Cooling Pump Malfunction On ISS

eldavojohn writes "On Saturday at 8pm GMT, the crew of the International Space Station awoke to alarm bells as one of two ammonia pumps shut down due to a spike in power. Their backup cooling (Loop B) is functioning as designed and NASA released an official statement: 'The crew is in no danger, but will need to work additional troubleshooting on Sunday to keep the station in a stable configuration, including the installation of a jumper cable to maintain proper cooling to the Zarya module in the Russian segment.'"

Comments

HOWTO: Fixing stuff in space

[tomhudson]

1) Where's the Duct Tape?

2) Duct tape something ("including the installation of a jumper cable to maintain proper cooling to the Zarya module in the Russian segment");

3) Problem solved!

Re:HOWTO: Fixing stuff in space

[SirRedTooth]

The aliens did it.

Re:HOWTO: Fixing stuff in space

[blackraven14250]

....are you saying they have advanced goost tape technology?!?

Re:HOWTO: Fixing stuff in space

[mtmra70]

Gaffer tape is far superior in just about every way.

Is Feature!

[DWMorse]

Our cooling pump is now, for your convenience, a heating pump. For survival in the cold of space.

Re:Is Feature!

[ILuvRamen]

You're right! In fact, why don't they just crack a window? It is indeed very cold in space lol.

Ditch the pump...

[human-cyborg]

They should develop artificial gravity. That way their absorption chillers won't need pumps.

Much simpler.

Re:Ditch the pump...

[human-cyborg]

<sarcasm>

Much simpler.

</sarcasm>

Better?

Re:Ditch the pump...

[vlm]

They should develop artificial gravity. That way their absorption chillers won't need pumps.

Much simpler.

Capillary action heat pipes work even better than pumped absorption chillers, and are even simpler than absorption chillers or artificial gravity. I'm sure we'll discover, this being a NASA project, that some important congressman's vote was purchased by someone in his district manufacturing the pumps. It is theoretically possible NASA made a design choice based on technical reasons such as heat pipes being heavier per watt, although it seems unlikely they'd use criteria like that.

Re:Ditch the pump...

[slick7]

They should develop artificial gravity. That way their absorption chillers won't need pumps.

Much simpler.

This sounds like a production manager. Failure to perform periodic preventative maintenance carries a cost.
Reactive maintenance = Crisis management, sufficient for the short term, sucks for the long term.

8pm EDT

[RockMFR]

8pm EDT, not GMT.

Re:frist psot

[Anonymous Coward]

frist psot

Wrong. According to the article, it's more the frosty piss (or the lack thereof) they are worrying about ;-)

Why human presence still matters

[mangu]

This is why it's still important to have humans in the loop.

We will most likely have human-equivalent machine intelligence in a few decades, but at this moment a piece of duct tape in human hands can do miracles that no amount of planning, programming, and design could allow a machine to perform.

Re:Why human presence still matters

[yodleboy]

wait a sec, if there were no humans on the ISS, much of its complexity would be unnecessary, eliminating the need to have humans in the loop. Specifically, i'm thinking of all the components that make it able to support human life, which seem to have a higher incidence of failure/issue. It's always a toilet or a/c unit freaking out up there.

Re:Why human presence still matters

[Rich0]

Yup - would they even need cooling if it weren't for the people?

Ditto for the hubble. People talk about it like it was a great victory for science that the space shuttle could fix it.

Instead of launching special rescue missions with the shuttle they could have:

1. Made the hubble servicable by robots.
2. Just made a new hubble every few years. Forget upgrades, just replace the whole thing.

The advantage of #2 is that instead of putting up a cutting-edge telescope and making it last 20 years, you just put up a pretty nice one, and make it last 5 years. Then you put up another pretty nice one in 5 years. Chances are the pretty nice one you build 5 years from now is nicer than the cutting edge one you put up this year.

