Artemis II reentry and the risks of ‘riding a fireball through the atmosphere’
After glorious lunar views, a moving dedication, a malfunctioning toilet, and a floating Nutella, Artemis II is poised for the riskiest part of its 10-day journey to the far side of the moon.
The Orion spacecraft, Integrity, is slated to enter the Earth’s atmosphere tonight at 7:45 EDT at a blistering 25,000 mph and 5,000 degrees Fahrenheit. The autonomously guided capsule will slow down and dissipate heat through a time-honored “skip” maneuver that dips it in and out of the atmosphere in a suborbital arc, then back in again for a final descent. Think of skipping a stone on the water’s surface to slow it down.
The technique involves shifting Orion’s center of mass by rotating it left and right to generate lift before reentering the atmosphere a second time, thereby achieving a safer speed for parachute deployment and lower g-forces for a crew acclimatized to microgravity. Adjusting the reentry timing and angle enables a more precise landing target.
It will take roughly 40 minutes from when the service module separation takes place at 400,000 feet (76 miles) to splashdown 50 to 80 miles off the coast of San Diego, including a nail-biting six-minute communications blackout with Mission Control at Johnson Space Center in Houston.
“We have high confidence in the system, heat shield, and parachutes, and recovery systems we put together. And tomorrow the crew is going to put their lives behind that confidence,” Amit Kshatriya, NASA associate administrator, said during a press conference on April 9.
Orion’s reentry will stream on NASA’s YouTube channel, NASA+, and its other social media platforms, as well as on C-SPAN.org beginning at 6:30 p.m. EDT for the anticipated splashdown at 8:07 p.m. The descent might be visible in Southern California as a slow-streaking shooting star. It’s more likely to capture attention with a widely felt sonic boom.
NASA’s Reid Wiseman, Victor Glover, and Christina Koch, and the Canadian Space Agency’s Jeremy Hansen are the first astronauts to travel to the moon in more than 50 years. And their journey took them farther from Earth—nearly 250,000 miles—than any other human has ever traveled. The mission tees up subsequent flights to the lunar surface to establish a sustainable base.
“This is a relay race,” Koch said of the crew’s attitude toward future missions during an April 8 in-flight press conference. “We brought batons to symbolize [that] physically. We plan to hand them to the next crew, and every single thing that we do is with them in mind.”
Reentry is considered more dangerous than launch—like “riding a fireball through the atmosphere,” noted Glover. Aside from the extreme heat, there are fewer options to mitigate failure and none to abort. Reentry from the moon is faster than from low-Earth orbit, requiring more parachutes. Following a finding that parts of the Artemis I heat shield degraded more than expected upon reentry, Artemis II will engage a shorter entry range.
Yet even with this adjustment, retired astronaut and thermal protection expert Charles Camarda and former NASA engineer Daniel Rasky have raised grave concerns about the heat shield’s efficacy. Camarda unsuccessfully lobbied to help NASA revise the shield, estimating a 1 in 20 chance of disaster (which translates to a 95% success rate), while Rasky told ABC News, “If I had to rate it an A, B, C, D, or E, I’d rate it an F.”
“We have to get back,” Glover said. “There’s so much data that you’ve seen already, but all the good data is coming back with us. There are so many more pictures; so many more stories.”