Equipment Failure May Cut Kepler Mission Short 76
HyperbolicParabaloid writes "According to the New York Times, an equipment failure on the Kepler spacecraft may mean the end of its planet-hunting mission. One of the reaction wheels that maintains the craft's orientation — critical to long-exposure imaging — has failed. 'In January engineers noticed that one of the reaction wheels that keep the spacecraft pointed was experiencing too much friction. They shut the spacecraft down for a couple of weeks to give it a rest, in the hopes that the wheel’s lubricant would spread out and solve the problem. But when they turned it back on, the friction was still there. Until now, the problem had not interfered with observations, which are scheduled to go on until at least 2016. Kepler was launched with four reaction wheels, but one failed last year after showing signs of erratic friction. Three wheels are required to keep Kepler properly and precisely aimed. Loss of the wheel has robbed it of the ability to detect Earth-size planets, although project managers hope to remedy the situation. The odds, astronomers said, are less than 50-50.'"
Futurama (Score:5, Funny)
Obvious Futurama response:
http://www.youtube.com/watch?v=1Isjgc0oX0s [youtube.com]
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I'm sorry, it's incredibly difficult to understand what you're saying when you have your head buried in your rectum.
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Another Slashtard
It's usual to put your sig at the end of your posts.
Jokes aside (Score:1)
50/50? (Score:1)
Surely the odds are astronomical?
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Poor guy (Score:5, Funny)
Re:so much for... (Score:4, Informative)
Maybe you missed the part where it mentioned the fact that they -had- redundancy, and that one had also failed?
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one reaction wheel failed and they lost a primary mission objective... where's the redundancy in that?
so what if there were four wheels... if it only takes one to fail and kill the mission, then that one is a single point of failure and the other three aren't redundancies for that critical one.
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Kepler was launched with four reaction wheels, but one failed last year after showing signs of erratic friction. Three wheels are required to keep Kepler properly and precisely aimed, and now there are only two.
There you go.
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From the Slashdot summary:
One of the reaction wheels that maintains the craft's orientation — critical to long-exposure imaging — has failed.
Kepler was launched with four reaction wheels, but one failed last year after showing signs of erratic friction. Three wheels are required to keep Kepler properly and precisely aimed. Loss of the wheel has robbed it of the ability to detect Earth-size planets, although project managers hope to remedy the situation.
No mention of two anything.
Your quote is from the TFA (which I usually don't bother reading).
Still seems as though if they can lose two wheels out of four in a single mission, with three wheels required, any reliability engineer would tell you that the level of redundancy is insufficient.
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The mission was supposed to last until 2013 so the wheels lasted as long as they were supposed to. The problem is other components did not work as initially predicted so the mission did not produce as many results as they hoped to.
Re:so much for... (Score:5, Interesting)
So we, as a species, should stop looking towards the stars and keep our noses to the ground and dig, dig until we build utopia on planet Earth? Somehow I do not think that is a long-term survival prospect for our species.
[insert link to graph showing NASA's budget as compared to DoD budget and other government agencies' budgets].
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If that isn't the finest example of short-sighted thinking, I don't know what is. What you're suggesting is we wait until the last possible second to explore what might be out there just because NASA's budget represents a fraction of a percent of the overall national budget.
If you're that concerned about Federal spending, we can cut the military by 50%, stop all subsidi
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If that isn't the finest example of short-sighted thinking, I don't know what is. What you're suggesting is we wait until the last possible second to explore what might be out there just because NASA's budget represents a fraction of a percent of the overall national budget.
Not really. I'm just highlighting that America's budget is so far down the toilet that fixing it should take priority over making it worse.
America should cut military spending... by 80%, and all subsidies should be stopped.
If the Slashdot article was about a defense issue, I would have raised the issue of defense spending. The story in this case was about space, so I highlighted how much of a waste of taxpayer money NASA is at the moment. If NASA was doing anything that benefited average Americans I would b
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inventions that came out of the space race weren't due to the "space race"... they were because of huge R&D investments made by government during a cold war with Russia, and American taxpayers probably still haven't broken even from R&D investment in the mid 1900's.
