Earth Return Orbiter

This artist's impression is outdated and newer images are available on the ESA website. The image is being left online for archival reasons.

Artist's impression of ESA's Earth Return Orbiter produced in 2019. An updated version can be found here.

The Earth Return Orbiter (ERO) is one of the flight missions making up the Mars Sample Return campaign to bring martian rock, soil 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. 

NASA’s Perseverance rover is exploring the surface and storing a set of samples in canisters in strategic areas to be retrieved later for flight to Earth. Once it has collected them in what can be likened to an interplanetary treasure hunt, it will return to the lander platform and load them into a single large canister on the Mars Ascent Vehicle (MAV). This vehicle will perform the first liftoff from Mars and carry the container into Mars orbit.

ESA’s Earth Return Orbiter will be the next mission, timed to capture the basketball-size sample container orbiting Mars. The European spacecraft will find, fly to and capture a basketball-sized capsule called the Orbiting Sample (OS) 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. The samples will be sealed in a biocontainment system to prevent contaminating Earth with unsterilised material before being moved into an Earth entry capsule.

Having already spent three years to reach Mars and perform its rendezvous and capture mission, ERO will 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) with the orbiting sample capsule separates from the spacecraft and is placed on a precision trajectory for Earth entry and landing.