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.
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.
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.