NASA's Artemis 1 Orion spacecraft will depart lunar orbit on Thursday afternoon (Dec. 1), and you can watch the action live.
The uncrewed Orion is scheduled to perform a crucial 105-second engine burn on Thursday at 4:54 p.m. EST (2154 GMT), which will send the capsule out of orbit around the moon and mark the beginning of its long journey back to Earth.
NASA will provide coverage of the milestone live, beginning at 4:30 p.m. EST (2130 GMT). Watch it live here at Space.com or directly via the space agency (opens in new tab).
As its name suggests, Artemis 1 is the first flight in NASA's Artemis program, which aims to establish a crewed base near the lunar south pole by the end of the 2020s.
Artemis 1 is a shakeout cruise for both Orion and the SLS, a way to demonstrate that both vehicles are ready to carry astronauts into deep space. If all goes well with the current mission, Artemis 2 will send astronauts around the moon in 2024 and Artemis 3 will put boots on the lunar surface a year or so later.
And things have been going well so far; the SLS did its job on Nov. 16, and Orion has been checking off boxes ever since. One of the most important milestones was insertion into a distant retrograde orbit (DRO) around the moon, which the spacecraft achieved with an engine burn on Nov. 25.
On Wednesday (Nov. 30), the Artemis 1 team held a meeting to determine whether or not Orion is ready to leave DRO, and the result was unanimous.
"All of our mission management team members polled go for returning Orion back to the Earth," Artemis mission manager Mike Sarafin said during a press conference on Wednesday evening.
So Orion's time in DRO will come to an end on Thursday. The capsule will still have a fair bit of spaceflying ahead of it, however: Orion isn't scheduled to land on its home planet until Dec. 11.
On that day, the spacecraft will splash down under parachutes in the Pacific Ocean off the coast of California. NASA and the U.S. Navy are already training for the homecoming, practicing the recovery operation that will wrap up the Artemis 1 mission.
Mike Wall is the author of "Out There (opens in new tab)" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall (opens in new tab). Follow us on Twitter @Spacedotcom (opens in new tab) or Facebook (opens in new tab).