The only part of the hubble that is probably worth recycling is the mirror, since the technology for mirrors hasn't changed much in the last 100 years (unless it can go adaptive/etc). So, put the mirror in some detachable module and have a robot swap it out with the rest of a new telescope. The mirror doesn't need any moving parts so it should last forever.

Re:Why human presence still matters

[vlm]

The only part of the hubble that is probably worth recycling is the mirror, since the technology for mirrors hasn't changed much in the last 100 years (unless it can go adaptive/etc) .... The mirror doesn't need any moving parts so it should last forever.

One part you're missing is the decay rate. True the technology of mirrors hasn't changed, but that doesn't mean they'll last, unmaintained, forever.

I wonder how quickly the aluminum reflective layer oxidizes in space. Not much O2, but O+ ions are probably even worse. Also outgasing from the rest of the scope condensing back onto the mirror, although you could probably occasionally heat the mirror to clean it.

The mirror will not last forever, or at least the reflective layer will not. It may, however, last a long time.

The other part you're missing is there is no need to launch 4 identical scopes in place of 1. Much more fun to launch an optimized widefield, an optimized IR, and optimized UV, an optimized visible wavelength. Maybe an interfereometer would be fun to launch?

Also its far cheaper to maintain a scope that is extremely nearby the space station, than it is to maintain with robots or shuttles, because you've already got guys in suits sitting there with preplanned resupply missions and perhaps even on-orbit spare parts.

Re:Why human presence still matters

[bloobloo]

I'd say that Hubble is still more than "pretty nice" now, 20 years after it was launched.

Re:Why human presence still matters

[mangu]

would they even need cooling if it weren't for the people?

Yes, they would. Thermal management is a big issue in any spacecraft, manned or not. There's no air to remove heat, everything has to be radiated away. However, if you make the surfaces able to radiate as much heat as possible this also means they will absorb as much heat when sunshine hits them.

1. Made the hubble servicable by robots.

Believe me, I've been doing this for a quarter of a century, a robot able to do maintenance in space is the wet dream of any spacecraft operator. Many satellites have failed because some trivial component failed, if it were simple or cheap to do it, space maintenance robots would be high on the priority list of the industry.

The advantage of #2 is that instead of putting up a cutting-edge telescope and making it last 20 years, you just put up a pretty nice one, and make it last 5 years

This goes against what's being done in spaceflight. Commercial or scientific, manned or not, all space equipment is always designed to last as long as possible.

Launch cost is such a big part of any mission that it makes sense to make equipment last longer in space. The difference in cost between a spacecraft that lasts 5 years and one that lasts 20 years is a small fraction of the cost of one launch, not to mention the three extra launches that would be needed.

I started working in the space industry in 1984, the first satellite I worked on then had an 8 years design life, the satellites I'm working on now have a 15 years design life.

Re:Why human presence still matters

[Jeremi]

Sounds like the right mentality to go to Mars/ Asteroids/ or anywhere else off this planet.

If you want a preview of what living off planet would be like, build yourself a water-tight metal cocoon, lock yourself inside, have it dropped to the bottom of the ocoean, and live inside it for the rest of your life -- no, you can't ever come back. Oh yeah, and for complete realism, you're not allowed to examine any fish or other lifeforms or collect any to eat, because off-planet, there won't be any.

Sorry to be a luddite flat-lander, and a bubble-burster on top of that, but after the first few weeks/months, living off-planet would be a hellish claustrophobic monotony punctuated only by the occasional crisis. By the time the first critical life-support system gave out and killed everyone, it's likely that most of the population wouldn't mind dying.

Perhaps someday terraforming or (less likely) discovery of human-friendly habitats will change that, but for now just there's no "there" there, and the costs for keeping humans alive indefinitely outside of Earth are incredibly high. We'd be much better off sending robots to explore until we develop the heavy-lift systems and/or automated-manufacturing technology to properly support an off-world colony.

