The NASA astronauts who will fly SpaceX's Crew Dragon's first human test flight opened up regarding the risks involved in the mission. They also discussed the rating that calculates the probability of losing a crew member during the test flight.

Crew Dragon's Demo-2 mission will serve as the first time that American astronauts will launch from U.S. soil in about a decade. For this mission, NASA's Doug Hurley and Bon Behnken were selected to fly the Crew Dragon capsule for its first human flight to the International Space Station (ISS).

Bob Behnken and Doug Hurley
NASA astronauts Robert Behnken, left, and Douglas Hurley listen as NASA Administrator Jim Bridenstine gives remarks after the crew arrived at the Launch and Landing Facility at NASA’s Kennedy Space Center ahead of SpaceX’s Demo-2 mission, Wednesday, May 20, 2020, in Florida. NASA/Bill Ingalls

Demo-2's Loss-Of-Crew Probability

During the planning stage of the mission, NASA established a set of safety requirements that SpaceX needed to meet in order to proceed with the launch. One of these is the Loss-of-crew figure, which calculated the probability of the death or permanent disability of one or more crew members of a spacecraft during a mission. For Demo-2, the loss-of-crew requirement is 1-in-270, which SpaceX exceeded by achieving 1-in-276 after implementing various safety features and procedures for the mission.

Although the loss-of-crew probability plays a huge role in assessing the risk involved in launches, Hurley noted that there are also other factors that can determine the success or failure of a mission to space. "Those numbers are certainly part of the equation when you assess risk, but they're certainly not exclusive by any stretch of the imagination," the astronaut said, according to Space News. "They're certainly a factor, but there's just so much more to assessing risk, and all the things that you put into the decision matrix before you go fly."

Accepting Demo-2's Risks

Both Hurley and Behnken are aware that there are a lot of risks involved in SpaceX's Demo-2 mission, especially since it will be the company's first human commercial flight to space. After years of working with NASA and SpaceX, the astronauts noted that they have learned to accept the risks that come with conducting spaceflights.

"We've had the luxury over the last five-plus years to be deeply embedded and understand the trades that were made," Behnken stated. "I think we're really comfortable with it and we think that those trades have been made appropriately. As far as insight goes, we've probably had more than any crew has in recent history."

Falcon 9
Satellite image of Falcon 9 Maxar

Demo-2's New Launch Schedule

The Demo-2 mission was supposed to launch on May 27. Unfortunately, due to weather concerns, the launch was canceled and rescheduled. SpaceX and NASA have agreed to launch the mission on Saturday (May 30) at 3:22 p.m. EDT.