NASA and SpaceX pre­pare for a splash­down re­turn to Earth

The Washington Post Sunday - - FRONT PAGE - BY CHRIS­TIAN DAVENPORT chris­tian.davenport@wash­post.com

The launch two months ago went about as smoothly as pos­si­ble, fly­ing Amer­i­can as­tro­nauts into orbit from U.S. soil for the first time since 2011. And SpaceX’s Dragon space­craft docked so grace­fully with the In­ter­na­tional Space Sta­tion that NASA as­tro­nauts Bob Behnken and Doug Hur­ley didn’t even feel it. Now they are com­ing home. Even though Hur­ri­cane Isa­ias is pro­jected to hit the east coast of Florida just as Dragon would be re­turn­ing, NASA and SpaceX, which owns and op­er­ates the space­craft, pro­ceeded with a land­ing at­tempt, aim­ing for a site in the Gulf of Mex­ico near Pen­sacola along the Florida Pan­han­dle, where waves are ex­pected to be one to two feet.

“Not in­tu­itive, but Isa­ias may ac­tu­ally help make nice weather on land­ing a few hun­dred miles west,” Ze­bu­lon Scov­ille, NASA’s flight di­rec­tor, wrote on Twit­ter on Satur­day morn­ing.

It will be the first land­ing ever by as­tro­nauts in the gulf, ac­cord­ing to Jonathan McDow­ell, as­tronomer at the Har­vard-Smith­so­nian Cen­ter for As­tro­physics.

The crew un­docked from the sta­tion at 7:35 p.m. East­ern time Satur­day, fir­ing small nose rock­ets to push away. Splash­down on Sun­day is sched­uled for 2:42 p.m.

Even with­out weather con­cerns, the re­turn jour­ney is a treach­er­ous one. The space­craft will have to with­stand tem­per­a­tures as high as 3,500 de­grees as it moves through the at­mos­phere. A quar­tet of para­chutes will have to slow the 21,200pound cap­sule for a soft land­ing at sea. Then res­cue crews will have to quickly re­cover the ve­hi­cle from the gulf in what would be the first wa­ter land­ing for Amer­i­can as­tro­nauts since a joint U.S.-Soviet mis­sion in 1975.

If all that weren’t chal­leng­ing enough, NASA and SpaceX are at­tempt­ing to bring the crew home dur­ing an ac­tive hur­ri­cane sea­son. And the pos­si­bil­ity of strong winds from Isa­ias kick­ing up an un­ruly churn has put NASA and SpaceX of­fi­cials on alert.

But if SpaceX is able to bring Hur­ley and Behnken home safely in the first test flight with hu­mans on board, it would be the tri­umphant cul­mi­na­tion of years of work and the open­ing of a new era in hu­man space­flight in which cor­po­ra­tions play a star­ring role along­side NASA.

Last year, SpaceX suc­cess­fully com­pleted a test run of the mis­sion with­out as­tro­nauts that went smoothly and paved the way for Hur­ley and Behnken’s mis­sion. It has also flown its cargo Dragon space­craft back to Earth in wa­ter land­ings many times suc­cess­fully, so it has lots of prac­tice.

Still, no one is ready to cel­e­brate un­til the men are back safely.

“The hard­est part was get­ting us launched, but the most im­por­tant part is bring­ing us home,” Behnken said Satur­day morn­ing dur­ing a farewell cer­e­mony on the space sta­tion.

At the cer­e­mony, Hur­ley and Behnken gath­ered with their fel­low sta­tion crew­mates, NASA’s Chris Cas­sidy and cos­mo­nauts Ana­toly Ivan­ishin and Ivan Vag­ner. Cas­sidy handed Hur­ley an Amer­i­can flag that was brought up to the sta­tion on the last space shut­tle mis­sion in 2011. Hur­ley, a mem­ber of that flight, now gets to bring it home, mark­ing the restora­tion of hu­man space­flight from Amer­i­can soil.

“This flag has spent some time up here, on the or­der of nine years,” Hur­ley said. “I’m very proud to re­turn this flag home and see what’s next for it on its jour­ney to the moon.”

Just after the suc­cess­ful launch of the space­craft into orbit, Elon Musk, SpaceX’s founder, said “there’s an ar­gu­ment that the re­turn is more dan­ger­ous in some ways than the as­cent. So we don’t want to de­clare vic­tory yet. We need to bring them home safely, make sure that we’re do­ing ev­ery­thing we can to min­i­mize the risk of reen­try and re­turn.”

Think­ing about the as­tro­nauts and their fam­i­lies, Musk be­came emo­tional, un­able to speak. “I’m get­ting choked up. . . . We’re go­ing to do ev­ery­thing we can to make sure they get home safely.”

SpaceX started putting pic­tures of Hur­ley and Behnken on work or­ders to re­mind em­ploy­ees that lives were at stake. Re­cently they had another re­minder. Behnken’s wife, Me­gan McArthur, also a NASA as­tro­naut, was cho­sen to fly on a SpaceX flight next spring. To pre­pare, she re­cently spent a few days at the com­pany’s head­quar­ters.

In many ways, re­turn­ing to Earth is more per­ilous than es­cap­ing it.

Get­ting into orbit re­quires an enor­mous amount of en­ergy. The space­craft goes from sit­ting still atop a rocket on the launch­pad to chas­ing the space sta­tion at 17,500 mph in a mat­ter of min­utes. Com­ing home re­quires do­ing the re­verse, shed­ding all that en­ergy quickly. Fric­tion with the thick­en­ing at­mos­phere will gen­er­ate a tremen­dous amount of heat that will en­gulf the space­craft in a fire­ball.

