Artemis II splashdown: How NASA fixed Orion's heat shield issue
What's the story
The final 13 minutes of NASA's historic 10-day Moon mission, Artemis II, were crucial for the four astronauts on board. The return to Earth was a test of the Orion spacecraft's heat shield. "It's 13 minutes of things that have to go right," said Artemis II flight director Jeff Radigan at a news briefing on Thursday.
Heat shield failure
NASA reworked Artemis II's descent trajectory to protect crew
Before leaving Kennedy Space Center on April 1, NASA was aware of a problem with the Orion spacecraft, dubbed Integrity by its crew. During its 2022 test flight, Orion experienced unexpected heating and stress during re-entry. Over 100 cracks and chips were found on the heat shield after re-entry, prompting engineers to change Artemis II's descent trajectory to minimize heating and protect both capsule and crew.
Successful re-entry
Orion survived extreme re-entry forces from lunar-return trajectory
The crew's return marked a major milestone for the Lockheed Martin-built Orion spacecraft, as it demonstrated its ability to endure extreme re-entry forces from a lunar-return trajectory. This came after a nerve-wracking 13-minute fiery descent through Earth's atmosphere that generated frictional heat, raising temperatures on the capsule's exterior to nearly 5,000°F (2,760°C).
Communication loss
Re-entry stress peak cut off radio communications with crew
At the peak of re-entry stress, intense heat and air compression created a superheated plasma sheath around the capsule, cutting off radio communications with the crew for several minutes. The tension was relieved when contact was re-established and two sets of parachutes were seen deploying from the nose of the free-falling capsule. This slowed its descent to about 25km/h before Orion gently splashed down in Earth's ocean.
Strategic approach
NASA flew Artemis II with flawed design
Interestingly, Artemis II had an even less permeable shield than its predecessor, Artemis I. However, NASA discovered that it was all about the right angle. Instead of delaying the mission by over a year to install a reworked heat shield, they flew Artemis II with the same flawed design but changed how the capsule returned. This involved applying more heat consistently during descent to prevent gas from getting trapped under an outer char layer.