NASA’s Artemis II astronauts are closing in on the trip back to Earth, approaching what many consider the riskiest part of their lunar flyby: atmospheric reentry.
The mission lifted off on 1 April and is scheduled to wrap up on 10 April, when the crew — NASA astronauts Reid Wiseman, Victor Glover, and Christina Koch, alongside Canadian astronaut Jeremy Hansen — is due to return through Earth’s atmosphere.
Reentry is especially unforgiving because Orion depends on a single thermal protection system to survive the searing heat generated as it hits the upper atmosphere.
On the way home, Orion will descend to roughly 76 miles above Earth before its service module separates from the crew capsule. From there, the capsule will dive into the atmosphere at close to 25,000 miles per hour.
At those velocities, air rapidly compresses in front of the vehicle, driving external temperatures on the capsule to nearly 5,000°F (2760°C).
As the heating peaks, a shell of superheated gas — plasma — forms around Orion. That layer blocks radio transmissions, meaning the crew and mission control will be unable to communicate for several minutes.
Speaking at a press conference earlier this week, NASA Administrator Jared Isaacman pointed to the enormous energy involved in the mission. The Space Launch System (SLS) — a heavy-lift rocket generating 8.8 million pounds of thrust at liftoff — accelerated Orion toward the Moon, and that energy must ultimately be shed safely during the return through Earth’s atmosphere.
“In terms of what keeps me up at night, my blood pressure will be elevated until they’re under parachutes in the water off the West Coast,” he said.
“There’s no plan B there. That is the thermal protection system. The heat shield has to work,” he added.
“I have no doubt the team did a great analysis, made the most of things,” Isaacman continued.
Once the most extreme heating is over, Orion will deploy two drogue parachutes that slow the capsule to around 300 miles per hour. Pilot chutes will then follow, ahead of three large main parachutes that reduce descent speed to about 17 miles per hour for a Pacific Ocean splashdown.
Isaacman also said NASA is working to improve production across current programs, aiming to move closer to the Apollo-era approach of building additional spare hardware and retiring components that appear questionable.
“I have no doubt the team did a great analysis, made the most of things,” Isaacman continued.
“Most of the heat shields that we have available are not the right way to do things long term,” he added.
“And we are fixing it going forward. That’s why we’re increasing production rate, getting back into a good rhythm, getting a little bit closer to goodness there. But it is definitely an area we will all be thinking about until they’re on the water.”
The crew is now on its way back after completing a six-hour lunar flyby, which included views of the Moon’s far side — the hemisphere that always faces away from Earth.
The flyby also eclipsed the distance record associated with Apollo 13 in 1970, when that crew reached 248,655 miles from Earth. Artemis II went thousands of miles farther, a milestone Isaacman highlighted as historic.
“On the far side of the Moon, 252,756 miles away, Reid, Victor, Christina and Jeremy have now travelled farther from Earth than any humans in history and now begin their journey home,” Isaacman said in a statement on Twitter/X.
Artemis II has reached its maximum distance from Earth.
On the far side of the Moon, 252,756 miles away, Reid, Victor, Christina, and Jeremy have now traveled farther from Earth than any humans in history and now begin their journey home. Before they left, they said they hoped…
— NASA Administrator Jared Isaacman (@NASAAdmin) April 6, 2026
“Before they left, they said they hoped this mission would be forgotten, but it will be remembered as the moment people started to believe that America can once again do the near-impossible and change the world.”
Isaacman added that the mission ‘isn’t over until they’re under safe parachutes, splashing down into the Pacific.’