http://www.sciencemag.org/news/2019/11/bold-space-mission-bring-back-rocks-mars-takes-shape

Europe's Earth return orbiter must track and snare the orbiting sample sphere.

In just over a decade, a small capsule shaped like a flying saucer will blaze in from space and smash into an empty Utah desert. Inside the capsule, protected by shock absorbers, will be a precious payload: about half a kilogram of rocks gathered on Mars. After years as a dream, Mars sample return (MSR) is now a $7 billion plan, devised jointly by NASA and the European Space Agency (ESA). Involving three heavy rocket launches from Earth, two rovers, the first ever rocket launch from another planet, and a daring rendezvous between the sample container and a spacecraft that would ferry it back to Earth, "It's as complicated as sending humans to the Moon," says Brian Muirhead, lead MSR planner at NASA's Jet Propulsion Laboratory in Pasadena, California.