Scientists have been conducting experiments with microbes attached to the outside of the International Space Station and have learned that they can survive for at least three years. The finding suggests that microbial life can survive a journey through space from Earth to Mars. Scientists Akihiko Yamagishi at Tokyo University of Pharmacy and Life Sciences in Japan says that the study proves bacteria can survive in space and could be transferred from one planet to another.
One of the major concerns for NASA is that humans could contaminate other planets and bodies in space with bacteria from our planet. Yamagishi says that scientists don’t know if life emerged on Mars and could have been transferred to earth, meaning that we could be the offspring of Martian life. He also says that if the journey is possible between Earth and Mars for bacteria, finding life on planets outside our solar system increases.
The bacteria NASA is using in its study is called Deinococcus radiodurans, which are naturally very resistant to radiation because of its capacity to repair DNA when it gets damaged. One main goal of the study was to determine if the bacteria could survive the harsh environment of space where radiation levels, particularly in the ultraviolet range, are extremely high.
The researchers sent cell clumps of various thicknesses to the International Space Station, where they were placed on aluminum plates and attached to the outside of the spacecraft for three years. Samples were collected and sent back to earth every year for analysis.
Inside clumps of at least half a millimeter thick, the researchers found surviving bacteria even in samples are left outside the space station for three years. Researchers thought that the ultraviolet light would kill the bacteria due to its strength. The UV destroyed the bacteria in the outer layer of the clumps with the dead cells shielding bacteria in the innermost layers allowing them to survive.