Preparations for Thursday’s scheduled launch of a SpaceX Dragon capsule with a four-man crew to the International Space Station delivered a new readiness check at NASA’s Kennedy Space Center in Florida on Tuesday, but officials are monitoring marginal wind and sea conditions in remote break-off zones in the Atlantic Ocean which could force a launch delay.
With no significant technical issues hampering launch on Thursday, NASA and SpaceX officials gave a “go” to continue flight preparations at the end of a Launch Readiness Review early Tuesday.
The launch of the Crew Dragon Endeavor spacecraft atop a SpaceX Falcon 9 rocket is scheduled for 6:11:35 a.m. EDT (1011: 35 GMT) Thursday from pad 39A at NASA’s Kennedy Space Center.
It is the first time astronauts have been launched on a Falcon 9 rocket powered by a previously flown first-stage booster, and the first reuse of a Crew Dragon spacecraft. The mission, known as Crew-2, is the third SpaceX flight with astronauts overall.
The astronauts and NASA executives are familiar with SpaceX’s reuse plan. The company has successfully flown 57 missions using recycled Falcon boosters.
The Launch Readiness Review early Tuesday was the last major gathering to get the Crew-2 mission ready for launch on Thursday.
“Safety is number one in all these assessments, and that’s how it should be,” said Norm Knight, deputy director of flight operations at NASA’s Johnson Space Center in Houston. This manned space flight is brutal. It is the vigilance of the teams that ensures continued safety, and it was certainly present in these reviews this week. “
NASA executives have addressed a previous technical concern related to SpaceX’s loading of liquid oxygen propellant into the first stage of its Falcon 9 rocket.
SpaceX recently discovered during a ground test in Texas that it overfilled the oxidation tank with a super-cold liquid oxygen tank. A company official said last week that it appeared that SpaceX had loaded more liquid oxygen into the rocket during the Falcon 9’s flight history, which spans more than 100 missions since 2010.
Steve Stich, the program manager of NASA’s commercial crew, said an analysis showed that the Falcon 9 rocket can go well without changing SpaceX’s loading procedures.
“We concluded that the amount of liquid oxygen in the first stage was well within the guidance navigation and steering analysis and performance analysis family within the load and structural capacity of the vehicle,” Stitch said in a news conference on Tuesday.
Engineers have also shown that the Falcon 9 missile with the extra liquid oxygen on board can handle last-second abortions and other situations.
“So we continued with that amount of LOX (liquid oxygen) on the vehicle,” said Stich.
The only concern noted by officials on Tuesday was with the weather and sea conditions along the Falcon 9 missile’s flight corridor northeast of Cape Canaveral. Officials are monitoring the winds, sea conditions and lightning in the areas where the Crew Dragon capsule could crash in the event of an in-flight emergency.
The weather forecast for the Florida launch site is looking good, with an 80% chance of acceptable conditions ahead of Thursday’s launch. There is a 90% chance of good weather at the Kennedy Space Center for an opportunity to launch a backup on Friday at 5:49 a.m. EDT (0949 GMT).
The prediction for degraded zones in the Atlantic is “a bit tricker,” said Stich. Forecast models show that some areas along the Falcon 9’s flight path could have high winds later this week.
“Of the two days, right now, I’d say Friday looks a little bit better than Thursday,” said Stich. “We will keep looking at that again.”
According to the official forecast from the US Space Force’s 45th Weather Squadron, there is also a “moderate” risk that winds over the Florida launch site will exceed the limits of the Falcon 9 rocket Thursday morning.
NASA and SpaceX officials will meet again on Wednesday to reassess the weather forecast and decide when to make a final decision on whether or not to proceed with the launch countdown before the early morning, early Thursday.
Assuming a timely launch on Thursday, the Falcon 9 rocket will orbit the Crew Dragon Endeavor spacecraft approximately 12 minutes after launch. An automated array of thrusters will lead the capsule to dock with the space station Friday at 5:30 a.m. EDT (0930 GMT).
If the launch is delayed to Friday, docking would shift to Saturday.
NASA astronaut Shane Kimbrough, the commander of the Crew-2 spacecraft, said he and his crew will join the ride on the Dragon spacecraft if everything goes according to plan.
“The spacecraft is a futuristic spacecraft, and it can do just about anything,” he said at a news conference last month.
All four Crew-2 astronauts are veterans of previous space missions. Kimbrough and Japanese mission specialist Akihiko Hoshide have each flown both a space shuttle and a Russian Soyuz spacecraft. NASA pilot Megan McArthur and European Space Agency astronaut Thomas Pesquet have each flown one space shuttle and one Soyuz mission, respectively.
“The technology is very different (from the shuttle and the Soyuz),” said Kimbrough, a 53-year-old retired US Army colonel and Apache helicopter pilot. “We put touchscreens in your hand instead of a joystick in your hand to control the thing … Megan and I are trained to manually take over at each stage of the flight if necessary, but hopefully we’ll just be there for the ride and enjoy it. “
It will be the first visit to the space station for McArthur, 49, who was selected as an astronaut in 2000 and flew the space shuttle Atlantis in 2009 on the last service mission to the Hubble Space Telescope.
She compared her 13-day space shuttle flight to a business trip. Now she is moving to a new house.
McArthur’s husband, astronaut Bob Behnken, flew on the first mission of SpaceX’s Crew Dragon Endeavor capsule last year. She will occupy the same seat in the renovated and upgraded spaceship.
The Crew-2 astronauts will return to Earth in late October for a splashdown off the coast of Florida.
Hoshide will take over the commander of the space station’s Expedition 65 crew next week, taking over from NASA astronaut Shannon Walker. Walker and her crew – Mike Hopkins, Victor Glover and Japanese astronaut Soichi Noguchi – will return to Earth on April 28 with their Crew Dragon Resilience spacecraft to complete a mission that kicked off in November.
Later this year, Pesquet will get a turn as commander of the space station. He said the automation of SpaceX’s Crew Dragon spacecraft makes the vehicle safer.
“For us, it means we don’t have to take that many actions in a nominal situation,” said Pesquet, who was an instructor in cockpit protocols for Air France, and logged 196 days in orbit during his first space mission. “Of course we have to take action in a non-nominal situation. But what it means is that you are available to deal with the situation. Your situational awareness is just incredible.
“You have those huge, big screens that show you what’s going on in every way possible,” said Pesquet. “The priority of the information has already been pre-analyzed by the system. The color coding is great. The way the information is organized is simply fantastic. You always know what’s going on.
“Soyuz is incredibly reliable, but you had to understand all that information that was sparse and scattered in every corner of your control panel with digital meters and analog meters,” said Pesquet. “That’s why the training took so much longer. I love it. We’ll love it, and I think it makes the system more reliable overall. “
The Crew-2 astronauts will support more than 200 research experiments on the space station, take spacewalks to maintain and upgrade the more than 20-year-old complex, and help demonstrate new technologies for missions to the moon.
The arrival of the Crew-2 astronauts will temporarily increase the space station’s crew to 11 people, including three newly arrived residents who flew to the outpost in a Russian Soyuz spacecraft earlier this month. With the return of the Crew-1 astronauts on April 28, the space station’s workforce returns to the long-term level of seven crew members.
Email the author.
Follow Stephen Clark on Twitter: @ StephenClark1.