3 ms·
Reaction.Wheels.are vert heavy, adding too much redundancy of then make they all more prone to failure, add to rocket fuel costs, and also increase the needed f
by speeder 13y ago
Reaction.Wheels.are vert heavy, adding too much redundancy of then make they all more prone to failure, add to rocket fuel costs, and also increase the needed fuel on the ship thrusters and battery size, thus making everything even more heavy.
In short, add more reaction wheels and end with a much more heavy machine, more complex, expensive, and more expensive to launch.
- EvanKelly 13y agoI had a hunch that was the case, but this quote from Wikipedia suggests otherwise > Since the reaction wheel is a small fraction of the spacecraft's total mass... The gist from the Wikipedia article suggests momentum wheels (used in Hubble) are very heavy, but reaction wheels, not so much, due to their use for precision movement. Obviously I defer to someone that has more than a cursory Wikipedia articles breadth of knowledge on the subject. Am I misinterpreting Wikipedia, or are the reaction wheels on Keppler more than a "small fraction of the mass"?
- sbierwagen 13y agoMomentum wheels are reaction wheels. I'm not sure why the wikipedia article on them thinks differently-- Hubble wasn't gyrostablized at all, it's a telescope, it can't be allowed to spin. Hubble also masses eleven times that of Kepler. (11,000kg vs 1,000kg) I don't know the actual numbers, but attitude control systems possibly take up a larger percentage of spacecraft mass on Kepler than it does on Hubble.