The crew of Artemis a few hours from returning to Earth

After a flight around the Moon rich in highlights and symbols, the four astronauts of the Artemis II mission must recross the Earth's atmosphere and land on Friday evening off the coast of California, a last moment of truth for NASA.

“We can start to rejoice when the crew is safe” on board the ship responsible for retrieving him, insisted Amit Kshatriya, deputy administrator of NASA during a press conference on Thursday.

"That's really when we can let the emotions take over and start talking about success."

After venturing more than 406,000 km from us, further than anyone before them, the Orion capsule carrying the Americans Christina Koch, Victor Glover and Reid Wiseman and the Canadian Jeremy Hansen must land off the coast of San Diego around 5:07 p.m. local time (00:07 GMT Saturday).

The landing must complete this ten-day mission which has taken place so far with perfect execution. A safe return would provide NASA with the relief of having succeeded in sending astronauts back into space, for the first time since the end of the Apollo program in 1972, after years of delays and doubts.

A success which requires that Orion's heat shield resists the 2,700°C generated by friction with the atmosphere upon return.

- "Fireball" -

“Crossing the atmosphere like a ball of fire” will constitute a “marking” experience, noted pilot Victor Glover earlier this week, confident that he has been dreading this moment since his selection into the crew in 2023.

If this stage is always delicate for astronauts returning from the International Space Station, concerns are reinforced this time by the fact that this is the first manned flight of Orion, and that a problem was detected during an empty test in 2022.

During the return to Earth, the heat shield protecting the ship had deteriorated in "an unexpected way" according to a technical report.

Despite this anomaly, the American space agency decided to continue with the same shield, reviewing the trajectory in order to choose a more direct angle of entry into the atmosphere, to limit the rebound which had contributed to deteriorating the heat shield.

A decision which has caused a lot of ink to be spilled and which continues to haunt NASA's highest officials.

“I'm going to think about it non-stop until they're in the water,” NASA chief Jared Isaacman recently admitted in an interview.

"It's impossible to tell you that there remains no irrational apprehension," admitted his right-hand man on Thursday, while ensuring that he had no rational fear on this subject.

Insisting on the multiple tests, simulations and modeling carried out, NASA officials assure that they have confidence in the calculations of their engineers and have