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ERO will reach Mars orbit, capture orbiting samples launched from the Red Planet and bring them back to Earth

Earth Return Orbiter

The first spacecraft to bring samples from Mars to Earth

  • The Earth Return Orbiter (ERO) is a key element in the European/U.S. Mars Sample Return Campaign
  • ?ERO’s lift-off is set for 2026 on an Ariane 64 launcher
  • Airbus is the ERO prime contractor
  • ERO benefits from Airbus’ autonomous rendezvous and docking expertise, flight-proven technologies and interplanetary mission experience


Airbus was selected in 2020 by the European Space Agency as prime contractor for the Earth Return Orbiter (ERO) spacecraft. The ERO is a key element of the joint European/U.S. Mars Sample Return Campaign – a set of three separately-launched missions to achieve the objective of bringing Mars samples to Earth before the end of 2031.

The ERO’s five-year mission will begin with its 2026 launch by an Ariane 64 from French Guiana. Once in orbit around Mars, ERO will act as a communication relay for surface missions of the Mars Sample Return campaign, and is to receive samples brought up from the Red Planet for the flight back to Earth.

For ERO, Airbus will apply the autonomous rendezvous and docking capabilities gained during decades of space optical navigation expertise. This includes technologies from its ATV (Automated Transfer Vehicle) cargo spacecraft that serviced the International Space Station, along with the knowledge gained in developing Europe’s first mission to Jupiter, JUICE.


ATV-5 “Georges Lema?tre” in space

ATV-5 “Georges Lema?tre” in space

With a mass of six tonnes at lift-off from Earth, the six-metre-tall ERO spacecraft will have solar arrays covering a surface of 144 sq. metres and spanning more than 40 metres – among the largest ever built. During the ERO’s year-long voyage to Mars, solar electric propulsion will be employed for the cruise, followed by chemical propulsion for Mars orbit insertion. Solar electric propulsion will be utilised once again as ERO spirals down to a targeted circular rendezvous orbit at approximately 400 km. above the Mars surface.

While orbiting the Red Planet, the ERO is to provide communications coverage for the Perseverance Rover and the Sample Retrieval Lander – both developed by the U.S. National Aeronautics and Space Administration (NASA), which are two essential parts of the overall Mars Sample Return Campaign.

For the ERO mission’s second phase, the orbiter will detect, rendezvous with, and capture a basketball-size object called the Orbiting Sample (OS), which carries sample tubes collected on the Mars surface by the Sample Fetch Rover – an Airbus-developed four-wheel vehicle that will travel the planet to locate and pick up these samples.?

The Orbiting Sample will be carried aloft by a Mars Ascent Vehicle to meet up with the ERO.? After the Orbiting Sample’s rendezvous with ERO, an onboard Capture, Containment, and Return System (supplied by NASA) is to isolate the Orbiting Sample and transfer it within the ERO to an Earth Entry Vehicle (also supplied by NASA). Following a year-long return trip to Earth, ERO will deploy the Earth Entry Vehicle for touchdown at a pre-defined landing site.

In Airbus’ role as ERO’s prime contractor, the company will have overall responsibility for the orbiter’s mission, with spacecraft development centred in Toulouse, France, and mission analysis performed in the UK at its Stevenage operation.

The first spacecraft to bring samples from Mars to Earth
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