Road Bike, Cycling Forums banner
1 - 20 of 22 Posts

·
δanned
Joined
·
7,005 Posts
Discussion Starter · #1 ·
If you're interested in watching this late tonight, Scott Kelly will be returning to Earth after spending a year on the ISS. This was an experiment to determine the long term effects of zero-G on human physiology.

Scott will be undocking at 2005 EST and performing his de-orbit burn at 2232 EST to make his landing an hour later.

Live coverage can be watched here: https://www.nasa.gov/feature/march-...tronaut-scott-kellys-return-after-yearinspace
 

·
Registered
Joined
·
11,089 Posts
Scott's got a twin brother that the physiologists will be using to help determine the effects of extended spaceflight...interesting science.
 

·
Registered
Joined
·
14,713 Posts
That's cool. Thanks for the reminder. To nit-pick a little, it's short of a year by about 3 1/2 weeks -- (it's 340 days). And it's not just Kelly; his fellow crewmember, cosmonaut Mikhail Korniyenko, who went up with him, will also be returning (it's the INTERNATIONAL Space Station, after all). And their mission is nowhere near the duration record, as four cosmonauts did longer stints on Mir, the longest Valeriy Polyakov for 437 days -- 3 months longer than Kelly and Korniyenko.

But cool, nonetheless, and I'll probably watch.
 

·
Registered
Joined
·
15,615 Posts
So the commute from the space station back to earth takes about three hours. I envision that it would be quicker, like dropping a rock from a plane, but it's probably a bit more complicated than that!
 

·
Registered
Joined
·
14,713 Posts
So the commute from the space station back to earth takes about three hours. I envision that it would be quicker, like dropping a rock from a plane, but it's probably a bit more complicated than that!
Three hours from undocking to landing, but most of that is just getting ready. The "commute" doesn't really start until the de-orbit burn, and then it's less than an hour to impact.

It's not really much like dropping a rock from a plane. The plane and the rock are being held up by aerodynamic forces on the plane, and as soon as the rock loses that contact, gravity begins accelerating it downward. The spacecraft in orbit is just coasting. Nothing is holding it up. Its momentum is just carrying it beyond the curve of the earth at the same rate gravity is pulling it downward, so it stays at the same altitude. When the capsule separates, it stays in the same orbit, still coasting, until they fire some rockets to slow it down, and then it starts falling. They only have to scrub a few hundred miles per hour off the speed (the orbital speed is a little over 17,000 mph) for the orbit to drop low enough to encounter significant atmosphere, and then friction with the air slows it down rapidly (and makes it very hot).

Probably way more than you wanted to know. Shouldn't get an old space geek started.
 

·
Registered
Joined
·
6,018 Posts
Three hours from undocking to landing, but most of that is just getting ready. The "commute" doesn't really start until the de-orbit burn, and then it's less than an hour to impact.

It's not really much like dropping a rock from a plane. The plane and the rock are being held up by aerodynamic forces on the plane, and as soon as the rock loses that contact, gravity begins accelerating it downward. The spacecraft in orbit is just coasting. Nothing is holding it up. Its momentum is just carrying it beyond the curve of the earth at the same rate gravity is pulling it downward, so it stays at the same altitude. When the capsule separates, it stays in the same orbit, still coasting, until they fire some rockets to slow it down, and then it starts falling. They only have to scrub a few hundred miles per hour off the speed (the orbital speed is a little over 17,000 mph) for the orbit to drop low enough to encounter significant atmosphere, and then friction with the air slows it down rapidly (and makes it very hot).

Probably way more than you wanted to know. Shouldn't get an old space geek started.
Can't they just use the transporter?
 

·
Registered
Joined
·
2,771 Posts
So you think. I have it on good word he's not going to take the exit for earth.
 

·
Registered
Joined
·
2,471 Posts
Scott's got a twin brother that the physiologists will be using to help determine the effects of extended spaceflight...interesting science.
That made me realize that twins have an unfair advantage in getting picked by NASA for missions like this one. Not fair!
 

