Artemis II Reentry Risks Heat Shield Concerns

As the four astronauts of NASA's Artemis II mission hurtle toward Earth after a historic lunar flyby, they face what officials describe as the most perilous phase of their journey: reentry through the atmosphere, where a heat shield previously damaged in testing must protect them from temperatures nearing 5,000 degrees Fahrenheit.

The crew, consisting of NASA astronauts Reid Wiseman, Victor Glover, and Christina Koch, along with Canadian Space Agency astronaut Jeremy Hansen, completed a six-hour loop around the Moon's far side earlier this week, setting a new record for human distance from Earth at 252,756 miles. Their spacecraft, Orion, now races back at speeds up to 25,000 miles per hour, set to splash down in the Pacific Ocean off San Diego at 8:07 p.m. ET on Friday. During reentry, Orion will plunge into the thermosphere, enveloped in a superheated plasma sheath that will briefly sever communications with mission control for several minutes.

The mission's success hinges on Orion's thermal protection system, a 7.5-centimeter-thick layer of Avcoat material designed to ablate and dissipate heat through friction. This system drew scrutiny after the uncrewed Artemis I flight in...