Halfway Through ISS Mission, NASA Astronauts Anticipate Their Ride Back to Earth (stripes.com) 21
"They've been up there about a month now, floating around on the International Space Station, keeping tabs on their ride home," reports the Washington Post:
"Certainly, the highlight for both Doug and I was the initial arrival at space station, coming through the hatch again and being on board after several years of working on a new spacecraft," Behnken said in an interview from the station this week. Since then, he has performed two spacewalks with Cassidy, successfully replacing batteries on the outside of the station... Now, NASA and the astronauts are turning their focus to the return trip. At the moment, the space agency says the soonest Behnken and Hurley could return is Aug. 2.
If all goes well, the Dragon would undock from the station, fire its thrusters and descend through the atmosphere. The entire mission is a test to see how SpaceX's Dragon capsule performs, and while NASA said its ascent went flawlessly, there still are many risks ahead. As it plunges down, the thickening air will cause friction and generate enormous heat, testing the capsule's heat shield. Then the spacecraft's parachutes are to deploy to slow the vehicle further. SpaceX has struggled with its parachute designs in the past, however. "Parachutes are way harder than they look," Elon Musk said in an interview with The Post before the launch. "The Apollo program actually had a real morale issue with the parachutes because they were so damn 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 through, but, man, the parachutes are hard."
Another risk will be landing in the ocean. American astronauts have not splashed down in the water since 1975 — the Space Shuttles landed on land, as do the Russian Soyuz spacecraft. Behnken said he and Hurley expect to spend about an hour bobbing on the ocean surface before they are hoisted on the deck of a ship. SpaceX has been training extensively for the recovery mission, working to get the astronauts to safety as quickly as possible, but that will also be a key test.
If all goes well, the Dragon would undock from the station, fire its thrusters and descend through the atmosphere. The entire mission is a test to see how SpaceX's Dragon capsule performs, and while NASA said its ascent went flawlessly, there still are many risks ahead. As it plunges down, the thickening air will cause friction and generate enormous heat, testing the capsule's heat shield. Then the spacecraft's parachutes are to deploy to slow the vehicle further. SpaceX has struggled with its parachute designs in the past, however. "Parachutes are way harder than they look," Elon Musk said in an interview with The Post before the launch. "The Apollo program actually had a real morale issue with the parachutes because they were so damn 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 through, but, man, the parachutes are hard."
Another risk will be landing in the ocean. American astronauts have not splashed down in the water since 1975 — the Space Shuttles landed on land, as do the Russian Soyuz spacecraft. Behnken said he and Hurley expect to spend about an hour bobbing on the ocean surface before they are hoisted on the deck of a ship. SpaceX has been training extensively for the recovery mission, working to get the astronauts to safety as quickly as possible, but that will also be a key test.
Technology implements, archeypes motivate (Score:2)
As it plunges down, the thickening air will cause friction and generate enormous heat, testing the capsule's heat shield.
Behnken said he and Hurley expect to spend about an hour bobbing on the ocean surface before they are hoisted on the deck of a ship.
Sounds like a real Baptism of Fire.
Couldn't resist.
Compression heating (Score:5, Informative)
The "enormous heat" is not the result of "friction", except perhaps indirectly in the formation of the shock wave.
The Thermal Thicket of hypersonic flight (counterpart to the Sound Barrier of transonic flight) is the result of shock-wave generated compression. It is the same effect of a bicycle pump warming up, the ignition of the injected fuel in a Diesel engine, or one of those compression fire-starter gadgets.
Re:Compression heating (Score:4, Informative)
Thank you. As an avid Kerbal Space Program player, this explanation irked me. It is compression heating, not friction, that generates the vast majority of re-entry heat.
Re: (Score:2)
Probably one of the most underrated laws of physics.
Theories? (Score:1)
Re: Theories? (Score:2)
2 answers:
1) the "average" person can't balance their checkbook. The standard you're comparing against is pretty low. Socialize with people outside tech and you'll see
2) Elon is smarter than the average (see above about standards), but he's not some Uber genius. He got lucky at PayPal and now buys/hires very smart people to do stuff. He doesn't code or engineer anything. He's a business guy.
I assume you're aware he didn't found Tesla? He took it over and pushed out the founders and most of the origina
Re: Theories? (Score:1)
Lol brilliant, how'd I miss that one? Thanks!
Re: (Score:2)
I haven’t seen much evidence that Elon is significantly smarter than other people. In fact, he routinely does stupid stuff. But he does seem to be smart enough - and rich enough - to hire smart people and (usually) let them make the important decisions.
Re: (Score:2)
I haven’t seen much evidence that Elon is significantly smarter than other people.
You need to get out more.
am i the only person worried about QC (Score:1)
Tesla seems to have higher than average problems with Quality Control, even almost ten years after it first started mass production.
Does Space-X have similar issues?
It's compression, not friction (Score:5, Informative)
Re: (Score:2)
The heat is caused by compression of the air in front of the vehicle,
That is one way to look at it. I guess the point being made, is that heat is not "created" only on the hard surface of the craft, but by the shockwave ahead of it.
From the reference frame of the atmosphere, the kinetic (and potential) energy of the craft is transferred to the air molecules, which must mean it heats the air.
Hyper sonic fluid dynamics are very different from surface friction, or normal viscosity or air-resistance, but you can still call it friction.
"Who knew parachutes were so hard?" (Score:1)
Was it the perceived risk, or just how unpleasant the ride is? Aren't astronauts typically vetted to handle long periods of discomfort?
Re: (Score:2)
Was it the perceived risk, or just how unpleasant the ride is? Aren't astronauts typically vetted to handle long periods of discomfort?
I don’t think he’s referring to the astronauts; I think he means people in roles specifically related to the parachutes.
Re: (Score:1)
Getting parachutes to open properly, when they've been exposed to the cold of space for multiple days, followed by getting som