A crew of miniature mammals will go where no humans have gone before, into space for the specific purpose of procreation, if a private space exploration group can make the mission fly. The proposed two-month orbital flight would allow enough time for the mice-stronauts to reproduce and the young to become adults, according to the Mars Society. The experiment would place the orbiting animals in an environment that simulated the gravity of Mars, about one third that of Earth, in order to help plan long-term manned missions to the red planet.