The Orion capsule of the United States Space Agency is returning home.
The vehicle conducted a large engine burn near the lunar surface on Monday, committing it to a splashdown in the Pacific Ocean on Sunday.
It was the next-generation crew ship’s final significant powered maneuver on what has been an extremely successful demonstration flight so far.
After a smooth return this weekend, astronauts will board Orion for its next trip in late 2024.
As part of its Artemis program, Nasa is planning a series of more difficult missions for the capsule and its launch rocket.
Artemis-1, the initial trip, has been all about testing technologies in the absence of people. They’ll get their chance on the following mission, Artemis-2.
The most anticipated mission is Artemis-3, which will aim to put people on the lunar surface for the first time in more than 50 years. It could happen in late 2025 or early 2026.
But the whole plan depends on the current venture ending without incident.
Orion set off from the Kennedy Space Center in Florida on 16 November. It was put into an extended loop around the Moon that saw it reach some 430,000km (270,000 miles) beyond Earth – the furthest any spacecraft designed to carry humans has travelled.
Two big engine firings from Orion’s European Space Agency-provided propulsion unit – the first occurring last Thursday, and the second in the past few hours – have since turned the ship home.
Nasa is describing the return as its “priority one” for the mission. Engineers want to see proof that the vehicle can survive the heat of re-entry into Earth’s atmosphere.
Orion will be moving at about 39,500km/h, which is far faster than a spacecraft coming back from the International Space Station.
As the vehicle pushes up against the air in front of it, pressure and friction will generate temperatures approaching 3,000C.
Nasa and spacecraft manufacturer Lockheed Martin need to know the shield on the capsule’s underside is absolutely fit for purpose before astronauts are asked to ride aboard.
Assuming the shield works and the 11 parachutes deployed to further slow the spacecraft also work, a controlled splashdown off the California coast should occur not long after 09:30 local time (17:30 GMT) on Sunday.