Re:Why human presence still matters

[yodleboy]

"Sounds like the right mentality to go to Mars/ Asteroids/ or anywhere else off this planet. How many Luddite flat-landers does it take to screw in a light bulb?"

there's a world of difference between going to the moon/mars etc. and a station in low earth orbit, that was largely created to keep the space agencies of several countries employed and to justify the continuation of the shuttle program. How much more time do we need to spend in LEO? Imagine if Columbus and all those other great explorers had been content to just keep circling the Mediterranean...

I'm all for manned exploration, so long as it's exploration. If NASA says tomorrow they are willing to take some risk and send people to the moon to do something other than plant a flag again, or they want to go to mars and see how long they can keep a small group of people there, I will support it wholeheartedly and wish I could go along. What I won't support is off world make-work that turns the astronaut into a maintenance man or the guy that rotates the plants in some experiment.

Re:Why human presence still matters

[slick7]

If you want a preview of what living off planet would be like, build yourself a water-tight metal cocoon, lock yourself inside, have it dropped to the bottom of the ocean, and live inside it for the rest of your life..

Oh really?

Re:Why human presence still matters

[vlm]

after the first few weeks/months, living off-planet would be a hellish claustrophobic monotony punctuated only by the occasional crisis. By the time the first critical life-support system gave out and killed everyone, it's likely that most of the population wouldn't mind dying.

You make it sound like living in New York. I don't think it'll be that bad.

Re:Why human presence still matters

[Rich0]

Why go anywhere off-planet in the first place? With people, that is?

Is it just to say that we did it? Well, that's nice and all, and you're free to start collecting donations, but I'd rather not have myself and all my descendants for 30 years be paying the bills.

Is it to start some kind of viable off-planet existence? That actually makes sense to me, but in that case maybe we should go ahead and terraform the planet we intend to live on FIRST, and then start sending people to live on it. Just about all the research needed for this would be done on the ground, where it is a heck of a lot cheaper.

Is it to explore the solar system? Well, that is certainly done a lot cheaper with probes. Unhappy that we just have two of them stuck on one part of mars? Well, then go ahead and launch 50 of them, or build ones with wings or whatever. Any approach you take will be far cheaper if you leave out the people.

Calling somebody a luddite for not wanting to spend billions of dollars on orbiting stations is kind of like calling somebody a luddite for not owning their own learjet. It has nothing to do with not finding such things interesting or without value - they just do not have value proportionate to their cost.

Re:Why human presence still matters

[Rich0]

And how much nicer would it have been if it weren't designed to require shuttle visits, and if the cost of those visits went into other probes. Perhaps it could have gone into building more than one hubble in the first place.

A bit of a tangent, but why is it that when they build these things they don't just make more than one, or at least plan to make more than one? 95% of the cost is probably in the design, so if you just run off more than one you'd have a LOT more bang for the buck.

Re:Why human presence still matters

[Rich0]

Also its far cheaper to maintain a scope that is extremely nearby the space station, than it is to maintain with robots or shuttles.

Sure, if you don't account for the cost of the space station in the first place.

Why you'd spend hundreds of billions of dollars on a space station to save a few tens of millions of dollars on telescope repairs is beyond me...

Re:Why human presence still matters

[wgoodman]

Electronics still create heat. They're all in a heavily insulated box up there, the insulation is there to keep out radiation which would fry both fleshy and non fleshy inhabitants. It's not like they can just drop a huge heatsink on the outside, there's no air to blow past it and cool the damned thing. Humans up there or not, the AC is pretty damned important up there.

Re:Why human presence still matters

[Jeremi]

Yes, people live in nuclear submarines, often for months at a time. Then the submarine comes back to port, takes on fresh supplies and fuel, undergoes any necessary repairs and maintenance, and everyone gets off the boat for a while and enjoys some shore leave. It's the regular visits back to "Earth" that keep the crew alive, healthy, and sane -- and those visits would not be possible for people living at the bottom of some other gravity well.

