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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.
Just hammer it in with a crescent wrench.. what's the matter with these people?
“He’s not deformed, he’s just drunk!”
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.
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.
Please consider this account deleted, I just can't be bothered with the spam anymore.
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.
Help I am stuck in a signature factory!
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...