So what kind of redundancy does Kepler have for its reaction wheel system?Is there a potential case for adding more redundancy for this in future similar spacecraft?
Quote from: sanman on 05/15/2013 09:34 pmSo what kind of redundancy does Kepler have for its reaction wheel system?Is there a potential case for adding more redundancy for this in future similar spacecraft?It has redundancy. It already surpassed its design life.
AFAIK, these reaction wheels are pretty bulky, so as far as redundancy goes they put in just one spare, which in this case bought them a year of extra time.
You can always make the case for more wheels/more redundancy but in the end there's a number of constraints. Cost, schedule, weight, complexity, reliability.
A better approach for future spacecraft would probably be to learn what happened to these reaction wheels and make future ones more reliable.
AFAIK, these reaction wheels are pretty bulky, so as far as redundancy goes they put in just one spare, which in this case bought them a year of extra time.You can always make the case for more wheels/more redundancy but in the end there's a number of constraints. Cost, schedule, weight, complexity, reliability. A better approach for future spacecraft would probably be to learn what happened to these reaction wheels and make future ones more reliable.
Quote from: Jim on 05/15/2013 10:32 pmQuote from: sanman on 05/15/2013 09:34 pmSo what kind of redundancy does Kepler have for its reaction wheel system?Is there a potential case for adding more redundancy for this in future similar spacecraft?It has redundancy. It already surpassed its design life.I think Opportunity's design-life exceedance ratio has us spoiled!
If this is the end of the road for Kepler's planet hunting mission, at least the craft discovered Kepler 62e and 62f before the gyro gave out. Kepler did a great job, opened a new frontier of exploration. Hoping TESS and other missions can discover a true earth analog soon!
I wonder if the team can potentially calibrate multiple pixels around each target star to give them close to the same photometric accuracy while relying on less accurate pointing, albeit with more data processing being necessary. If I understand right, the processing to do this would have to take place aboard Kepler, due to bandwidth constraints.
There is still Kepler data in the science pipeline!
Kepler isn't done giving us discoveries, it will be many years of discoveries from the data set that it has returned.
Quote from: Nickolai on 05/15/2013 09:48 pmAFAIK, these reaction wheels are pretty bulky, so as far as redundancy goes they put in just one spare, which in this case bought them a year of extra time.You can always make the case for more wheels/more redundancy but in the end there's a number of constraints. Cost, schedule, weight, complexity, reliability. A better approach for future spacecraft would probably be to learn what happened to these reaction wheels and make future ones more reliable.These were reliable enough. It exceeded the design life. There ones with longer design lives, just more expensive.
Not as silly as it sounds. Got some decent scientists on.
Quote from: Jim on 05/15/2013 11:04 pmQuote from: Nickolai on 05/15/2013 09:48 pmAFAIK, these reaction wheels are pretty bulky, so as far as redundancy goes they put in just one spare, which in this case bought them a year of extra time.You can always make the case for more wheels/more redundancy but in the end there's a number of constraints. Cost, schedule, weight, complexity, reliability. A better approach for future spacecraft would probably be to learn what happened to these reaction wheels and make future ones more reliable.These were reliable enough. It exceeded the design life. There ones with longer design lives, just more expensive.Jim, what sums we are talking about here?
If you're in the UK, there's a pretty decent show on Channel 5 about Kepler's findings and what potential aliens would look like if they were on those planets.Not as silly as it sounds. Got some decent scientists on.
I was trying to figure the odds of Kepler recovery. So it does not look good for Kepler.
Quote from: LouScheffer on 05/24/2013 02:26 amI was trying to figure the odds of Kepler recovery. So it does not look good for Kepler. I'm highly constrained with respect to what I can say (vs. what I'd really like to say about those wheels)... Read this:http://www.nature.com/news/the-wheels-come-off-kepler-1.13032