·
Registered
Joined
·
14,713 Posts
That made me realize that twins have an unfair advantage in getting picked by NASA for missions like this one. Not fair!
If by "missions like this one" you mean comparing twins, well, there's no avoiding this. If you mean long spaceflights, or spaceflights in general, there doesn't seem historically to be much advantage. The Kellys are not just the only twins to have flown in space, they're the only siblings.
 

·
Registered
Joined
·
14,713 Posts
No graphene (sp??) elevator yet, either.

JC- you can geek out all you want! I love learning about this stuff.

Guess it's not as simple as Baumgartner Cat would have one believe.
Baumgartner, of course, was in a balloon, not in orbit. So he was basically the rock falling out of the airplane. I never saw the cat video before. Funny.

You're pretty geeky yourself, to have heard of the space elevator. Have you read Arthur C. Clarke's "The Fountains of Paradise"? In 1979, he envisioned a space elevator using filaments of crystalline carbon, well before anyone was talking about nanotubes or graphene. It's a great book.
 

·
Registered
Joined
·
15,615 Posts
I just read the science books as they arrive from my FIL. He’s currently reading something about Faraday; I told him to send me a comic book so my brain can rest a bit! Makes him very happy that somebody in the family is sharing his interest.
 

·
Eddy 53:11
Joined
·
3,165 Posts
Sad, most folks didn't even know he and others were up there.
 

·
Registered
Joined
·
6,018 Posts
Baumgartner, of course, was in a balloon, not in orbit. So he was basically the rock falling out of the airplane. I never saw the cat video before. Funny.

You're pretty geeky yourself, to have heard of the space elevator. Have you read Arthur C. Clarke's "The Fountains of Paradise"? In 1979, he envisioned a space elevator using filaments of crystalline carbon, well before anyone was talking about nanotubes or graphene. It's a great book.
I'm a fan of most of Clarkes's books including that one. Robinson's SF novel Red Mars also uses a space elevator. Personally I find riding in a elevator comfortable. No one makes eye contact and there are personal space issues. So the idea an hour elevator ride up to a tethered satellite is not that appealing
 

·
Registered
Joined
·
11,089 Posts
watched the PBS show about the Kelly and the ISS last nite...

it would a very interesting place to spend a few days in, but def not somewhere I'd want to be for 10 months...interior spaces looked tiny and cramped. seems like the 'glamor' of space travel would get old pretty quickly.

and if one of the other crew members got on your nerves, it could get ugly.
 

·
Registered
Joined
·
15,615 Posts
watched the PBS show about the Kelly and the ISS last nite...

it would a very interesting place to spend a few days in, but def not somewhere I'd want to be for 10 months...interior spaces looked tiny and cramped. seems like the 'glamor' of space travel would get old pretty quickly.

and if one of the other crew members got on your nerves, it could get ugly.
Watched that too! Impressed that the ending was so up-to-date.

The screening process must be pretty thorough for psychological issues, plus they never seem to lose sight of the fact that they're so fortunate to be among the very few that get to experience space like that. Also, they're kept pretty busy.
 

·
Registered
Escorted from the White House
Joined
·
36,949 Posts
Apparently a lot of the purpose of the mission was to sort of 'dry run' a manned Mars mission... long-duration, environmental effects (gravity, radiation), psychological stress, etc. etc

Astronaut Scott Kelly: Mars mission is possible - CNN.com


sidenote: One thing these articles never seem to mention ('cuz the writers aren't scientists or engineers)... the effects of zero-gravity can largely be dodged in long-duration spaceflight, as you can just spin the spacecraft for artificial gravity (i.e. centrifugal or centripetal force... always forget which it is).

This however does not explain why NASA keeps harping on the zero-gee thing... apparently some don't want their research to be 'de-justified'.

What would be more useful is research into the effects of partial gravity on the human body. The most likely Mars mission profile, after all, is 6 months outbound, 18 months on the Martian surface (@ 0.38g), and then 6 months to get back.






.
 
1 - 20 of 22 Posts
Top