Re:Why human presence still matters

[Mr. Freeman]

"Yup - would they even need cooling if it weren't for the people?"

Short answer: yes
Long answer: Yes, but a different kind. You have the sun radiating heat to the device and the device itself is radiating heat away. Balancing these two is generally performed by orienting the satellite in the proper manner and opening/closing certain panels to allow various things to radiate heat out of the satellite.

"Instead of launching special rescue missions with the shuttle they could have:

1. Made the Hubble serviceable by robots.
2. Just made a new Hubble every few years. Forget upgrades, just replace the whole thing."

You're fucking hilarious. "just making something serviceable by robots" is NOT an easy task. It's not a simple matter of "oh, just use bolt X instead of bolt Y" or something. Of course YOU STILL HAVE TO GET THE FUCKING ROBOTS UP THERE, it's not like we can put robots up there for free.

As for "just making a new Hubble every 5 years", are you mad? These things are expensive as hell. It would cost more to design, build, and launch a new telescope every five years that it would to just launch one telescope and service it. The things that break aren't amazingly complicated devices. The Hubble had several gyros go bad a couple years back. Are you suggesting that we should have junked the Hubble and launched an entirely new scope instead of flying 5 new gyroscopes up?

Re:Why human presence still matters

[Mr. Freeman]

"Why you'd spend hundreds of billions of dollars on a space station to save a few tens of millions of dollars on telescope repairs is beyond me..."

Because the space station isn't ONLY first servicing the scope. The station will be used for whatever science you do there anyway and every so often it will service the scope. The fact that this is beyond you means that you're a dipshit, it's really quite fucking obvious.

Re:Why human presence still matters

[Mr. Freeman]

"but why is it that when they build these things they don't just make more than one"

Because there's no point. You can't do twice as much science with two Hubble telescopes. Also, a lot of the money is in the design, but that doesn't mean that construction costs are negligible.

If you need a new engine in your car and you take it to a mechanic MOST of the cost will be the labor, but a new engine sure as hell ain't cheap. Same deal here. Scopes like this are built to extreme tolerances, which is expensive. They're built in clean rooms, which are expensive. They're launched into space, which is EXTREMELY EXPENSIVE.

Re:Why human presence still matters

[Mr. Freeman]

"If you want a preview of what living off planet would be like, build..."

Yeah, it'll suck for awhile. Of course, the idea is that you then DEVELOP the colony into a bigger colony, then you become self sufficient, etc. It's not a matter of "go sit on mars and do nothing", it's "go to mars, set up a bigger camp, and we'll send another ship in a few months with more people and more supplies, etc."

Also, he's not saying that we should go to mars RIGHT THE HELL NOW. He's saying that we need to actually work towards making this a possibility, that people need to be open to the idea of developing technology that will allow us to visit other planets. You're saying that we shouldn't try to make the technology to visit other planets until we have the technology to visit other planets... which makes no sense.

Re:Why human presence still matters

[Rich0]

My argument stands - what purpose does this station serve?

What science is done on the station that couldn't be done more effectively with probes?

What repairs does it do that couldn't be done more effectively with probes?

Now, if you already have a space station, taking advantage of it by leveraging marginal costs for marginal benefits is just good sense. However, nobody has made a case for why this thing is up there in the first place.

It seems like if you want to talk about probe repairs the argument will be, well, we already need it for the science anyway. Perhaps if we start talking about the science the argument will be, well, we already need it for the probe repairs anyway. Perhaps if we try to talk about both we'll end up talking about springboards to mars or whatever.

It seems like the ISS is just a means to an end, but nobody can actually tell me what that end is, beyond keeping a few industries going.

Re:Why human presence still matters

[Rich0]

You can't do twice as much science with two Hubble telescopes.

I had no idea that whoever ran the Hubble never had to turn down an application to make use of the thing. Perhaps if there were two of them more would get done more quickly.