“Out the win­dow, it’s all orange, and it’s glow­ing, and it’s quite a sight,” said Gar­rett Reis­man, a for­mer as­tro­naut who flew two shut­tle mis­sions. “But you don’t feel any­thing. You know you don’t want to be out there be­cause its thou­sands of de­grees, but on the in­side it’s pretty cool. It’s very com­fort­able.”

At mis­sion con­trol, NASA and SpaceX of­fi­cials won’t be so com­fort­able. As the fire­ball en­velops the space­craft, test­ing the heat shield, com­mu­ni­ca­tion with the as­tro­nauts will be lost. The black­out runs about six min­utes, but it will feel much longer.

Dur­ing Apollo 13, the nearly cat­a­strophic mis­sion, the black­out lasted for what seemed like forever, said Gerry Grif­fin, a leg­endary for­mer flight di­rec­tor at NASA dur­ing the Apollo era.

The cap­com, the per­son at mis­sion con­trol com­mu­ni­cat­ing with the as­tro­nauts, “kept call­ing Apollo 13. ‘This is Hous­ton,’ ” he re­called. “And noth­ing. He went on for two min­utes. You could hear a pin drop in that con­trol cen­ter.”

Un­like the shut­tle, which landed on a run­way, the Dragon space­craft is some­thing of a throw­back, a cap­sule that will land in wa­ter un­der para­chutes. Para­chutes are an old tech­nol­ogy but a tricky one, and SpaceX has strug­gled with the de­sign. Last year it suf­fered a fail­ure dur­ing a test of the para­chute sys­tem that ul­ti­mately prompted the com­pany to upgrade.

The up­graded ver­sion uses a stronger ma­te­rial in the lines that run to the canopy and a new stitch­ing in­tended to han­dle the loads at de­ploy­ment.

“Para­chutes are way harder than they look,” Musk said in an in­ter­view with The Wash­ing­ton Post in the days lead­ing up to the launch. “The Apollo pro­gram ac­tu­ally had a real morale is­sue with the para­chutes be­cause they were so . . . hard. They had peo­ple quit­ting over how hard the para­chutes were. And then, you know, we almost had peo­ple quit at SpaceX over how hard the para­chutes were. I mean, they sol­diered though, but man, the para­chutes are hard.”

If all goes well, two drogue para­chutes will de­ploy when the space­craft’s al­ti­tude is about 18,000 feet, trav­el­ing at about 350 mph. Then, as the drogue chutes slow the cap­sule to about 119 mph, four main para­chutes should de­ploy at about 6,000 feet.

At a news con­fer­ence late last year, Musk said the Mark 3 para­chutes are “prob­a­bly 10 times safer” than the Mark 2 ver­sion. “In my opin­ion they are the best para­chutes ever. By a lot.”

Since the Apollo era, para­chute de­sign has come a long way, es­pe­cially in the de­vel­op­ment of light­weight but stronger ma­te­ri­als, said Kurt Hempe, the di­rec­tor of space busi­ness for Air­borne Sys­tems, which de­signs para­chutes for SpaceX and sev­eral other com­pa­nies.

“But test­ing is ab­so­lutely an or­deal,” he said. “One of the big things we do to­day that they couldn’t do then was cre­ate com­puter models. We can come up with a model and sim­u­late be­fore we go fly. And then we go fly and we com­pare the data re­sults with the model we de­vel­oped.”

NASA and SpaceX have picked out seven dif­fer­ent land­ing sites along the east and west coasts of Florida, rang­ing from about 22 nau­ti­cal miles from shore to 175. Two re­cov­ery ships will be ready to speed to the space­craft once it ar­rives.

Ad­just­ing to Earth’s grav­ity is al­ways a dif­fi­cult tran­si­tion for as­tro­nauts, but land­ing in the wa­ter makes it even harder.

“You feel sick and you’re walk­ing like a drunken sailor, if you’re walk­ing at all,” Reis­man said. “Cou­ple that with land­ing in the ocean, bob­bing up and down, even in rel­a­tively calm wa­ter, it’s go­ing to be un­pleas­ant.”

The wa­ter land­ing in it­self presents a chal­lenge. Mer­cury as­tro­naut Gus Gris­som nearly drowned after his space­craft splashed down in 1961 and his Lib­erty Bell 7 space­craft sank after the hatch blew early.

That’s why the NASA and SpaceX teams will be hold­ing their breath un­til they see Hur­ley and Behnken safely aboard the re­cov­ery ves­sel.

“We didn’t cel­e­brate any­thing in the con­trol cen­ter un­til the guys stepped out on the car­rier deck,” said Grif­fin, the Apollo-era flight di­rec­tor. “That’s when we lit our cigars.”

Dur­ing the novel coro­n­avirus pan­demic, how­ever, that won’t be likely. NASA is tak­ing ex­tra pre­cau­tions to pro­tect work­ers and the as­tro­nauts, in­clud­ing test­ing peo­ple who come in con­tact with the as­tro­nauts. And every­one will be wear­ing masks.

NASA/AS­SO­CI­ATED PRESS

Bob Behnken, front left, and Doug Hur­ley wrap up their space sta­tion visit. “This flag has spent some time up here,” Hur­ley said. “I’m very proud to re­turn this flag home and see what’s next for it.”

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