NASA assessed 1-in-276 odds for loss of crew on the first flight of astronauts aboard SpaceX’s Crew Dragon in 2020. For Boeing’s Starliner in 2024, the probability was 1 in 295. You wouldn’t be wrong to question those numbers given the proven performance of Dragon and Starliner.

So, what do the Artemis II astronauts make of all this?

The mission’s commander, Reid Wiseman, said the crew members were trying to prepare their families “honestly and openly” for the hazards of a circumlunar flight.

“I went on a walk with my kids, and I told them, ‘Here’s where the will is, here’s where the trust documents are, and if anything happens to me, here’s what’s going to happen to you,’” Wiseman said. “That is a part of this life. I actually wish more people in everyday life talked to their families that way because you never know what the next day is going to bring.”

Any sailor knows you can’t stay in the harbor forever. Test pilots and astronauts take calculated risks for a living.

“When you see numbers like Mach 39 at entry, when you see numbers like 38,000 miles, 250,000 miles, and 5 or 6 million pounds on the pad, those are just insane numbers,” Wiseman said. “These numbers, you don’t even comprehend. There’s risk in that. We don’t know what we don’t know right now, so we’ll go learn all that [on the mission].

Despite the unknowns, Wiseman is ready: “For me, I actually feel completely 100 percent bought in. When I get into Orion, it’s like climbing into my bed, and I’ll feel warm and tucked in.”

The formal risk matrix for Artemis II is similar to that of Artemis I, with MMOD again at the top of the list. Matt Ramsey, NASA’s Artemis II mission manager, told Ars in January that the Orion spacecraft’s environmental control and life support system, which didn’t fly with its full capability on Artemis I, is the second-highest risk for Artemis II. “Those two are my biggest worries,” said Ramsey, who has been with NASA since 2002.