Experiments and Biological Assays on Microorganisms Subjected to Impact Stresses

Abstract Introduction The search for signs of life outside of Earth is an important motivation for many space missions. However, the risk of contamination of planetary bodies that may have harbored extraterrestrial life needs to be mitigated; any biosignatures detected cannot be conflated with those produced by organisms brought to the planetary body from the Earth spacecraft. Likewise, contamination from return samples to Earth may pose a harmful threat to humans and Earth life. Therefore, adequate planetary protection policy is necessary to mitigate these concerns. Consider for example the upcoming Martian Moons Exploration (MMX) mission, which aims to better characterize Deimos and Phobos, the two moons of Mars, and bring back samples from Phobos. However, could there be Martian life in the samples from Phobos? An asteroid impact on Mars could potentially emplace ejecta on Phobos, and Martian life (if any) in the fractured rock could perhaps survive and spread to Phobos through the ejecta. Could organisms survive the impact? Since impact processes heavily affect all planetary bodies, its potential to affect the introduction, spread, and presence of life across the solar systems needs to be understood.