President Donald Trump and Vice President Mike Pence are expected at Kennedy for the planned 4:33 p.m. liftoff, but “our highest priority” will remain the astronauts' safety, according to Bridenstine.
Bridenstine said he texted the two astronauts Monday and told them, “`If you want me to stop this thing for any reason, say so. I will stop it in a heartbeat if you want me to.' They both came back and they said, ‘We’re go for launch.' ”
Hans Koenigsmann, a SpaceX vice president, said Monday evening that he and other company workers have imagined themselves in the astronauts' shoes on launch day — “or their helmets.”
“That changes the equation pretty dramatically," he said.
SpaceX has been launching cargo capsules to the space station since 2012.
NASA astronauts go back to the future with capsule launch
“It's a huge step, obviously, going from cargo ... to launching two people that are dads as we call them and have families, kids, wives.," Koenigsmann added.
NASA will have input throughout the countdown, but in the end, it will be SpaceX giving the final go — with NASA's concurrence.
“SpaceX is controlling the vehicle, there’s no fluff about that,” Norm Knight, a NASA flight operations manager, said Monday.
The odds of acceptable launch weather improved Tuesday to 60%. But that didn't factor in conditions along the Dragon’s route to orbit.
SpaceX needs relatively calm waves and wind up the U.S. and Canadian seaboard and across the North Atlantic to Ireland, in case astronauts Hurley and Behnken need to make an emergency splashdown.
If SpaceX does not launch during Wednesday's split-second window, the next try would be Saturday. Liftoff is set for 4:33 p.m. EDT.
The last time astronauts launched from Florida was on NASA's final space shuttle flight in July 2011. Hurley was the pilot of that mission.
NASA hired SpaceX and Boeing in 2014 to transport astronauts to the space station, after commercial cargo shipments had taken off. Development of SpaceX's Dragon and Boeing's Starliner capsules took longer than expected, however, and the U.S. has been paying Russia to launch NASA astronauts in the interim.