Artemis II capsule's heat shield may fail, with no Plan B from NASA

The National Aeronautics and Space Administration (NASA) Artemis II crew is set to splash down today after spending 10 days in space.

The space agency has warned that there exists no plan B in case the heat shield of the capsule fails during reentry.

The mission is relying on only a single thermal protection, a 3-inch-thick heat shield, to protect itself from the extreme heat, estimated to be around 2,760°C, of the Earth’s atmosphere.

In a press conference on Tuesday, NASA Administrator Jared Isaacman said: “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 added, “There's no plan B there. That is the thermal protection system. The heat shield has to work.”

Despite previous successful missions, the concerns regarding the heat shield are not unfounded as the uncrewed Artemis I mission in 2022 faced an unexpected erosion in parts of its heat shield.

Engineers have implemented several changes in the Orion spacecraft’s thermal protection system to make sure the issue does not occur; however, the NASA administrator’s statement has raised concerns.

The crew capsule will separate from the rocket at around 76 miles above the Earth’s atmosphere. 

The capsule's speed is expected to reach around 25,000 miles per hour, violently compressing the air outside, causing the temperature to rise nearly 5,000°F.

The 4-member crew is expected to splash down off the coast of San Diego, California, at 8:07 p.m. ET.