Mars sample-return mission gained from the "Hayabusa 2" and SLIM missions. Of the two moons, Phobos's orbit is closer to Mars and its surface may have adhered particles blasted from the red planet; thus the Phobos samples collected by MMX may contain material originating from Mars itself. Japan has also shown interest in participating in an international Mars sample-return mission. Since it is currently unknown whether life forms exist on Mars, the mission could potentially transfer viable organisms resulting in back contamination—the introduction of extraterrestrial organisms into Earth's biosphere. The scientific consensus is that the potential for large-scale effects, either through pathogenesis or
Exploration of Mars one of the proponents of such missions. Various asteroids, moons, and places on Mars can be mined while crops are initially being planted. This method will save lives on Earth, add potentially trillions of dollars to the world economy annually, and provide a stable colony on Mars. Some have also stated that persons should stay on Earth, but get food and resources from Mars and surrounding asteroids, moons, greenhouses in space and other structures. Some critics contend unmanned robots can perform better than humans at a fraction of the expense. If life exists on Mars, a human mission could contaminate