14 DAY TRIAL // When the Mars Science Laboratory (MSL) rover Curiosity will launch later this year, it will carry with it a rather high risk of cross-contamination. The term is used to refer to instances when life indigenous to a celestial body makes its way to another cosmic object.
In the early days of space exploration, NASA was for example very concerned that returning spacecraft may have brought back alien lifeforms, so strict quarantine and cleaning procedures were set in place.
As the time passed, experts realized that it was more likely for life originating here to be spread to the other objects inside our solar system. As such, strict cross-contamination measures were set into place, with the sole purpose of preventing spacecraft from taking microbes or bacteria to other planets.
In a recent study, experts show that Curiosity's wheels are more likely to allow microorganisms to endure than any components in other Mars-bound missions. This difference is mostly due to the innovative landing system that the American space agency plans to use.
The precise combination of factors and environmental conditions characterizing the Sky Crane system makes it likely that some microbes will make it to the Martian surface. Though they will most likely not live for a long time, the organisms will leave traces behind.
Bacteria are extremely resilient lifeforms, as demonstrated in countless studies. Some of them can survive clean room sterilization procedures, months-worth of exposure to cosmic rays, and even the extreme environment characterizing the Martian surface.
University of Florida microbiologist Andrew C. Schuerger says that MSL has the highest contamination risk of all missions NASA sent to the Red Planet. The expert, who led the recent study, is also based at the NASA Kennedy Space Center (KSC) Space Life Sciences Laboratory.
“Although this paper suggests we could be transferring bacteria to Martian surface, we don't know for certain yet. We could very well be losing most due to the exposure to vacuum in space, cosmic rays and hard radiation,” he explains.
“Even if cells are present on a rover wheel at launch, they might be dead by the time they get to Mars,” the investigator goes on to say, as quoted by Space. He conducted the work with colleague Krystal Kerney, and they both focused on the bacteria species Bacillus subtilis.
Details of the research effort were published in the June issue of the esteemed journal Astrobiology.
“We need to repeat these experiments with much longer time exposures to Martian conditions to see if we can get to a rover wheel completely sterilized sitting on a landing pad,” Schuerger says.
“We also need to see if seven or eight Martian days would essentially get to zero amount of survivors, even if we accidentally transferred bacterial spores to the surface,” the expert concludes.