3 ms·
All such satellites (incl. ISS) have 4 gyros while you only need 3, geometrically. That‘s your redundancy. You don‘t add stuff just for the fun of it but you do
by fbender 8y ago
All such satellites (incl. ISS) have 4 gyros while you only need 3, geometrically. That‘s your redundancy. You don‘t add stuff just for the fun of it but you do cost-benefit trade-offs that include e.g. weight (goes directly into launch costs) and design lifetime. And gyros need to be heavy because physics (i.e. you need counter overall mass of spacecraft).
- jve 8y agoSure. But not after the fact the satellite is ALREADY there. This was reply to: > Hmm, I think the second time the gyros needed replacing,... But as other mentioned, they had redundant set of gyros...
- fbender 8y agoYou can only replace what‘s already there, otherwise you‘d change the design (here orbital dynamics, thus attitude control system incl. all Math and software behind it) so much that you’re basically building a new one – and that was certainly not the goal of having an on-Orbit repairable satellite.