New Delhi, April 11 -- The last 13 minutes of the historic 10-day NASA moon mission, the journey back to Earth, were the most critical for the four astronauts - Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen - aboard the Artemis II flight. It was a test of the Orion spacecraft's heat shield.

"It's 13 minutes of things that have to go right," Artemis II flight director Jeff Radigan said at a news briefing on Thursday.

Why?

NASA knew there was a problem with the Orion spacecraft, which the crew named Integrity, even before it left the Kennedy Space Center launchpad on April 1.

Orion had sustained an unexpected level of scorching and stress on re-entry during its 2022 test flight. Engineers had discovered over 100 locatio...