After nearly 10 days in space, a record-setting trip beyond the moon, and a long arc back toward home, NASA’s four-person crew is preparing for the most dangerous part of the mission: plunging back through Earth’s atmosphere. 

The reentry sequence is slated for Friday evening and is expected to unfold over several hours, testing both the Orion spacecraft’s heat shield and the crew’s endurance as they transition from deep space to a high-speed descent toward the Pacific Ocean.