately, some of the bacteria are proving to be quite robust.
One group that are proving themselves to be somewhat outer space resistant are spore-forming bacteria. These hardy little fellows have already proven to withstand various sterilization protocols and some even seem to have ways of protecting themselves during interplanetary space travel.
One such bacterial superstar is Bacillus pumilus SAFR-032. Not even peroxide treatments or ultraviolet radiation, both used for washing spacecraft, can easily kill this hardy microbe. Samples of the microbe were found on surfaces and in air particles in both classified and unclassified areas of the ISS. These conditions are unacceptable when it comes to missions regarding life-detection.
Plus, when subjected to Mars environment simulations, exposures that typically eradicate standard spores in 30 seconds, these spores endured for 30 minutes. Given the right conditions, B. pumilus SAFR-032 could become the first colonizers on Mars. Their unusual abilities to resist what other bacteria cannot have been linked to their DNA make-up. B. pumilus does not have certain stress response genes that are found in other bacteria, like B. licheniformis and B. subtilis.
Recently, these super-resistant spores were exposed on a facility for testing that is mounted on the ISS. For 18 months they were subjected to various outer space conditions like, solar radiation, fluctuations in temperature and the ever-present vacuüm of space. Some of the spores did indeed survive the entire time of exposure.
It was discovered that the spores that survived possessed higher levels of UV radiation resistant proteins. Surprisingly, these same spores, once re-exposed here on Earth, displayed even higher UV resistance. What has been confirmed is that while most of the conditions were survivable for about half of the organisms, the solar UV radiation did cause most of them to perish. This may be the key to reducing the chances of earthly bacteria contaminating other celestial bodies, like Mars.
Colonization prevention may not be possible. However, having a deeper knowledge of just what kind of micro-organisms can survive harsh exposures to space travel will go far in aiding scientists who are charged with identifying and isolating them.
The image of little bacteria being the first to colonize planet Mars is humorous. However, the gravity of the situation is palpable to the people who have the responsibility to ensure pristine conditions at all times in order to do their jobs well. NASA and the other space agencies working on the ISS are committed despite the tiny organisms that threaten to make challenging work even more challenging.
By Stacy Lamy