NASA has approved SpaceX's plan to load propellants on a rocket while the astronauts are already strapped into the spacecraft, according to . SpaceX has used the tactic, known as "load-and-go," for dozens of satellite launches, but previously it was unclear if NASA would approve the company's fueling procedure with humans aboard.
It's standard procedure for SpaceX to fuel their Falcon 9 rocket with RP-1 kerosene rocket fuel and liquid oxygen in the final hour before launch, lifting off shortly after the tanks are filled. "Load-and-go," however, is viewed by some in the space industry as an unnecessary risk.
These propellants are kept at extremely cold temperatures, allowing them to shrink in volume so that more fuel can be packed into the Falcon 9. More fuel means more lifting capability, but super-chilled liquid oxygen warms quickly, within half an hour, so the oxidizer must be loaded immediately before launch.
“We never could get comfortable with the safety risks that you would take with that approach," John Mulholland, who oversees Boeing's Commercial Crew Program, the Washington Post in May. "When you’re loading densified propellants, it is not an inherently stable situation.”
SpaceX has, of course, pulled off many successful load-and go launches. But an anomaly on September 1, 2016 during propellant loading resulted in a Falcon 9 explosion during the run-up to an engine test fire. That incident two years ago resulted in some reservations regarding SpaceX's load-and-go procedure.
Risk is an inherent part of space travel, and many pro-load-and-goers argue that SpaceX's track record speaks for itself. Since the 2016 explosion, SpaceX has pulled off 33 straight successful launches. The company has saved NASA hundreds of millions of dollars with its many launches to the International Space Station. But those missions have all been uncrewed.
As SpaceX prepares to launch its first crewed flights, NASA has given the green light for load-and-go for astronaut missions.
"Our teams have been following along with their normal operations, so we have a pretty good understanding of how their vehicle operates,” Kathy Lueders, NASA’s commercial crew program manager, said in an . "That also really helped us in the assessment because we really understand now why SpaceX was doing what they’re doing."