A joint Mars exploration program between NASA and European Space Agency (ESA) has set a long term focus of the return of samples from Mars to Earth.
The current proposed campaign calls for a set of three missions.
The Soviet Union's Luna program pioneered the field of robotic sample return. The Luna 16 mission to Earth's Moon was the first successful robotic sample return.
No spacecraft has returned samples from the surface of another planet, though meteorites from Mars have been found on Earth (above).
Scientists on Earth can make a more thorough analysis of samples than can be made on a distant planet.