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Astronauts Pull Off Risky Spacewalk
dylanduck writes "A pair of NASA astronauts overcame an issue with a loose jet pack to make crucial repairs to the International Space Station, according to a story on New Scientist Space. No jet pack means not getting home if you inadvertently push yourself away from the space station and into space. That's a long goodbye that doesn't bear thinking about."
My compliments... I cannot imagine how tough that must of been.
Regards,
MBC1977,
(US Marine, College Student, and Good Guy!)
Regards,
MBC1977,
I jumped in and actually read this article because I couldn't bear not knowing if they had actually used duck tape to strap the jetpack to the astronaut. The sad fact is that they did not and NASA insists that it was in no danger of actually coming free... just a couple latches on the sides had come loose and the pack was both tethered to the astronaut and relatched while the astronauts were still in space actively pursuing their mission.
Gravity Sucks
How about using a rope tied to the suit? Seems like a low-tech solution, but might end up saving a life.
Someone around here will probably do the math, but I doubt that even if you push yourself off into the direction of the earth that it will be all that fast.
I suspect you're most likely to die from lack of oxygen than re-entry.
... but you find yourself drifting in space with no hope of rescue. Do you:
A. Take off helmet?
B. Let air run out and aphyxiate?
C. Pray that the galactic president is stealing a spaceship with the Infinite Improbability Drive in it?
I keep telling myself I'm not the desperate type.
This may be a stupid question, but haven't these NASA guys ever heard of the "rope" technology?
___
If you think big enough, you'll never have to do it.
It really doesn't matter what way you push off - down or 'back' (oppostite orbital direction), you end up going lower & slower, up or 'forward', higher & faster. You're still screwed, either way, but it won't be quick. (Well, unless you pop the suit open. That's quick.)
Have you been touched by his noodly appendage?
I'd point out the benefits of tying a piece of rope to the outside of the airlock, and tying the other end around the astronaut's waist.
It's an old, outdated solution, but I'd definitely go for it if the alternative was a slow death by radiation or oxygen starvation - that's just me...
Simon
Physicists get Hadrons!
The act of launching into space in a gigantic 22 year old space shuttle protected by ceramic tiles sounds pretty risky on its own.
Their suits hold enough oxygen to last up to 9 hours. If you slowly push away from the space station, you won't keep moving away from it in a straight line, because you and the space station are both orbiting the earth. In 46 minutes or so you may find yourself passing by it again.
The item they are referring to is the SAFER (Simplified Aid For EVA Rescue) backpack.
SAFER is not an integral part of the EMU, rather it is a derivative of the MMU which is exclusively for emergency (loss of tether) use.
SAFER can provide an adrift astronaut with about 10m/s Delta-V ie: If you're travelling away from the station at less than 10m/s you have a chance of getting back (although the closer you are to 10m/s the longer it takes to get back)
Ripping an new rectum in the fabric of spacetime.
Link
With that out of the way, let's take a look at orbital dynamics. You can't actually throw anything (or yourself) out of orbit--all you can do is throw an object, or move yourself, from one orbit to another. If you want to go to a higher orbit, you need to increase your speed in the direction you're traveling. If you want to go to a lower orbit, you need to decrease your speed. Just trying to thrust straight up or down won't work too well: Thrusting down, for instance, will lower you temporarily, but now you're going too fast to stay in that lower orbit, and you'll end up oscillating back above your original orbit. As science fiction author Larry Niven put it, "East takes you out, out takes you west, west takes you in, and in takes you east."
To get those baseballs to earth, you want to throw them back from the shuttle. Now they're traveling slower. The effect of this is to put them into an elliptical orbit, whose apogee--the point furthest from the center of the earth--is at the same height as the shuttle. If the orbit is elliptical enough, then its perigee--the point closest to the earth's center--will be closer than the surface of the earth, and the ball will collide with the earth after half an orbit or less. But if it doesn't hit the earth (and if we ignore atmospheric friction for the moment), it'll stay in that nice comfortable elliptical orbit indefinitely.
