Heading home: The riskiest part of the Artemis II moon mission is still ahead

Jackie Wattles, CNNFri, April 10, 2026 at 1:32 AM UTC

0

During Artemis II's historic flyby of the moon's far side, the astronauts captured this image of a crescent Earth setting on the moon’s limb. - NASA

The Artemis II astronauts have faced down numerous dangers on their historic moon mission — including white-knuckling through liftoff on April 1 as their rocket burned through millions of gallons of fuel and braving perilous fields of radiation en route to the moon.

But perhaps the most daunting milestone lies ahead: reentry.

During this phase of flight, the astronauts’ spacecraft comes roaring toward Earth and dips back into the thick inner band of our planet’s atmosphere while still traveling more than 30 times the speed of sound. The process causes a violent compression of air molecules that can heat the capsule’s exterior to more than 5,000 degrees Fahrenheit (2,760 degrees Celsius).

“I’ll be honest and say, I’ve actually been thinking about entry since April 3, 2023, when we got assigned to this mission,” Artemis II astronaut Victor Glover said of reentry during an event with media Wednesday. “One of the first press conferences, we were asked, what are we looking forward to? And I said, splashdown. And it’s kind of humorous, but it’s literal as well — that we have to get back. There’s so much data that you’ve seen already, but all the good stuff is coming back with us. There’s so many more pictures, so many more stories.”

Reentry is considered one of the most — if not the most — precarious steps of any flight to space. And Artemis II will be going through it with a known issue mission controllers are tracking.

The problem came to light after the uncrewed Artemis I test flight around the moon in 2022, after which mission teams found that the capsule’s heat shield had returned with concerning pockmarks and cracking. A heat shield is a crucial piece of hardware designed to protect a spacecraft and its astronauts from extreme temperatures as they’re descending back to Earth.

NASA's Orion capsule is drawn to the well deck of the USS Portland after splashdown following the Artemis I moon mission in December 2022 in the Pacific Ocean off the coast of Baja California, Mexico. - Mario Tama/Getty Images

The Artemis I Orion spacecraft still returned home safely and in one piece, but the damage raised questions about how well engineers understood the material used to create this hardware, called Avcoat, and how it behaves during the dangerous and dynamic final phase of flight.

If the heat shield becomes damaged or cracks in a particular way, it could lead to catastrophic failure. And there is no escape mechanism that could save the astronauts during this point in the journey. If the heat shield fails, the mission and crew would be lost.

The Artemis II Orion spacecraft has a heat shield that’s nearly identical to the one that flew on Artemis I. And NASA officials have acknowledged that it is less than ideal. But the agency maintains that it can bring the astronauts — NASA’s Reid Wiseman, Victor Glover and Christina Koch and Canadian Space Agency astronaut Jeremy Hansen — home safely, due to some changes made to the mission’s reentry strategy.

Mission managers say they are confident they have done their homework and understand the heat shield’s limitations and how to protect the crew, said Amit Kshatriya, NASA’s associate administrator, during a Thursday news briefing. And “the crew is going to put their lives behind that confidence,” he said.

But he acknowledged the stakes are high.

“The Orion spacecraft will enter the Earth’s atmosphere at approximately 25,000 miles per hour. That heat shield … will bear the full force of that reentry,” he said. “Every system we’ve demonstrated over the past nine days — life support, navigation, propulsion, communications — all of it depends on the final minutes of flight.”

NASA's Orion capsule splashes down in the Pacific Ocean in December 2022 after the uncrewed Artemis I moon mission. - Caroline Brehman/Pool/Getty ImagesArtemis I’s heat shield problem

The issues seen on Artemis I prompted more than a year of investigations, analysis and ground tests as NASA tried to understand the heat shield’s unexpected behavior.

Crucially, however, by the time Artemis I came back, the heat shield was already installed on the Artemis II capsule. That meant it was too late to alter the structure or design of the heat shield for this astronaut flight.

To address the problem, NASA has opted to put the Artemis II capsule and astronauts on a different trajectory than Artemis I took for its return home.

While the 2022 test flight used a “skip” reentry in which the capsule briefly plunged into the atmosphere before raising its altitude again and making a second plunge — this trip will attempt more of a “loft,” according to NASA Flight Director Rick Henfling.

