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."

Comments

I tip my hat to those brave men (or women)

[MBC1977]

My compliments... I cannot imagine how tough that must of been.

Regards,

MBC1977,
(US Marine, College Student, and Good Guy!)

Re:I tip my hat to those brave men (or women)

[darkmeridian]

Spacewalkers must have balls of steel. Prior to an early Gemini mission that involved the first U.S. spacewalk, the crewmember staying in the craft was instructed to cut the tether of the spacewalker in the event he could not return to the craft before they both ran out of oxygen. During the spacewalk, the suit ballooned up to a point where the spacewalker could not fit into the cramped confines of their primative spacecraft. Even though the spacewalker wasn't told of the standing orders to cut him loose in case of an emergency, he must have thought of it as time ticked down. Pretty much at the last second, he squeezed himself into the craft and secured the latch. Crew and vehicle returned safely to earth and later spacesuits were made more rigid.

There are apocryphal anecdotes that the crew of the Apollo missions were issued poison pins laced with cyanide just in case they could not get into a proper reentry slot and skipped off into space for eternity. I wonder if astronauts on spacewalks are told to depressurize if they find themselves irretrievably lost in space. (Is there even a way to intentionally depressurize their suits? I guess they can take it off, right, unless this requires some help.)

Moreover, at least something good is coming out of the International Space Station: modern experience in large-scale construction in outer space. Even though the ISS is a loss in terms of substantive science conducted, I would bet it has helped a lot in the applied sciences involving in building the structure. Not quite in terms of "make spacesuits more rigid" but probably in the minutiae of designing structures and methods of assembly that are easier using actual lessons learned.

Re:I tip my hat to those brave men (or women)

[roman_mir]

Spacewalkers must have balls of steel. - by the way in case of women, would that be tits of steel or eggs of steel? (I know, I know, they still say 'balls' of steel, but exactly which balls, the former or the latter? :)

Re:I tip my hat to those brave men (or women)

[introverted]

There are apocryphal anecdotes that the crew of the Apollo missions were issued poison pins laced with cyanide just in case they could not get into a proper reentry slot and skipped off into space for eternity.

The stories aren't apocryphal. I don't know if it's still there, but the Apollo exhibit at the Smithsonian's Air and Space museum used to have what was either one of the pills, or a (presumably inert) lookalike.

Re:I tip my hat to those brave men (or women)

[DerekLyons]

It pretty much comes down to whether you consider the Smithsonian (or me) to be reliable.

The Smithsonian's reliability isn't at issue - it's you, as you are the one making the report. (No offense.) On the other hand, multiple astronauts have categorically denied the presence of such pills.
 
 

And who knows? Maybe it's something that was present on earlier flights but not later ones.

Who knows? I know. I've read every astronaut biography - and those that mention the pills at all, categorically deny their existence. Not one NASA document describes their existence. Not one (of many) Smithsonian trip reports I've read over the years mentions the display. On the space history newgroup we've spent years looking for information about those pills - and have consistently come up dry.
 
That's a powerful lot of negative evidence.
 

(Idle speculation is one of the things at which the Internet excels. :-)

The other thing with which the internet abounds is individuals that wrongly assume the person randomly replying to them is in fact, like them, idly speculating - and not someone who actually knows something about the topic.

Duc(k|t) tape

[fbartho]

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.

Re:Duc(k|t) tape

[Stormwatch]

Originally, it WAS marketed as duck tape.

Re:Duc(k|t) tape

[kimvette]

No, it's Duck Tape. Duck Tape was marketed as a waterproofing tape, and never for ducts, because you know why? It SUCKS. It dries out, oxidizes, and flakes so if you use it to seal HVAC ducts, you'll have a really good seal for a few months and then a very leaky duct after that when the tape degrades.

The ripoff/copycat brands marketed their waterproof tape as "duct tape" for a couple of reasons:

  - because the seal is initially good, folks get suckered into relying on it, not realizing that once the ducts are buried behind sheetrock that they got screwed

  - confusion between the trademarked "Duck Tape" brand and "duct tape" marketing drivel which is fraudulent to begin with (because so-called "duct tape" sucks for ducts)

If you want a real "duct tape" look at adhesive tin or aluminum tape, not the so-called "duct tape" clones of Duck Tape.

If you want to play grammar nazi at least get it right.

Rope to the rescue!

[DeeZee]

How about using a rope tied to the suit? Seems like a low-tech solution, but might end up saving a life.

Re:Rope to the rescue!

[QuantumG]

All astronauts are tethered to the station on spacewalks, there was never any risk. This is just stupid sensationalism, as usual.

So not to be morbid or anything...

[Durrok]

... 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?

Re:So not to be morbid or anything...

[Beryllium Sphere(tm)]

You're a trained test pilot in that case, so you keep trying things as long as you're conscious, like throwing tools away from you to push you back (and then somehow canceling the spin -- maybe tossing them like a softball is best).

Supposedly there are cockpit tapes from test flights along the lines of "Option A completed, result negative, option B completed, results negative, option C WHAM".

Re:So not to be morbid or anything...

[Iron Sun]

It doesn't work that way. Orbital mechanics often works counterintuitively. There are no figures in this article, but it states that a good push off from the ISS would send you perhaps 3 kilometers away from the ISS, inot an orbit that would intersect with the station one or twice per 90 minute orbit. The space suits are good for 7+ hours, so provided you didn't do it at the end of the EVA there would be plenty of time to pick you up.

uhhm, rope?

[RelliK]

This may be a stupid question, but haven't these NASA guys ever heard of the "rope" technology?

Re:uhhm, rope?

[cyclone96]

Here's your answer (for what's it's worth, I work for NASA).