No doubt there is some limit on the usefulness of a space-based telescope, but if we really were running out of useful things to do with the Hubble why did we bother fixing those gyros in the first place?

It seems like you're arguing that the Hubble is important enough to save, but not important enough to have more than one of. Are there any decisions at all associated with the Hubble program that perhaps looking back were not perfect, or is the issue simply that I'm questioning sacred cows?

Relax - I'm sure you're a smart guy and that you do great work. I'm not saying that there is no place at all for manned space programs, or for satellite repairs. I'm just questioning whether they really are cost-effective. For repairs at least the question is economically straightforward to answer if you have a full cost breakdown. For manned space in general you have to somehow quantify the benefits, which is mostly impossible without some agreement on the principles that will be used to do this.

Re:Why human presence still matters

[Rich0]

My point was that it should have been built so that things like gyros are replaceable, or that they don't break.

As far as launching robots goes - it is a LOT cheaper to launch a robot than a shuttle.

The cost of necessary repairs should of course be factored into the decision to launch the thing in the first place.

In any case, the decision to junk the Hubble and launch an entirely new scope seems to already have been made. :)

Re:Why human presence still matters

[slick7]

Yes, people live in nuclear submarines, often for months at a time. Then the submarine comes back to port, takes on fresh supplies and fuel, undergoes any necessary repairs and maintenance, and everyone gets off the boat for a while and enjoys some shore leave. It's the regular visits back to "Earth" that keep the crew alive, healthy, and sane -- and those visits would not be possible for people living at the bottom of some other gravity well.

Oh really?

Re:Why human presence still matters

[slick7]

"If you want a preview of what living off planet would be like, build..."

The technology is there, and has been there for decades. However, it will take a team effort, TEAM PLANET EARTH. Traveling to Mars or anywhere else, other than the Moon is nothing more than "a pig in a poke", A scam, a fool's errand. If you want to go on a trip you need several things before you go.
1. A place to depart from and to return.
2. You need to bring all the supplies you can possibly need. There are no motels, no McDonalds, no BP gas stations (yeah). This isn't 1492 nor is it 1849.
3. Nobody gets it right the first time, except perhaps N. Tesla. Practice, practice, practice. Make sure everything works, is repairable, can be upgraded, has backups, has backups, has backups.
4. Now for the crazy part, people. You cannot just send scientists and engineers, you need the ditch diggers, garbage men, plumbers and electricians, nurses and doctors, etc, etc, et al. A very large human presence is needed in near Earth space before you start to populate anywhere else.
5. Think up something that you would want in space.
Step into the future, now!

Re:Why human presence still matters

[slick7]

Why go anywhere off-planet in the first place? With people, that is?

Is it just to say that we did it? Well, that's nice and all, and you're free to start collecting donations, but I'd rather not have myself and all my descendants for 30 years be paying the bills.

Is it to start some kind of viable off-planet existence? That actually makes sense to me, but in that case maybe we should go ahead and terraform the planet we intend to live on FIRST, and then start sending people to live on it. Just about all the research needed for this would be done on the ground, where it is a heck of a lot cheaper.

Is it to explore the solar system? Well, that is certainly done a lot cheaper with probes. Unhappy that we just have two of them stuck on one part of mars? Well, then go ahead and launch 50 of them, or build ones with wings or whatever. Any approach you take will be far cheaper if you leave out the people.

Calling somebody a luddite for not wanting to spend billions of dollars on orbiting stations is kind of like calling somebody a luddite for not owning their own learjet. It has nothing to do with not finding such things interesting or without value - they just do not have value proportionate to their cost.

When a place gets crowded enough to require ID's, social collapse is not far away. It is time to go elsewhere. The best thing about space travel is that it made it possible to go elsewhere. - RAH

Re:Why human presence still matters

[Rich0]

Trust me, you're far more likely to get away with not having an ID in the hills of Kentucky than boarding a spacecraft...

