International Space Station Gyroscope Fails

b00m3rang writes "Reuters reports that one of the three working gyroscopes that keep the international space station stable and in the right position stopped working, just hours after a new two-man crew moved in for a half-year stay."

Comments

just a spacewalk

[qewl]

All they need to do is a spacewalk out and restart it.

He stressed, however, "We're not dealing with a safety issue," and added it would take several weeks to determine when to schedule the spacewalk.

There are two gyroscopes still functioning, and that is enough to stabilize the station, Suffredini said. If one of these remaining gyroscopes fails, the station will rely on thrusters to keep it steady.

Too bad they can't do that for Hubble too.

Re:just a spacewalk

[Derf the]

Can anyone tell us why it takes 2 weeks to schedule the spacewalk?

If it was an imminent emergency, how short a time before they could get out there? Minetes, hours, days?

Re:just a spacewalk

[angusr]

"There are two gyroscopes still functioning, and that is enough to stabilize the station, Suffredini said. If one of these remaining gyroscopes fails, the station will rely on thrusters to keep it steady."

Too bad they can't do that for Hubble too.

No thrusters on Hubble, of course.

It wouldn't work for Hubble anyway - thrusters are a fairly coarse method of control, resulting it lots of banging and vibration. While on the ISS that would be fine (although some mu-g experiments would probably be upset) on Hubble it would render it unusable until the vibrations have died down after every thrust. Plus, of course, while observations take place they couldn't use the thrusters - and hence the lack of control is going to make those observations pretty hopeless anyway.

If the robot mission to attach a gyro pack to Hubble goes ahead (which I hope it does) then it is likely to have thrusters on it - however, I would suspect that they're not for day-to-day control but to control Hubble when it's re-entered.

I shouldn't laugh...

[John Seminal]

"The gyroscope problem stemmed from an underlying failure in a circuit breaker.... At this time, the box that holds that particular circuit breaker ... is outside (the station)".

I wonder why they would place the circuit breakers outside the space station. If those ciruit breakers are like anything in my house, they go out all the time. Or maybe it is just my power company with all the brown outs in the summer.

I'm glad the story says this is not a critical system or a threat to the astronauts. Still, I wonder why the circuit breaker is not in a place easy to get to.

This gives me another idea. I wonder if they have a special escape pod attached to the space station, so if some critical system goes, they can escape.

Re:I shouldn't laugh...

[tiger99]

And weight (of wiring etc) is probably one of the main reasons why the breakers are outside (might be to minimise the length between source and load), the other probably being that you would not want the wiring on the unprotected side of the breaker inside, because of what would happen if it shorted. At the very least, unpleasant smoke and fumes, possibly fire. Virtually every cable insulation will, given sufficient energy, burn or emit toxic fumes. The exceptions may be glass and ceramic, not really practicable.

And before anyone mentions PTFE (Teflon), well it may be OK in a frying pan, but a wiring fault would result in the release of fluorine gas, which would resct with moisture in the air to give hydrofluoric acid. Not good. A frying pan fire could presumably be very serious if the temperature got too high, IIRC about 400 deg C. If you inhale hydrofluoric acid, or get a small amount on the skin, you usually die, fairly unpleasantly. Someone who went to school with me died that way, many years ago, age about 22, from a small skin splash of HF even though it was quickly washed off.

Teflon has been, and probably still is, used in unmanned satellites, OK in the smaller ones where a total loss is not an absolute disaster, but I think it would be frowned upon in things which earn serious money and have to keep working, such as comms sattelites. There will be Teflon bits in the microwave equipment, and in some mechanisms, which can't otherwise be lubricated, but not necessarily on normal wiring.

I don't know what kind of wire NASA currently use, the aerospace industry has been through a variety. At one time, Kapton seemed good, we now know that it is lethal in circuits which have sufficient energy to initiate arcing.

BTW, Kapton and Teflon are OK where there is always insufficient energy available to seriously raise the temperature, in fact I like working with Teflon in particular, but only in the right place.