Artist’s Concept of Earth Return Orbiter Releasing Capsule Containing Martian Samples

The Earth Return Orbiter (ERO) is one of the flight missions making up the Mars Sample Return campaign to bring martian rock and atmospheric samples back to Earth. The ESA orbiter would be the first interplanetary spacecraft to capture samples in orbit and make a return trip between Earth and Mars.

The primary mission of the European spacecraft would be to find, fly to, and capture a volleyball-sized capsule called the Orbiting Sample (OS) container launched from the surface of Mars by NASA’s Mars Ascent System and carrying a carefully selected set of samples previously collected on the surface of Mars by NASA’s Perseverance rover.

Having already spent three years to reach Mars and perform its rendezvous and capture mission, ERO would take a further two years to fly from its operational orbit around Mars up to escape altitude and make its way back to Earth. When ERO is about three days from Earth, the Earth Entry System (EES) carrying the OS would separate from the spacecraft and be placed on a precision trajectory for Earth entry and landing.

The Earth Return Orbiter is part of the multi-mission Mars Sample Return campaign being planned by NASA and the European Space Agency (ESA).

For more information, visit: mars.nasa.gov/msr.