Maybe AFTER we terraform mars that might be an option. Actually, I'm not sold on terraforming, just living in orbit in space stations is probably more sensible - AFTER the technology exists to allow this to be done cost-effectively.

Re:Why human presence still matters

[slick7]

Trust me, you're far more likely to get away with not having an ID in the hills of Kentucky than boarding a spacecraft...

You ain't from around here, are you boy?

Re:Sounds like Russian thing: JUMPER CABLES IN SPA

[human-cyborg]

What's weird about jumper cables in space? A set of heavy gauge wires that can take lots of current, with universal connectors on either end? Sounds incredibly versatile. I'd never leave Earth with out them, packed right next to my towel.

You much be one of those people who take your car to the dealer to get an oil change.

Hmm...

[fuzzyfuzzyfungus]

I'm surprised that they would be using ammonia coolants, rather than something more exotic and less toxic.

Ammonia makes perfect sense in industrial ice plants and rink chillers and stuff, being dirt cheap, and not especially dangerous when you have an entire planet's atmosphere to dilute the leaks. Plus, it doesn't have the Ozone-eating properties of the CFCs.

In space, though, everything is expensive by default, having been carried into earth orbit, there isn't much of an ozone layer to worry about, and you really don't have enough breathable atmosphere available to risk contaminating it with anything unpleasant. Ammonia seems like a curious choice.

Anybody know why they would have gone with that?

Re:Hmm...

[houghi]

Perhaps because everything else would need more (read heavier) equipment and thus would be costing other stuff they want to bring up there. Just guessing.

Re:Hmm...

[bloobloo]

Molecular weight of ammonia = 17
Molecular weight of R12 = 121

Re:Hmm...

[rickb928]

"not especially dangerous when you have an entire planet's atmosphere to dilute the leaks."

Apparently you've never been in a ice rink with an ammonia leak , or even a suspected one. Panic evacuation is the first response. Not enough atmosphere where the ammonia is actually used to dilute it sufficiently.

Re:Hmm...

[vlm]

I'm surprised that they would be using ammonia coolants, rather than something more exotic and less toxic ... Anybody know why they would have gone with that?

IF its an absorption cycle system, you just can't do better than ammonia. Its hard to find any refrigerant gas that dissolves better in water... absorption cycle is nice on planet earth, no moving parts, no lubricant compatibility issues. In space you need pumps, however.

On the other hand, if its a vapor-compression system like your fridge at home, yes it is in fact a pretty cruddy choice and any of the freon series would kick its butt (as a refrigerant, anyway)

On earth you can play games with gravity to prevent/reduce slugging the compressor in a vapor-compression system. Not sure how you do that in space. Slugging a compressor is when load/airflow is low and you feed a gulp of liquid into the intake instead of moderately hot gas. Its kind of a shock to the innards, its the pump equivalent of eating at Taco Bell...

http://en.wikipedia.org/wiki/Refrigeration#Cyclic_refrigeration

Re:Hmm...

[slick7]

I'm surprised that they would be using ammonia coolants, rather than something more exotic and less toxic.

Less toxic? Ammonia, R-12, R-134a, etc are un-breathable. The least toxic is water, unless you drown in it.
How about... Something a little more high tech?

Re:Hmm...

[DerekLyons]

The problem is that the ISS ultimately rejects heat by radiating it away through radiators mounted on the solar array wings - and water would freeze and plug up the radiators.
 
So instead, they use a water loop to cool the atmosphere and equipment, and then transfer that heat to the ammonia system which then circulates through the radiators. (It's pretty easy to design the system such that there is minimal ammonia piping (and thus a minimal chance of an accident) inside the manned spaces.) Since ammonia freezes at a much colder temperature than water, this means it's much easier to keep the coolant moving at a rate where it radiates enough heat to be useful but still stays warm enough to not freeze.
 