Now for the specific problem of astronauts throwing fastballs: The space station is at a height of about 390 km over the surface of the earth, for a total distance of 6,768 km from the center, and it's traveling at about 7,674 m/s. Our 93 MPH pitch translates to about 42 m/s, so the total speed of the ball is then about 7,632 m/s. Given that energy and angular momentum are conserved, it's straightforward (if a bit tedious) to calculate that, at perigee, the ball will be 6,623 km from the center of the earth, which is still a comfortable 245 km above the surface.
But this is all figured without the atmosphere. Won't friction from the topmost layers of the atmosphere cause the ball's orbit to decay, and eventually bring it down? Yes, but that would happen even without pitching the ball. If left on its own, the space station itself would eventually fall to earth, but they boost the orbit every so often to prevent that. In fact, that's why Mir was deliberately brought down: The Russians didn't want to keep boosting it any more, and they knew that eventually it would come down on its own.
I am an American but have no answer to this. Can a slashdotter enlighten an ignorant fellow?
I hope the buzz will be generated when Russia begins to produce rare-earth metals on the moon. Have a look at http://www.mosnews.com/news/2006/06/06/raremetalsm oon.shtml. For now, a slahdotter begs for some answers. Thanx.
This kind of thing is part of the job description. I mean, they're in a freefall environment with no air, and very wide temperature ranges. They get up there by strapping themselves to what is really a controlled bomb. I don't think anybody's going to argue that they're working a risky job. Some of them are going to die, and eventually we WILL lose a person to some accident that leaves them drifting away from the ship. It's good to know we have systems in place to try to prevent it, but it will happen eventually.
It's a dangerous job, some are going to die, and that's that. They do it anyway, and a lot of 'em take these sort of risks without a second thought. People need to stop thinking that everyone who gets sent up is going to come back. Sure, we should do our best to make sure that they do, but accidents will happen. The risk involved, and their willingness to go up to open up a new frontier, are two reasons why I have so much respect and admiration for them. I just wish I could be up there too.
Fill in your four or five-letter word of wisdom here _ _ _ _ _.
Or rather tethers.
Whenever the Astronauts are on EVA, they keep themselves tethered to either the station, the shuttle or a hardpoint on a robotic arm.
The 'SAFER' backpack in question is strictly for emergency use should the worst happen and an astronaut go adrift. SAFER is normally only employed when there is no vehicle readily available to effect a rescue (ie the Shuttle is docked so it cannot persue a drifting astronaut in a hurry).
Ripping an new rectum in the fabric of spacetime.
Space Travel is "newsworthy" again.
Too bad it took the death of several astronauts to draw peoples' attention to the risks these souls take for the sake of scientific progress.
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Yes I realize that there would probably never be a situation for it to be used "fight to the death" and all. But, if one had to kill themselves in space, personally a pill that slips one into a deep sleep and then death in my opinion would be a lot more respectable in my opinion, more peaceful, and a hell of a lot less violent and painful than simply exposing oneself to a vacuum.
Having my blood boil, my skin shrink, and my lungs explode doesn't sound like a good way to go.
Libertas in infinitum
To sum it up, though, the total distance from the center of the orbited body and the orbiting object is proportional to the square of the velocity. Small change in velocity = not-quite so small, but still pretty small, change in orbital distance.
Have you been touched by his noodly appendage?
D. Hope that CowboyNeal acquires a Tok'ra cargo ship to come save you?
Is it possible for them to use their oxygen supply as a kind of jet pack? The oxygen must be under pressure, so they could disconnect the tube, hold their breath and aim carefully....
I like my coffee the way I like my women - roasted and ground up into little tiny pieces.
It reminded me a bit of this (real) picture.
Beware: In C++, your friends can see your privates!
The jet pack is great, but the astronauts don't put their lives entirely on them. Actually, what really make the EVA safe are two tethers, linking the astronauts to the ISS. The issue with the jet pack was that the danger of it becoming space debris, what could put the ISS in danger. Check it out at space.com or any really serious space news site.
I grew up in a (canadian) military family, and we always had a supply of that army-green duct tape handy. The old man referred to it as "gun tape" because it was often used for field repair of training weapon stocks (which were often in poor repair).