May 15, 2021

NASA, SpaceX watching weather in downrange abort zones for crew launch


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A SpaceX Falcon 9 rocket and Crew Dragon spacecraft stand on pad 39A at NASA’s Kennedy Space Center in Florida. Credit: NASA/Joel Kowsky

Preparations for the planned liftoff Thursday of a SpaceX Dragon capsule with a four-person crew to the International Space Station cleared another readiness review Tuesday at NASA’s Kennedy Space Center in Florida, but officials are tracking marginal wind and sea conditions in downrange abort zones in the Atlantic Ocean that could force a launch delay.

With no significant technical issues standing in the way of launch Thursday, NASA and SpaceX officials gave a “go” to continue flight preps at the conclusion of a Launch Readiness Review early Tuesday.

Liftoff of the Crew Dragon Endeavour spacecraft on top of a SpaceX Falcon 9 rocket is set for 6:11:35 a.m. EDT (1011:35 GMT) Thursday from pad 39A at NASA’s Kennedy Space Center.

It will be the first time astronauts have 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 managers are comfortable with SpaceX’s reuse plan. The company has successfully flown 57 missions using recycled Falcon boosters.

The Launch Readiness Review early Tuesday was the final major meeting to clear the Crew-2 mission for liftoff Thursday.

“Safety has been number one in all these reviews, and that’s the way it should be,” said Norm Knight, deputy director of flight operations at NASA’s Johnson Space Center in Houston. This business of human spaceflight is unforgiving. It’s the vigilance from the teams that guarantee that continued safety, and it was definitely present in these reviews this week.”

NASA managers cleared a prior technical concern associated with 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 was slightly over-filling the oxidizer tank with super-cold liquid oxygen tank. A company official said last week it appeared SpaceX had loaded more liquid oxygen into the rocket throughout the Falcon 9’s flight history, which includes more than 100 missions since 2010.

Steve Stich, NASA’s commercial crew program manager, said an analysis showed the Falcon 9 rocket is good to go without changing SpaceX’s loading procedures.

“We concluded the that amount of liquid oxygen on the first stage was well within family of the guidance navigation and control analysis, and performance analysis, within the loads and structural capability of the vehicle,” Stitch said in a press conference Tuesday.

Engineers also demonstrated the Falcon 9 rocket can handle last-second aborts and other situations with the extra liquid oxygen on-board.

“So we were going to proceed with that amount of LOX (liquid oxygen) on the vehicle,” Stich said.

The only concern noted by officials Tuesday was with weather and sea conditions along the Falcon 9 rocket’s flight corridor northeast of Cape Canaveral. Officials are monitoring winds, sea states, and lightning in the areas where the Crew Dragon capsule might splash down in the event of an in-flight emergency.

The weather forecast for the launch site in Florida looks good, with an 80% chance of acceptable conditions for liftoff Thursday. There’s a 90% chance of good weather at the Kennedy Space Center for a backup launch opportunity at 5:49 a.m. EDT (0949 GMT) Friday.

The forecast for abort zones in the Atlantic Ocean is a “little bit tricker,” Stich said. Forecast models show some areas along the Falcon 9’s flight path may have high winds later this week.

“Of the two days, right now, I would say Friday looks a little bit better than Thursday,” Stich said. “We’ll continue to watch that weather.”

This map illustrates the ground track for the Crew Dragon and Falcon 9 rocket heading northeast from the Kennedy Space Center in Florida. The red zone — called the Downrange Abort Exclusion Zone — in the North Atlantic Ocean is a region where the control teams want to avoid Ann abort due to cold water temperatures and rough seas. Credit: NASA

There is also a “moderate” risk that upper level winds over the Florida launch site might exceed the Falcon 9 rocket’s limits Thursday morning, according to the official outlook issued by the U.S. Space Force’s 45th Weather Squadron.

NASA and SpaceX officials will meet again Wednesday to reassess the weather forecast, and decide when to make a final decision on whether to proceed with the predawn launch countdown early Thursday.

Assuming an on-time launch Thursday, the Falcon 9 rocket will release the Crew Dragon Endeavour spacecraft in orbit about 12 minutes after liftoff. An automated series of thruster firings will guide the capsule to a docking with the space station at 5:30 a.m. EDT (0930 GMT) Friday.

If the launch is delayed to Friday, docking would slip to Saturday.

NASA astronaut Shane Kimbrough, the Crew-2 spacecraft commander, said he and his crewmates will be along for the ride on the Dragon spacecraft if all goes according to plan.

“The spacecraft is a futuristic spacecraft, and it pretty much can do it all,” he said in a press conference last month.

All four Crew-2 astronauts are veterans of prior space missions. Kimbrough and Japanese mission specialist Akihiko Hoshide have each flown on both a space shuttle and a Russian Soyuz spacecraft. NASA pilot Megan McArthur and European Space Agency astronaut Thomas Pesquet have each flown on one space shuttle and one Soyuz mission, respectively.

“The technology is much different (than the shuttle and Soyuz),” said Kimbrough, a 53-year-old retired U.S. Army colonel and Apache helicopter pilot. “We’re doing touchscreens instead of a joystick in your hand to fly the thing … Megan and I are trained to take over manually during any phase of the flight if need be, but hopefully, we’ll just be along for the ride and get to 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 on the space shuttle Atlantis on the final servicing mission to the Hubble Space Telescope in 2009.

She likened the her 13-day flight on the space shuttle to a business trip. Now she’s actually moving to a new home.

McArthur’s husband, astronaut Bob Behnken, flew on the first mission of SpaceX’s Crew Dragon Endeavour capsule last year. She will occupy the same seat in the refurbished and upgraded spaceship.

The Crew-2 astronauts are scheduled to return to Earth for a splashdown off the coast of Florida in late October.

Hoshide will take over as commander of the space station’s Expedition 65 crew next week, assuming the helm from NASA astronaut Shannon Walker. Walker and her crewmates — Mike Hopkins, Victor Glover, and Japanese astronaut Soichi Noguchi — are scheduled to come back to Earth on April 28 on their Crew Dragon Resilience spacecraft, wrapping up a mission that launched in November.

The Crew-2 astronauts speak with reporters Friday at the Kennedy Space Center in Florida. Credit: Stephen Clark/Spaceflight Now

Later this year, Pesquet will get a turn as space station commander. He said the automation of SpaceX’s Crew Dragon spacecraft makes the vehicle safer.

“For us, what it means is we don’t have that many actions to take in a nominal situation,” said Pesquet, who was an instructor in cockpit protocols for Air France, and logged 196 days in orbit on his first space mission. “Of course, in an off-nominal situation, we have to take action. But what it means is you’re available to manage the situation. Your situational awareness is just unbelievable.

“You have these huge big screens that are showing you, in every possible way, what’s happening,” Pesquet said. “The priority of the information is already pre-analyzed by the system. The color coding is great. The way the information is laid out is just fantastic. You know all the time what’s going on.

“Soyuz is unbelievably reliable, but you had to make sense of all that information that was sparse and disseminated at every corner of your control panel, with digital gauges and analog gauges,” Pesquet said. “That’s why the training was so much longer. I think it’s great. We will 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, perform 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 raise the space station’s crew size to 11 people, including three newly-arrived residents who flew to the outpost on a Russian Soyuz spacecraft earlier this month. With the return of the Crew-1 astronauts April 28, the staffing of the space station will return to its long-term level of seven crew members.

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Follow Stephen Clark on Twitter: @StephenClark1.


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