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Space Station Spacewalkers Stymied By Stubborn Bolt
Hugh Pickens writes "Reuters reports that astronauts at the International Space Station ran into problems after removing the station's 100-kg power-switching unit, one of four used in a system that distributes electrical power generated by the station's solar array wings, and were stymied after repeated attempts to attach the new device failed when a bolt jammed, preventing astronauts from hooking it up into the station's power grid. Japanese Astronaut Akihiko Hoshide got the bolt to turn nine times but engineers need 15 turns to secure the power-switching unit. 'We're kind of at a loss of what else we can try,' said astronaut Jack Fischer at NASA's Mission Control Center in Houston after more than an hour of trouble-shooting. 'If you guys have any thoughts or ideas or brilliant schemes on what we can do, let us know.' Hoshide suggested using a tool that provides more force on bolts, but NASA engineers are reluctant to try anything that could make the situation worse and as the spacewalk slipped past seven hours, flight controllers told the astronauts to tether the unit in place, clean up their tools and head back into the station's airlock. NASA officials says the failure to secure the new unit won't disrupt station operations but it will force engineers to carefully distribute electrical power from three operating units to various station systems and says another attempt to install the power distributor could come as early as next week if engineers can figure out what to do with the stubborn bolt. 'We're going to figure it out another day,' says Fischer."
you're obviously not an engineer. the big things are made up out of tiny things. its always* a tiny things that gets you
Common error with multiple fasteners. Loosen the other bolts, then tighten them all evenly.
You could try WD-40, but I suspect that Newton's Third Law outlaws use of aerosol cans in space.
They should have used self-sealing stem bolts, they don't have this problem.
A squid eating dough in a polyethylene bag is fast and bulbous, got me?
Just hammer it in with a crescent wrench.. what's the matter with these people?
“He’s not deformed, he’s just drunk!”
Oh, come on, this thing weights zero in orbit, they can just scotch-tape it in place! ;)
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Sounds like they got the bolt cross threaded.
Just need to back out the bolt, run a thread chaser through to clean up the threads and try again.
And if NASA has an Amazon Prime membership, Amazon will have it delivered to the space station by Wednesday (if they pay the $3.99 overnight delivery fee). There may also be a small surcharge for orbital delivery.
Take it outside and do it.
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Presumably you also test your systems in a vacuum and 300C swings in temperature? Conditions in space are very hard to replicate on the ground and all sorts of weird things happen to metal-on-metal contact in vacuum. The problem here could be (a guess/example) something related to 7% extra torque being needed because of a temperature swing which then bends the male threads slightly, exposing an non-oxidised layer which then vacuum welds to the female thread. Could be a lot of things, and you can't test space technology 100% without, you know, putting it into space.
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Mechanical design is very different, I've done both. You're working with analogue systems, which means that everything has a tolerance - let's compare it to 'bits of accuracy'. You can go to a higher accuracy, but it becomes vastly more expensive. Unfortunately, every copy of the component is different, which is scary for CS people. Imagine if every time you created a copy of something, it was *guaranteed* to be slightly different.
So, you suggest doing something like 'unit tests'. Well, that's what they did, and that's what happened here, a unit test failed. They should be getting 15 turns, but are only getting 9. They're not sure why, so they're going to brainstorm and come up with a bunch of possibilities, discount as many as they can based on physics, design etc, and see if they can figure out what's wrong.
Perhaps it would be better if the summary included something like "a unit test failed", then the CS people would understand.
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you're obviously not an engineer. the big things are made up out of tiny things. its always* a tiny things that gets you
Not a mechanical engineer, no. I'm a network engineer. And when I build a network, I make sure to catch the "low hanging fruit" when I test things.
And when it comes to testing bolts, even with my non-mechanical engineering background, I can see that this is low hanging fruit. Will this bolt be able to turn 15 times in this configuration? I'm sure NASA would have been able to test that in their fish tank, and they probably did; with a different bolt...
Are you seriously saying that you've never tested a network device in your test lab that was supposed to be a drop-in replacement for older technology already installed in the office (which is a unique environment that's not repeated anywhere else in your organization), then had the new device fail to work when it was plugged in without having someone tweak the configuration?