It's going to be a complex trade off to choose a coolant, and few people seem to realize that NASA does take into consideration cost and availability when making their choices. They aren't so good at controlling costs as they might be, which is understandable since overall they're working at the bleeding edge of engineering, but that doesn't mean they don't try.
 
And really, there's isn't much of a difference between ammonia or anything more exotic because even something 'safe' (like nitrogen for example) is still going to rapidly displace the oxygen from the air (that is, reduce the effective partial pressure) if there's a leak because of the small volume of the breathable atmosphere.

Re:Hmm...

[vlm]

Reason 3 which I forgot to include, is radiation turns ammonia into harmless H2 and N2. Little to no effect on the equipment or thermodynamic properties at any reasonable concentration. If you catch enough gammas to break down 50% of the refrigerant, roughly 50% of the crew mass would have been broken down, indicating bigger problems.

Radiation turns fluorocarbons into fluorine and assorted debris. fluorine, at any concentration, is not good in anything except fluorine tanks. Anthropomorphizing it a bit, F likes to halogenate hydrocarbons like pump oil or plain ole oily contaminants leading to all kinds of entertainment. Its just nasty stuff even at the lowest concentrations. I suppose you could design and install a nice heavy halogen trap, but you'd never Really Know about the internal corrosion levels of the pumps and pipes without very expensive continuous maintenance. The entire refrigeration system would need to be halogen compatible. On earth its not an issue due to low radiation levels and frankly if my A/C pipes corrode out its not life threatening anyway. But not so good of an idea in space.

Finally ammonia is high temperature stable and if you somehow manage to dissociate it anyway, the N2 and H2 are mostly harmless and can be flushed out. On the other hand, SOME of the fluorocarbons have pretty nasty icky byproducts if you overheat them, by, say, the pump shutting down in full sunlight for a long time.

Re:Hmm...

[Josh04]

Not mutually exclusive.

Re:Hmm...

[Pyrowolf]

I think the point is, you can't evacuate and have air to breathe away from the ice rink. They don't have that luxury.

Re:Hmm...

[mmontour]

On the other hand, if its a vapor-compression system like your fridge at home, yes it is in fact a pretty cruddy choice and any of the freon series would kick its butt (as a refrigerant, anyway)

In terms of performance, ammonia is one of the best refrigerants in vapor-compression systems. Freon is easier and safer for small systems but ammonia is preferred for large industrial applications.

Re:Hmm...

[TheLink]

Evacuation tends to take a different meaning in space...

Re:Hmm...

[vlm]

In terms of performance, ammonia is one of the best refrigerants in vapor-compression systems.

Yes, but that re-circularizes the argument, back to the original post that if you must have a leak into a confined space, like a space station, you'd have to try really hard to find a worse refrigerant than ammonia, so why in the world would NASA use it, etc. For toxicity reasons I'd still stand by my statement that it is a really cruddy refrigerant for a vapor compression cycle, unless you're doing absorption cycle, in which case its performance is so utterly fantastic I guess we'll have to over look the whole toxicity thing.

Its kind of like the scenario of using propane in a car air conditioner instead of R-22/R-134... Sure it's a tolerably good refrigerant and its pretty much drop in compatible with most lubricant oils, hoses, seals and other parts, but pressurized propane is a pretty cruddy choice for a (probably leaky) automobile air conditioner due to the whole flammability thing, even if its got a decent COP.

Re:Hmm...

[DerekLyons]

The ISS uses a cooling system - not a refrigeration system. The ammonia is used merely as a working fluid to convey heat from the station's interior to radiators, were it is rejected.

attitude control?

[Anonymous Coward]

> Once awake, space station astronauts powered down some attitude control systems

I wonder what the attitudes are now, without the control systems in place.

Re:attitude control?

[human-cyborg]

Seeing as they just woke up, I guess that would depend upon whether or not they're morning people.
But I'm guessing when you're in space, those lines start to blur.

Re:attitude control?

[slick7]

Once awake, space station astronauts powered down some attitude control systems

...and were snippy for the next 27 orbits.

