NASA Abandons Kepler Repairs, Looks To the Future 73
cylonlover writes "If NASA has anything to say about it, Kepler is down, but not out. At a press teleconference on Thursday it announced that it has abandoned efforts to repair the damaged unmanned probe, which was designed to search for extrasolar planets and is no longer steady enough to continue its hunt. But the space agency is looking into alternative missions for the spacecraft based on its remaining capabilities. 'On Aug. 8, engineers conducted a system-level performance test to evaluate Kepler's current capabilities. They determined wheel 2, which failed last year, can no longer provide the precision pointing necessary for science data collection. The spacecraft was returned to its point rest state, which is a stable configuration where Kepler uses thrusters to control its pointing with minimal fuel use.'"
Re:A partial success (Score:5, Informative)
as with most satellite missions gone wrong -- its was the gyroscope
Actually the gyroscopes lasted the original 3.5 year mission, but due to more noise than anticipated they collected less data than planned - which was why the mission was extended to 7.5 years. Now they won't be able to finish that, but that was really the backup plan failing. Oh well, not everything can be a Mars Rover exceeding all design specs by leaps and bounds.
Re:A partial success (Score:5, Informative)
To nitpick, they collected as much data as planned, but it was noisier than expected. Therefore they needed more data to bring the signal above the noise. Interestingly the source of the noise isn't Kepler, but sunspots on the stars causing fluctuations in the brightness. They'd counted on a 3.5 year mission being long enough to collect a strong enough signal by assuming sunspot noise was the same as from the Sun, but it turned out it was actually stronger.
Re:A partial success (Score:5, Informative)
Re:A partial success (Score:5, Informative)
Didn't NASA have reaction wheels go on another probe as well? The one we're sending to explore Ceres I think had reaction wheel issues as well and had to be reconfigured to run its mission on thrusters as well.
Reaction wheels a very well known concepts in spaceflight. The ISS uses them to point itself (The Control Moment Gyros) and pretty much any and all geosynchronous satellites also use reaction wheels to keep themselves pointed at earth. This is actually how they ended up recovering Galaxy 15. After several months of drifting while "zombie", the reaction wheels finally saturated (spinning as fast as they could go) causing the satellite to lose earth lock, and go into a safe mode.
Anyhow, the upside and downside is that they are relatively simple devices, and allow for very precise and stable pointing without spending a lot of fuel (you don't want your exhaust condensing on your optics in a telescope now do you?), but at the same time they're mechanical devices, and thus are more fragile than something that's purely solid state.