The altered path is meant to create more favorable heating conditions, in the hopes that it will limit — but not eliminate — cracking on the heat shield.

The investigation process has given experts across NASA confidence that, even if the heat shield does not perform optimally, the astronauts will get home safe.

Howard Hu, NASA’s Orion program manager, repeated that sentiment in a prelaunch interview in late March. He also confirmed that the space agency will begin evaluating the Artemis II heat shield’s performance immediately upon return.

Advertisement

Following Orion’s expected splashdown off the coast of San Diego, as the astronauts are airlifted to a recovery vessel, a diver will plunge into the ocean to photograph the heat shield from below — providing mission managers some of the first evidence of how it performed.

“This is a deviant heat shield,” Dr. Danny Olivas, a former NASA astronaut who served on a space agency-appointed independent review team that investigated the incident, told CNN in January. “There’s no doubt about it: This is not the heat shield that NASA would want to give its astronauts.”

Still, Olivas said he believes NASA “has its arms around the problem” after conducting an in-depth investigation.

A vocal opponent

NASA’s decision-making has elicited criticism.

Dr. Charlie Camarda — a heat shield expert, research scientist and former NASA astronaut who was also a member of the first Space Shuttle crew to launch after the 2003 Columbia disaster — is among a group of former NASA employees who do not believe that the space agency should have put humans on board the Artemis II lunar excursion.

He was invited to a meeting at NASA’s headquarters in January to discuss the issue and review data from the agency’s investigations. Camarda said he walked away unconvinced the agency understood how the cracks in the heat shield could grow or cause a failure in flight.

“The fact that we decided to fly crew on a vehicle with a known defective heatshield is irresponsible, and I am certain no Apollo researcher would have allowed such a decision,” Camarda told CNN. “NASA has refused to attempt to develop an analytical solution which could help validate all ablative heat shield failure mechanisms.”

During a conversation in late March, Camarda said that he and several other likeminded ex-NASA workers sent letters expressing their concerns to safety officials. The cosigners included Dan Rasky, an expert on advanced entry systems and thermal protection materials who worked at NASA for more than 30 years, and Edgar Zapata, a retired Kennedy Space Center engineer who still serves on the NASA Innovative Advanced Concepts (NIAC) External Council.

A safety official responded, saying the committee — called the Aerospace Safety Advisory Panel or ASAP — would “keep your concerns in mind.”

NASA has repeatedly emphasized that safety is its top priority.

In a statement to CNN in January, NASA said the agency “considered all aspects” when making its decisions regarding the Artemis II heat shield, noting there is also “uncertainty that comes with the development and qualification of the processes of changing the manufacturing process.”

The Artemis II crew (clockwise from left), Mission Specialist Christina Koch, Mission Specialist Jeremy Hansen, Commander Reid Wiseman and Pilot Victor Glover, takes time out for a group hug inside the Orion spacecraft on the way home on Tuesday. - NASA

Top Artemis II officials as well as the astronauts have said they are confident that NASA understands the issue and the capsule will return home safely.

“The investigators discovered the root cause, which was the key” to understanding and solving the heat shield issue, Wiseman told reporters last July. “If we stick to the new reentry path that NASA has planned, then this heat shield will be safe to fly.”

Olivas, the former astronaut who was involved in the investigation, also noted that there is “no flight that ever takes off where you don’t have a lingering doubt.”

“But NASA really does understand what they have,” Olivas said. “They know the importance of the heat shield to crew safety, and I do believe that they’ve done the job.”

Debbie Korth, NASA’s Orion deputy program manager, reiterated during a Wednesday news conference that the testing the agency did after Artemis I gave her confidence in the plan to bring the Artemis II astronauts home.

“We understand how the rest of the vehicle behaves and have done an extensive ground test program to understand how this heat shield behaves,” Korth said.

She said that NASA plans to fly the modified reentry path only for this mission. On future flights, including Artemis III, the Orion capsule will include heat shield materials, designed to be more permeable, that hopefully will prevent the cracking issue.

NASA’s Artemis program is sending humans into deep space for the first time in more than five decades. Sign up for Countdown newsletter and get updates from CNN Science on out-of-this-world expeditions as they unfold.

For more CNN news and newsletters create an account at CNN.com

Original Article on Source

Source: “AOL Breaking”