Mars sample return mission. Illustration of the Earth Return Orbiter spacecraft (left) returning a sample to Earth (upper right) from Mars (not seen) as part of a proposed Mars sample return mission. The Earth entry vehicle (upper right) has been jettisoned from the main spacecraft (left). NASA and the European Space Agency are collaborating on proposals for missions to gather samples of Martian rocks and bring them to Earth after 2020. These missions include Mars 2020, Sample Retrieval Lander, Sample Fetch Rover, Mars Ascent Vehicle, and Earth Return Orbiter (shown here).