lpetrich
Contributor
NASA put its famous planet-hunting telescope to sleep because it’s almost out of fuel - The Verge noting NASA’s Kepler Spacecraft Pauses Science Observations | NASA
Like many other spacecraft, the Kepler spacecraft orients itself with miniature rockets, and Kepler's ones use a common fuel for such rockets: hydrazine. These rockets use hydrazine by decomposing it with a catalyst.
Also like many other spacecraft, the Kepler one also uses reaction wheels to orient itself. The spacecraft spins them in the opposite direction to how it wants to turn, and conservation of angular momentum does the rest. Kepler originally had four of them, but after three years of observing, two of them failed. That ended Kepler's original mission of observing a patch of sky between stars Deneb and Vega, but the spacecraft's controllers got it into an extended mission, K2. It involves using the Sun's shining on it to stabilize the spacecraft, and the spacecraft has been observing patches of sky on the ecliptic, the plane of the Earth's orbit around the Sun.
But every now and then, Kepler must be reoriented to upload its data to the Deep Space Network of radiotelescopes, and that requires some of its fuel.
The spacecraft is apparently running very low on fuel, so its controllers have decided to stop observations until early August, when the spacecraft has some time reserved for it at the Deep Space Network. Then it will be reoriented to upload its most recent data, and if that succeeds, then it will be reoriented for its next observing run.
Like many other spacecraft, the Kepler spacecraft orients itself with miniature rockets, and Kepler's ones use a common fuel for such rockets: hydrazine. These rockets use hydrazine by decomposing it with a catalyst.
Also like many other spacecraft, the Kepler one also uses reaction wheels to orient itself. The spacecraft spins them in the opposite direction to how it wants to turn, and conservation of angular momentum does the rest. Kepler originally had four of them, but after three years of observing, two of them failed. That ended Kepler's original mission of observing a patch of sky between stars Deneb and Vega, but the spacecraft's controllers got it into an extended mission, K2. It involves using the Sun's shining on it to stabilize the spacecraft, and the spacecraft has been observing patches of sky on the ecliptic, the plane of the Earth's orbit around the Sun.
But every now and then, Kepler must be reoriented to upload its data to the Deep Space Network of radiotelescopes, and that requires some of its fuel.
The spacecraft is apparently running very low on fuel, so its controllers have decided to stop observations until early August, when the spacecraft has some time reserved for it at the Deep Space Network. Then it will be reoriented to upload its most recent data, and if that succeeds, then it will be reoriented for its next observing run.
