NASA's moon crew will hit 25,000 mph tomorrow. That's not the scariest part.
Orion will slam into Earth's atmosphere at more than 30 times the speed of sound, in what NASA expects to be the most demanding part of the Artemis II moon mission.
On landing day, Artemis II entry flight director Rick Henfling and his team in mission control will run the final leg home of the 10-day spaceflight. After wake‑up, controllers will brief the four astronauts — Commander Reid Wiseman, pilot Victor Glover, Christina Koch, and Jeremy Hansen — on weather at the splashdown zone, then clear them to secure loose gear and climb into their pressure suits.
A small final steering burn in space will aim the Orion spacecraft at a targeted patch of the Pacific Ocean, west of San Diego, California, where a Navy ship will be waiting Friday evening. On the ground, engineers will also arm backup flight software so the capsule can still guide itself through the atmosphere if its main computers fail.
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This home stretch carries extra tension following Artemis I, when pieces of Orion's heat shield unexpectedly broke off during the uncrewed test flight’s descent. Engineers later attributed the problem to hot gas building up faster than it could escape during that mission's so-called "skip" entry. But rather than redesign the shield, NASA chose to change the capsule's path through the atmosphere to avoid the hottest temperatures.
Long before launch, the heat shield was Wiseman's top concern for Jim Free, who led NASA's Artemis rocket and spacecraft programs in 2023.
"Every time you see me come in, you take a step back," Wiseman told Free at a news conference, "because I'm coming about the heat shield."
Instead of repeating the same deep bounce from the inaugural flight, Artemis II will use a gentler "lofted" approach, Henfling said. Orion will still dip in and out of the atmosphere before the final plunge, but with a less dramatic climb and fall. That change shortens the distance to splashdown and keeps the gas‑pressure spikes seen on the first flight in a tolerable range. NASA brought in an independent review team before approving the revised plan.
Glover said he's been thinking about re-entry since April 3, 2023: the day he was assigned to the Artemis II crew.
"At one of the first press conferences, we were asked what are we looking forward to, and I said, 'Splashdown,'" he said during a very long-distance call with reporters from the capsule Wednesday night. "Riding a fireball through the atmosphere is profound."
Though alarming, NASA officials said in 2024 that the damage to Artemis I's heat shield would not have harmed a crew.
"They would have not sensed any disturbance inside the vehicle, there would not have been any excessive heating on the structure, and the guidance would have put them exactly where the Navy needed to recover them," said Amit Kshatriya, a senior NASA official.
As Orion nears Earth, communications will switch from the giant moon‑tracking antennas of the Deep Space Network to near‑Earth relay satellites. About 20 minutes before entry, the service module — the section with solar arrays and the main engine — will separate and burn up over the ocean, leaving only the crew capsule to face the punishing heat.
Entry begins roughly 75 miles up, with Orion moving at 25,000 mph. Air piling up in front of the capsule will heat to about 5,000 degrees Fahrenheit, engulfing it in plasma that may briefly cut off radio contact. Inside, the crew will feel about 3.9Gs — a crushing pressure of four times his or her own weight.
Though the astronauts have often described potential records as mere distractions, Wiseman admitted there is one he has mentally clocked during their training — potentially beating previous reentry speeds by perhaps 200-or-so miles per hour. Apollo 10's velocity translated to about Mach 37, according to its 1969 press kit.
"We still giggle a little bit when we see a click over Mach 39 on entry," he said months before the April 1 launch.
Once Orion is slow enough, a tight parachute sequence will take over. A cover over the nose will blow off, two small drogues will pop out to steady the capsule, then three large orange parachutes will open in stages to cut its speed to a survivable splashdown. Small thrusters will tip the capsule so it hits the waves at the safest angle near the California coast.
After splashdown, NASA will keep Orion powered for roughly two hours to monitor how temperatures inside the capsule change as it cools in the Pacific, even after the astronauts are on the recovery ship.
Dan Flores, who is on the recovery team, may be biased but calls this his favorite part of the mission.
"We have our friends flying around the moon," he said. "This is when we get to bring our friends back home to their families."
Topics NASA
Elisha Sauers writes about space for Mashable, taking deep dives into NASA's moon and Mars missions, chatting up astronauts and history-making discoverers, and jetting above the clouds. Through 17 years of reporting, she's covered a variety of topics, including health, business, and government, with a penchant for public records requests. She previously worked for The Virginian-Pilot in Norfolk, Virginia, and The Capital in Annapolis, Maryland. Her work has earned numerous state awards, including the Virginia Press Association's top honor, Best in Show, and national recognition for narrative storytelling. For each year she has covered space, Sauers has won National Headliner Awards, including first place for her Sex in Space series. Send space tips and story ideas to [email protected] or text 443-684-2489. Follow her on X at @elishasauers.