And it's often the "low hanging fruit" that causes the problem when it's something out of the ordinary...like that someone had to force the port from autonegotiate to 100mbit because there's a flaky connection somewhere between the device and the core network so the autonegotiated 1000mbit connection wouldn't stay up, and building management refuses to replace the network cable.
In this case, they discovered metal filings when they unbolted the old unit, and though they sprayed them out with compressed nitrogen, there was apparently significant enough thread damage that the new bolt wouldn't go in.
A test lab tries to approximate reality, but it's hard to do a complete simulation of a component exposed to the vacuum of space with repeated and severe heat/cool cycles as it's exposed to and shaded from the sun.
I don't doubt that they tested everything right down to the exact same bolts (probably machined by the same vendor, and possibly even made from the same ingot of raw metal), but no test lab is a perfect representation of the real-world. Most spacewalk maintenance is rehearsed dozens or hundreds of times on earth before attempted in space.
Any self-respecting mechanic knows that WD-40 is next to useless for freeing seized fasteners*. You need a good penetrating oil or releasing fluid, e.g. Plusgas.
*It's also a very poor lubricant if you want something that lasts more than a couple of hours.
If God forks the Universe every time you roll a die, he'd better have a damned good memory.
If you're an electrical or computer engineer specializing in networks you should have enough experience to know that a single bent or corroded pin, or slightly non uniformly applied piece of solder can ruin you day.
If you're on site somewhere, especially somewhere remote, it's hard to know just how things will get messed up. What works in a lab is very different than after you've shipped it off some place and tried to get it to behave there.
Before you deploy a network you obviously test it in your own lab under exactly the same humidity, temperature, radiation exposure, altitude and personnel as for on site right? To what tolerance? You also test all of your backup equipment by having samples you store in exactly the way they're going to be stored at a live test sight, so you know what the probability is of something happening to them during storage?
Now we know single bit flip in an ethernet packet is just the sort of low hanging fruit of problems that we have network engineers for right? So I'm guessing you developed your own mathematically perfect CRC that you have published and that we should all use, to solve the 'low hanging fruit' of single bit flip errors? Just like a thread on nut and bolt right - you can take your perfect errorless network hardware, put in an aircraft, fly it to a remote island 12 time zones away you know you, with absolute certainty, that it will work 100% of the time? You should get a PhD and write articles about your techniques, the rest of us could really benefit from that.
Maybe you're not on the software side of things, but more hardware, say telephone twisted pair. Now as you know, the reason we twist pairs of wires is to prevent a signal on one wire from inducing a field on another. So I'm guessing you have some piece of equipment that can verify that all the twisted pair sets of wires you use are optimally twisted? What's it called?
Ok I'll stop being a snide asshole, unless I find out you're one of my former students.
You're right, that yes, good engineering is supposed to predict problems in advance and plan for them. You do as many tests as you can, and hope that you've figured out what problems will arise. Unfortunately, it doesn't always work perfectly, there's always some random error involved, that you have to cope with on the fly. On the ground I would say 'try another bolt', up in space, when you've got a dude in a space suit simple solutions become very expensive, time consuming and very risky. I used to do something very similar to network engineering as an on site guy, and problems that take 5 minutes to solve in the lab can take hours in the field. And think about the problem they're having they removed an old unit, and in doing so a bolt shaved. They don't, apparently, have spare bolts easily accessible for this. Now they have a tool that can apply more force to the bolt, but that could break the bolt, so rather than trying it (and it might work, and everyone is happy, and no news story gets posted on /.) they decide to take some time, think about it, probably test out a few scenarios on the ground, and go from there.
Notice also how they seemed to have some idea what to do when there were shavings from the bolt - they tried to blow away the pieces with nitrogen - someone planned enough to figure carrying a can of nitrogen might be useful, but I suspect that's a tricky problem with gloves on where you can risk puncturing the glove.