The shuttle airlock is in the cargo bay at the base of the docking system. It's literally the tunnel between the vehicles. In order to go out the shuttle airlock, the hatches must be closed between the vehicles and both crews have to go back to their "home" spacecraft (since otherwise they'd be isolated from their rides home). Obviously we don't want the entire shuttle crew hanging out all day in the orbiter when there is work to do on ISS. Additionally, the folks doing most of the robotic arm work in ISS are actually shuttle crew members (since they can be trained on flight specific tasks very close to the mission) and they need to be able to go between the vehicles.

Quest doesn't suffer from this problem since it's hanging off the side. Additionally, depressurizing the shuttle airlock sometime introduces some control system challenges because it loses it's rigidity somewhat and it's part of the structural backbone of the vehicle, so that's nice to avoid.

That being said, the capability remains to go out the shuttle airlock if need be.

Pretty hard push....

[Chmcginn]

There's no way a person could push hard enough to get themselves into atmosphere before they froze/suffocated. Everyhing up there is already moving at about 30,000 kilometers per hour - that's what sets their orbital distance at 350 km. Even assuming you pushed off hard enough to go 30 km/ hr relative to the station, that's still a total change of less than .1% in orbital momentum.

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.)

Re:Pretty hard push....

[Andy Gardner]

Well, unless you pop the suit open. That's quick.

You would be suprised

Re:Pretty hard push....

[tftp]

Now if you thrust in towards the mass your orbiting, well im actually not quite sure what would happen but intuitively i dont think you would lower your orbit.

This will lower your orbit and increase your orbital speed at the same time. The trick here is that you have a lot of kinetic energy that you obtained through the launch, and that energy is not going anywhere, as far as your pushes are concerned. Human power (a few hundred Watts) is not enough to affect any change during the astronaut's lifetime.

See Equation of motion.

And if you follow through the links, you will find precomputed numbers for this very case:

The International Space Station has an orbital period of 91.74 minutes, hence the semi-major axis is 6738 km [1].
The energy is 29.6 MJ/kg [2]: the potential energy is 59.2 MJ/kg, and the kinetic energy 29.6 MJ/kg. Compare with the potential energy at the surface, which is 62.6 MJ/kg. The extra potential energy is 3.4 MJ/kg, the total extra energy is 33.0 MJ/kg.

This roughly means that if you weigh 100 kg you need to negate about 3.3 GJ to fall to the ground, and if your mechanical power is 1000W (a trained athlete, unencumbered with a spacesuit and provided with all the food and oxygen you need) you still need about 1000 hours of pushing, assuming that there is always something to push against. For example, you can carry a spring-driven pellet gun; however the weight of the pellets that you have to carry will slow your descent drastically. This does not take the atmosphere into account, but you definitely will find it there, briefly.

I don't

[Space cowboy]

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

Re:I don't

[starbird]

Right. This is why each participant in the EVA is attached to 2 thethers at all times. Either 50' or 85', depending on where they are and where they're going.

The backpack is a tritary backup in case both tethers are released.

not _that_ risky

[dtfinch]

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.

Re:not _that_ risky

[targo]

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 parent actually has an interesting point but is simply bad at explaining himself, stop modding him down :)
1) The height of one's orbit is directly related to the speed - the higher the speed, the higher your orbit
2) If you push yourself away so that your earth-relative speed changes (e.g. forward or backward), you will get to a higher or lower orbit, and cannot get back to the station
3) However, if your earth-relative speed doesn't change (e.g. if you push yourself off perpendicularly), you will keep orbiting the Earth at the same height as before. So we'll have two orbits (ISS and you) with
a) same height and speed
b) slightly different angles
c) you were at the same point at some point in time
These orbits will keep intersecting in two points, the original point, and one right across the Earth, so it's actually possible to get back.

SAFER != MMU or EMU

[reality-bytes]

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)

I wonder...

[bogaboga]

I wonder why any issue surrounding NASA and the space shuttle gets a lot of buzz in the US news media. Why? Similar accomplishments by the Russians do not get as much attention, yet they are equally daunting if not more. Is it an American `thing' or what?

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.

Re:Suicide pill?

[yeremein]

From the prologue of Apollo 13 by Jim Lovell & Jeffrey Kluger:

Stories about poison pills always made Jim Lovell laugh. Poison pills! Forget about it! First of all, there just weren't any situations in which you'd ever really consider making an early exit. And even if there were, you had a hell of a lot of easier ways to do it than poison pills. The command module had a crank for the cabin vent, after all. One turn of the handle, and five pounds per square inch of cozy capsule pressure would instantly be exposed to the zero pounds-per-square-inch pressure of space. Whatever air was left in your lungs would explode out in an angry rush, your blood would quickly--and literally--boil, and your traumatized system would simply shut up shop. The whole thing would be over in just a few seconds. It was no slower, really, than some ridiculous poison pill, and it was a lot more respectable.

And Ropes they have!

[reality-bytes]

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).

Re:Suicide pill?

[SonicSpike]

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.

Re:Not true

[cyclone96]

In theory you could move the space station, in practice you could not. The space station isn't really designed to be maneuvered in real time by the crew (or the ground, for that matter). Attitude maneuvers can be accomplished fairly quickly (less than an hour if you really had to), but translational maneuvers (which would be required to go grab an astronaut) take in excess of a day to put together and execute. Space station normally bores holes in the sky, so it that capability was never designed in (like it was on the orbiter or Soyuz). The orbiter can't undock quickly enough to go get them, either - at least not without compromising the safety of the rest of the crew and the vehicles themselves.

Which is the whole reason why SAFER was developed. Back in the shuttle-only days, going and grabbing the lost crew member on a double tether failure was a viable option, today it isn't.

Misinformation

[magsilva]

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.