Potential microbial transfer from Mars to its moons and even to Earth could be brought about by transportation of Mars ejecta produced by past gigantic meteoroid impacts on Mars. To answer this question, potential microbial transfer processes have been assessed, based on the most probable history of the recent major gigantic meteoroid impacts on Mars. Potential microbial density on Mars was estimated by analogy from the terrestrial areas having the similar arid and cold environments. Mars ejecta transportation from Mars and impact onto the Martian moons are numerically simulated by the Smoothed Particle Hydrodynamics (SPH) method and associated trajectory analysis in a Monte Carlo manner, taking sterilization by hypervelocity impacts and cosmic radiation into consideration, to obtain a statistical estimate of the microbial density survived on the current surface of the Martian moons. The potential number of microorganisms transferred to Earth through the same processes was estimated as well.


Prof. Fujita got a Ph.D. at Graduate School of the University of Tokyo in 1995. Then he became a research associate at the Institute of Space and Astronautical Science, and was engaged upon fundamental researches on nonequilibrium aerothermodynamics, radiation, rarefied gasdynamics, and plasma dynamics associated with planetary entry vehicles. He moved to Research & Development Directorate, the Japan Aerospace Exploration Agency (JAXA) in 2003. He has been a visiting professor at Graduated School of University of Tokyo since 2013, and a professor at the Institute of Space and Astronautical Science, JAXA since 2018. His group is engaged in technology development for planetary exploration, such as atmospheric entry system, aeroassist guidance, and planetary landing. In this context, his group has been actively conducting planetary protection and astrobiology researches for Mars exploration in recent years.