Trying to work in space, and to a lesser degree underwater, is very much an exercise in trying to not make things worse - even if you think you have a solution to this problem you're better to not screw it up and wreck hundreds of millions of dollars in equipment or a bolt that probably several hundred if not several thousand dollars to even get there (a single 100g bolt would cost anywhere between 400 dollars and 4000 depending on what launched it there).
> Not a mechanical engineer, no. I'm a network engineer.
So then...No, you're not an engineer.
They wouldn't have lasted 4 months on MIR, let alone a decade. That thing was held together by duct tape and lubricated by vodka. It seems the good ol' russian approach to technology applied here too: If force doesn't fix it, use more force.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Yep. I predict a whole bunch of armchair engineers telling NASA how to unscrew a bolt on a trillion dollar space station.
Duct tape, WD40, ... I think I'll skip this one.
No sig today...
Bolts are never reused in flight qualified spacecraft whether manned or unmanned because once they are used the threads become slightly deformed and do not hold as securely as the first time they're used. You can be sure this situation was tested many times with flight prototypes using identical bolts and I'm quite sure the particular bolt causing the problem was inspected quite thoroughly, but you are correct in that it would never have actually been used previously even for testing.
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But, since I do have an armchair and since I am an engineer I figure they will ultimately have to try some sort of lubricant or thread treatment, the risk of snapping off the bolt is too high.
If anybody bothers to read the article it mentions "metal shavings on one of its bolts and around the housing" when they removed the bolt and now it won't go back in again.
Looking at a few random posts it doesn't seem like anybody bothered - none of them are remotely related to the problem (ie. the thread needs cleaning).
Applying more force to a damaged thread will probably make it much, much worse. NASA is right to not force it.
Anecdote: This happened to my bike pedal. The pedal has a steel thread and the crank is aluminum. After a couple of months the aluminum gave up the ghost and the pedal fell out. I put some Araldite on the bolt and what was left of the crank thread and screwed it together. It's been fine ever since, maybe they could do that. :-)
No sig today...
Are you seriously saying that you've never tested a network device in your test lab that was supposed to be a drop-in replacement for older technology already installed in the office (which is a unique environment that's not repeated anywhere else in your organization), then had the new device fail to work when it was plugged in without having someone tweak the configuration?
For mission-critical networks, we have a lab setup which precisely emulate the production network: same ports, same software, same physical connections. The only difference is physical. In those cases, reconfiguration means someone messed up a test.
Well that's kind of the problem -- the physical environment. Equipment that works fine in test may not work in the real environment. For example, when you replace that old access switch that has a 100mbit trunk back to the core, you mean find out that the new switch that works great at 1gbit in your test lab works sporadically in the field because the building wiring is substandard can't support gig, if you pin the connection to 100mbit it works fine. (or replace the wiring if that's an option)
Or, in the case of the ISS, it means that the the test environment couldn't replicate the conditions in space (which, literally exist nowhere else on earth), which led to a damaged bolt when removing the part, and then the current difficulties with installing the new one.
I know there have been experiments that included capillary action in micro-gravity, astronauts playing with a globe of water and a straw for example. But as far as I know, all such experiments were in a pressurized, shirt sleeve environment. I'm not aware of any similar experiments with fluids in microgravity *and* vacuum.
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Have gnu, will travel.
This stubborn bolt incident may turn out to be a blessing in disguise
So far we human have been using many of the same things that we use on Earth and applying them on exotic locations, such as space
Inside the gravity well, whenever we meet with a stubborn bolt problem, we have many means to solve it - either apply lubrication to the bolt to make it easier to manage, apply brute force and get it in no matter what, or we throw away that stubborn bolt and replace it with another bolt
But on space, such options are not available, and/or not applicable
Maybe this whole thing is a blessing in disguise
Maybe, out of this experience, someone will come out with another method to affix two things tightly together, without having to rely on bolts and nuts
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There is spontaneous vacuum cold welding of materials, because there's no natural air lubricant is absent and atomic bonds tend to migrate across the interfaces. Capillary action works differently. In microgravity, without an anchor the tool operator is more likely to turn around the bolt than turn the bolt.
Bruce Perens.