Nice sci-fi idea, but the surface conditions on Mars are so hostile that the poor defenseless moss would roll over and die. * Temperatures nearly always below

Nice sci-fi idea, but the surface conditions on Mars are so hostile that the poor defenseless moss would roll over and die. * Temperatures nearly always below the freezing point of water, often several hundred degrees lower. * Very small amount of air pressure, 0.6% that of earth, and no oxygen at all. * Because of the two factors above, no liquid water at the surface. * High levels of radiation directly from space (primarily the solar wind) to the surface, for lack of a global magnetic field. Astronauts visiting Mars will also need to protect themselves from this threat. Poor defenseless moss. :)