Artemis astronauts face the most dangerous part of their mission, ‘riding a fireball through the atmosphere’ on re-entry

The four crew members of Artemis 2 face the most dangerous remaining part of their mission on April 10. The Orion spacecraft, which has traveled to the far side of the Moon, is scheduled to return to Earth at 5.07 p.m. PDT (8.07 p.m. EST). The descent will last just 13 minutes, during which the exterior of the spacecraft will reach temperatures exceeding 2,700 degrees Celsius due to the extreme pressure and air resistance. If all goes well, Commander Reid Wiseman, pilot Victor Glover, and mission specialists Christina Koch and Jeremy Hansen will splash down in the Pacific Ocean near the coast of San Diego, California, where a U.S. Navy amphibious assault ship is already waiting.

Along with liftoff, the return to Earth is the most dangerous part of a mission like Artemis 2, during which controllers will have their “hearts in their mouths,” in the words of mission engineer Eduardo García Llama. The capsule will re-enter Earth’s atmosphere at speeds of up to 25,000 miles per hour. It is essential that the spacecraft enters at the correct angle of inclination to avoid burning up, even though the exterior will be ablaze.

“Riding a fireball through the atmosphere is profound,” Glover said at a press conference from space. The 49-year-old U.S. Navy officer, test pilot, and astronaut says he’s been thinking about the moment of splashdown in the Pacific since April 2023, when he was selected for the Artemis 2 mission.

All eyes will be on the heat shield that protects the Orion spacecraft and its crew from the extremely high temperatures that will be reached during atmospheric reentry. About 40 minutes before falling to Earth, it will detach from the European Service Module. This component, built by European companies, has been essential to the mission, providing air, water, climate control, and propulsion for the journey from Earth to the Moon and back.

After undocking, the spacecraft will rotate so that the rear section, where the heat shield is located, is at the front. This shield is made of heat-absorbing materials that protect the spacecraft from high temperatures. The entire landing is automated, and the astronauts experience it seated facing away from the direction of travel.

During the uncrewed test flight of Artemis 1 in 2022, serious damage was detected in the heat shield. NASA astronaut Charles Camarda, 73, has been one of the most vocal critics on this issue, even warning that Artemis 2 should not be launched with a crew on board. He believes NASA is exposing itself to problems similar to those that caused the Columbia shuttle disaster in 2003, in which seven astronauts died, and which was due to failures in the heat shield.

NASA has been analyzing the problem and has decided to alter the spacecraft’s entry angle. These changes, along with a reanalysis of the tiles that make up the heat shield, are sufficient to ensure the crew’s safety, Debbie Korth, one of the top officials for the Orion capsule, explained to this newspaper during an interview at NASA’s Kennedy Space Center.

“It will all start fast and end even faster,” explained engineer Rick Henfling at a press conference. The “fun” will begin when the spacecraft is about 120 kilometers (75 miles) high and begins to re-enter the upper atmosphere. By then, the service module, a technological marvel costing around $25 million, will already be disintegrating far from the spacecraft. Twenty-four seconds after re-entry, Orion will be surrounded by plasma, a brilliant fourth state of matter that arises when the air is ionized by the intense compression and friction exerted by the spacecraft. At this moment, all communication with Earth will be lost. The blackout will last six long minutes, until the spacecraft is about 45 kilometers (28 miles) above the sea. At about six kilometers (3.7 miles), the first parachutes will deploy, reducing the speed to about 300 kilometers per hour (186 mph), and then the three main parachutes will be deployed. If all goes well, Orion will touch down at about 30 kilometers per hour (18.6 mph).

NASA is considering different trajectories in case of an emergency, which would change the final landing point, placing it farther from the coast. If the splashdown goes as planned, the astronauts will withstand pressures about 3.9 times greater than Earth’s gravity, although in case of unforeseen circumstances, these pressures could increase to seven times or even more.

Once they land, a Navy diver will approach the spacecraft and open the hatch. Several doctors will enter to check on the crew members, who will then exit in a predetermined order: Koch, Glover, Hansen, and finally Commander Wiseman. Several helicopters will transport them to the USS John P. Murtha. From there, the astronauts may be flown to dry land, explained Liliana Villarreal, the rescue officer in charge. Up to seven aircraft will be involved in the rescue, and there is the possibility of activating additional teams from Pearl Harbor, Hawaii, should Orion not land at the designated point.

Hours before all this, the four crew members of Artemis 2 held a press conference from space, in which they reviewed a record-breaking mission. The astronauts have become the humans who have traveled farthest in space, and they also observed areas of the far side of the Moon for the first time. Koch, Glover, and Hansen are the first woman, the first Black person, and the first Canadian, respectively, to travel to the Moon.

“There’s so much data that you’ve seen already, but all the good stuff is coming back with us. There are so many more pictures, so many more stories,” Glover said.

Commander Wiseman explained that everyone was able to speak briefly with their families, although he was only able to cry when he connected with his two daughters. One of the most emotional moments of the mission was when Wiseman requested that a new lunar crater be named after his wife, Anne Carroll Taylor Wiseman, who died of cancer in 2020 at the age of 46. “I’m actually getting chills right now just thinking about it. My palms are sweating,” Wiseman said of his impressions during the lunar flyby. “It is amazing to watch your home planet disappear behind the Moon. You could actually see the terrain in the Moon projected across the Earth, as the Earth was eclipsing behind the Moon. It was just an unbelievable sight. And then it was gone. It was out of sight.”

Koch, a 47-year-old physicist and engineer, the only non-military member of the mission, humorously described what it’s been like living in a five-meter-diameter capsule. The spacecraft seems “bigger in microgravity, and we’re bumping into each other 100% of the time.” “Looking out the window, taking pictures, and eating... everything we do in here is a four-person activity,” she added.

The astronaut explained that the four crew members of Artemis 2 are carrying a baton, similar to those used by relay athletes, to pass to the next crew. Artemis 3 is scheduled to launch in 2027 to test the lunar landers in Earth orbit. A year later, the lunar landing with Artemis 4 is expected.

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