Despite extensive cleaning operations to remove terrestrial life from space missions, microbial life have nonetheless manage to reach and survive in space, which compromise the success of some missions. But the researchers have finally found the flaw. It’s in the cleaning products themselves…
In spacecraft assembly plants, oligotrophic and low moisture environments are found. And cleaning operations with alcohol and alkaline detergents are implemented regularly. All in order to avoid contaminations by terrestrial organisms, especially when preparing for life-detection missions on another planet.
Despite these precautions, a basic microbiome seems to persist. Bacteria, archaea and fungi can often be observed on the spacecraft and equipment used for the missions, acinetobacter constituting the dominant population. And it is precisely Acinetobacter strains from Mars Odyssey and Phoenix that researchers at California State Polytechnic University (USA) have studied to understand to mystery.
Acinetobacter – seen here under the electron microscope – is a kind of bacterium that engineers have a hard time eliminating from spacecraft. And for good reason, they seem to eat the cleaning products the scientists use. © CDC’s Public Health Image Library, Wikipedia, Public Domain
Researchers discovered that, to survive an environment in which the amount of nutrients is restricted, this kind of bacteria grows thanks to the cleaning agents used to eliminate them! They indeed grew under conditions in which ethyl alcohol was the only possible source of carbon. And these cultures also had a reasonable tolerance for oxidative stress.
The strains tested were also able to exploit the resources of isopropyl alcohol or Kleenol 30, another cleaning product very commonly used by NASA. Products that prove to be interesting sources of energy for this particular microbiome.