ISS Gyro Fixed Via Spacewalk 143
Teahouse writes "After a failed attempt last week, the ISS Astronauts finally got to fix the external gyroscope circut breaker in the station. Tests are being run today, but it looks like the ISS is back to having attitude stability with redundancy. This is particularly significant with the Shuttle being grounded for an extended period because the ISS would have had to use thruster fuel to keep the Station's solar panels pointed in the right direction without the gyroscopes, and no guarantee when more fuel would be arriving."
Re:Attitude stability? (Score:5, Informative)
Re:how do gyros work?? (Score:5, Informative)
Re:Another space station dying of neglect? (Score:5, Informative)
Never mind the collossal risk posed by an asteroid strike. Sure, the chances of a species-killer are pretty low, but the downsides are enourmous. Better to start on contingency plans as soon as we can.
Re:Attitude stability? (Score:3, Informative)
Pedantic, yes, but perhaps useful. Or not.
Re:how do gyros work?? (Score:2, Informative)
Gyro is short for gyroscope. Did you ever play with a top as a child? Hopefully, at least once. Conceptually, a gyro is like a top; it is spun up very fast (thousands of RPM, typically), gaining a lot of angular momentum (sorry). Part of the gyro is fixed in the housing in which it resides; the rest is free to move around, typically in two axes, just like a top leans to and fro a little as it moves across a surface. The housing is mounted to the spacecraft in an orientation that aligns the gyro in a known way. When the spacecraft's attitude, or orientation, changes, the housing moves with it BUT the gyro "top" remains fixed inertially, i.e., with respect to things outside the spacecraft. Remember Newton's first law of motion? Paraphrasing, an object in motion stays in motion, maintaining it's orientation, unless something acts on it. The gyro is free to move in the housing, so its orientation remains fixed (inertially) even though the housing its in moves around it.
Anyway, electronics in the inertial reference unit, the overall package of which the gyro is a part, sense the change in orientation of the gyro with respect to the housing and convert this into rotations about the axes the gyro is aligned with. Actually, IRUs typically put out accelerations, which must be integrated to produce rotations, but the idea is the same.
Hopefully, that helped a bit.
Reasons for putting it outside (Score:5, Informative)
A couple of reasons.. (Score:3, Informative)