Can't they just push start it?

[countertrolling]

Who's the most popular person at an alien wedding? The guy with the jumper cables...

Re:Can't they just push start it?

[Muad'Dave]

Is that your Beech? What happened to it? The wing looks like crumpled and burned aluminum foil.

Re:Sounds like Russian thing: JUMPER CABLES IN SPA

[Sarten-X]

Well of course you wouldn't leave without them, Mr. Human-Cyborg.

That said, I agree fully. There are certain people in this world who, given a problem and some small versatile components, can fashion a solution. I don't mean simply the ones titled "engineer"; it's more of a personality trait. Duct tape, jumper cables, a good pocketknife, plastic sheeting, and a skein of rope can solve most everyday problems, and many that aren't so everyday.

For a while, I carried a small coil of Romex 3-conductor wire in my trunk. I don't know how it got there, but when a screw fell out of my car door's latch 150 miles from home, it was nice to have materials to make a makeshift replacement. Just 2 inches of one of the conductor, folded in half, and threaded into the hole. The plastic insulation held as threads, and I had a working screw.

Zarya module in the Russian segment.

[countertrolling]

You guys make it sound like some kind of ghetto housing project.

Re:Zarya module in the Russian segment.

[slick7]

You guys make it sound like some kind of ghetto housing project.

...or West Virginia?

Ripley disabled to cooling for self-destruct

[Gothmolly]

I've seen this before - Ripley probably disabled the cooling as part of the self-destruct sequence.

Re:Sounds like Russian thing: JUMPER CABLES IN SPA

[human-cyborg]

Good example. I once fixed a car door latch with a hair elastic. Held for years.

This is why my office is so messy, you never know what 'junk' will be useful in a pinch.

Re:Sounds like Russian thing: JUMPER CABLES IN SPA

[slick7]

Well of course you wouldn't leave without them, Mr. Human-Cyborg.

That said, I agree fully. There are certain people in this world who, given a problem and some small versatile components, can fashion a solution. I don't mean simply the ones titled "engineer"; it's more of a personality trait. Duct tape, jumper cables, a good pocketknife, plastic sheeting, and a skein of rope can solve most everyday problems, and many that aren't so everyday.

For a while, I carried a small coil of Romex 3-conductor wire in my trunk. I don't know how it got there, but when a screw fell out of my car door's latch 150 miles from home, it was nice to have materials to make a makeshift replacement. Just 2 inches of one of the conductor, folded in half, and threaded into the hole. The plastic insulation held as threads, and I had a working screw.

...or better yet, carry AAA Plus, it's only $97 per year. For the ISS, I would go with SSS (Space Station Society) Plus because you get 4 free tows to a higher orbit each year.

Re:Sounds like Russian thing: JUMPER CABLES IN SPA

[PinkyGigglebrain]

My mother takes her car to the dealer for oil changes, but even she has a set of jumper cables in her car.

Re:Sounds like Russian thing: JUMPER CABLES IN SPA

[Sarten-X]

AAA would take an hour to reach me, just to bring a screw. I was on my way in five minutes, for free.

Re:Russia still can't build anything of quality

[ModernGeek]

in the words of Hank Hill, "it was before we knew the Russians were incompetent."

Leave the building!

[jandersen]

"In the case of a fire alarm, immediately leave the building and go to the Assembly Point.
Do not stop to pick up belongings or put on your clothes, and don't use the lift.

Thank you,

Your Fire Warden"

Re:Russia still can't build anything of quality

[Muad'Dave]

Yet the station relies on the Russian Progress modules for resupply, a Russian Soyuz module as an escape craft, and the only access to the station after the final shuttle launch will be via Russian Soyuz spacecraft, which "...is launched by the Soyuz rocket, the most frequently used and the most reliable launch vehicle in the world."

My opinion is that Russian equipment is solidly (over)built, simple to operate, and simply designed for reliability.