Just five hours after a Russian Soyuz capsule brought three space station flyers back to Earth in Kazakhstan, SpaceX test fired the first stage engines of a Falcon 9 rocket in Florida early Saturday to clear the way for Thursday's planned launch of another four station-bound astronauts.
The Falcon 9, carrying a Crew Dragon commercial astronaut ferry ship, was hauled atop the historic 39A launch pad on Friday, a few hours before the rocket's three-man, one-woman crew arrived at the Kennedy Space Center to begin final launch preparations.
Following the same timeline that will be in place Thursday, SpaceX engineers loaded the booster with supercold liquid oxygen and RP-1 kerosene rocket fuel and briefly fired up nine first stage Merlin engines at 6:11 a.m. EDT. The "static fire" test is intended to validate prelaunch procedures and verify the readiness of the rocket.
Commander Shane Kimbrough, Megan McArthur, European Space Agency astronaut Thomas Pesquet and Japanese flier Akihiko Hoshide plan to don their futuristic SpaceX pressure suits and strap in Sunday morning for a pre-dawn dress rehearsal that will end with a simulated launch.
All four "Crew-2" astronauts are space veterans, but launching aboard a Crew Dragon will be a new experience.
"In the next few days, we have a little bit of training to do," Kimbrough said. "We're obviously well trained and ready to go, but we'll refresh a few things. And then our families and guests will start showing up. So that's an exciting time. We'll get to spend at least parts of the last few days with them before we go."
If all goes well, the crew will strap in for real Thursday, blasting off at 6:11 a.m. when Earth's rotation carries the launch pad into the plane of the space station's orbit. That will set up a 29-hour rendezvous and an automated docking at the lab's forward port around 5:30 a.m. Friday.
"We're looking forward to riding on the Crew Dragon, it's a brand new spacecraft and it looks fabulous," said Hoshide who, like Kimbrough, has flown aboard both the space shuttle and the Soyuz. "We're looking forward to the rumble and the sensation, all the G's pushing on our chests. It's going to be a lot of fun."
The launch will be the third piloted flight to orbit from U.S. soil since the space shuttle's final launch in 2011 and NASA's first using a previously flown SpaceX first stage and crew capsule.
The booster helped launch four Crew Dragon astronauts to the station last November and the capsule carried Douglas Hurley and Robert Behnken, McArthur's husband, to the lab last May. She will be strapped into the same seat her husband used for blastoff Thursday.
Shortly after arriving at the spaceport Friday, the crew visited the pad to see their rocket and spacecraft. After going through its previous re-entry, the first stage is somewhat sooty with the effects of atmospheric heating. The crew took advantage of that to start what may become a new pre-flight tradition.
"Since we're flying reused boosters, they're kind of darkened by the previous re-entry," Pesquet said. "So we were lucky enough to kind of ... draw our initials in this soot on the side of the booster. I don't know if this is going to stick, but I found it really cool."
Another tradition: bringing favorite foods to the space station to share with crewmates.
"I had some national pressure to bring some good stuff, and also from my crewmates," Pesquet said. "They were like, okay, we're flying with a Frenchman, it better be good. ... I don't want to spoil their surprise too much, but it's like two complete meals. I hope to have enough to share on some special occasions."
Hoshide added, "Unfortunately, we don't have any sushi, but we do have some new Japanese food as well. ... So looking forward to that and sharing it with my crewmates."
Kimbrough said he pretty much went with NASA's standard space menu, "so I'm going to rely on Aki and Thomas to come through with a little variety for us up there! But the NASA food is actually really great (and) we get to share with our Russians as well. So we'll have a lot of different cuisines up there."
The Soyuz MS-17/63Sin Kazakhstan early Saturday brought Sergey Ryzhikov, Sergey Kud-Sverchkov and NASA's Kate Rubins back to Earth after a 185-day stay aboard the station. They were replaced by Soyuz MS-18/64S commander Oleg Novitskiy, Pyotr Dubrov and NASA astronaut Mark Vande Hei, who were launched to the lab on April 9.
Kimbrough and his fellow Crew-2 astronauts, in turn, will replace Crew-1 commander Michael Hopkins, Victor Glover, Shannon Walker and Japanese astronaut Soichi Noguchi, who were launched last November in SpaceX's first operational Crew Dragon flight. The Crew-1 astronauts plan to return to Earth April 28.