The space race was merely a front for ridiculous unwarranted missile and spy satellite R&D.
if we started moving populations into space
The United States doesn't even have it's own regular access to Low Earth Orbit... humanity is decades away from making space stations beyond th
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You are an idiot if you really believe what you read by Reuters.
Even the CPI numbers are cooked. Maybe instead of reading Reuters (where do you think Fox gets its stories?) you should listen to Peter Schiff and Ron Paul, who have predicted recent events. A lot of people seem to think that Peter is wrong on the dollar collapse simply because he refuses to nail it down to a specific time, but it will happen soon enough. Keynesians are fools... always have been.
Keep chugging your mainstream media kool aid.
$17
Replacements (Score:5, Informative)
Worry not! NASA's TESS and ESA's Gaia missions will be there to pick up the slack. Gaia launches this year and TESS in 2017.
Re:Replacements (Score:5, Informative)
There is also ESA's CHEOPS [esa.int], a planet finder, also intended for launch in 2017.
Re:Karma (Score:5, Informative)
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They might be, but it wouldn't matter. The friction is probably due to ice forming on the reaction wheel or its axle. Ice will eventually clog up even a mag-lev system. Space is just a difficult place to keep mechanisms working.
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To be fair, NASA already "burned" quite a bit of karma on previous Mars missions. It just seems like the last few have been exceptionally successful in comparison.
Primary mission already over (Score:5, Informative)
It's the extended mission (to 2016) that may be cut short. The primary mission is already over, in 2012.
They still have 2 reaction wheels, and also thrusters, and a fair amount of fuel. In the press release [nasa.gov] there was a discussion of options, which "are likely to include steps to attempt to recover wheel functionality and to investigate the utility of a hybrid mode, using both wheels and thrusters."
My guess is that, if they cannot recover pointed mode, they will put the spacecraft in a slow roll, which (if it is slow enough) would be good enough to detect hot Jupiters, but not Earth-like planets.
Re:Primary mission already over (Score:5, Interesting)
'It's the extended mission (to 2016) that may be cut short. The primary mission is already over, in 2012' - this is true, and somewhat false.
One of the things that was discovered early on was that the sun was not a sun-like star.
It is unusually quiet - with little variation in brightness. Most of the population of stars observed by Kepler turn out to be lots noisier.
This unfortunately made the primary mission - which was to detect earth like planets in earth like orbits - not achievable in the original timescale.
With an extended mission, you can dig through more data, and get enough signal from multiple planet crossings to bring it up out of the noise, getting you back to where you would have been had the original mission assumptions been correct.
Unfortunately, the wheel failure seems to have constrained this.
At best the degraded pointing mode they may end up in will have much more noise in the signal, making it much less useful for many purposes.
(It will likely still be able to detect very large far out planets)
Another unfortunate fact is that the data from the cameras is very 'cooked' onboard - most of the data is thrown away automatically. This would make doing clever things to fix the problem in software on the returned data hard. How flexible the on-craft pipeline is is an interesting question.
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Another unfortunate fact is that the data from the cameras is very 'cooked' onboard - most of the data is thrown away automatically. This would make doing clever things to fix the problem in software on the returned data hard. How flexible the on-craft pipeline is is an interesting question.
The data from the CCDs is not "cooked" very much at all. See http://arxiv.org/abs/1001.0258 There is no on-board pipeline. It's just that only 5% of the pixels are saved for downloading. With the spacecraft not at fine point this means the light from each star gets spread out to more pixles. This means more pixels per target star and therefore fewer targets.
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Be that as it may, the hardware was only designed to last till the expected mission end - which it did - so you can't really complain about it not lasting till 2016
Re:Repurpose? (Score:2)
Is there some other way to use this instrument in it's hobbled state? Lunar mapping? Asteroid hunting? Etc...?? Would be nice to salvage the hardware, even if the primary mission is toasted.
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Too little redundancy... (Score:2)
It has plenty (Score:5, Informative)
"Malfunction" my ass! (Score:2)
The reptoids will stop at nothing to prevent humans from finding their homeworld!
But seriously, bummer. Many years ago (1997!) I went to a NASA Ames / Moffet Field open house. Various working groups had set up displays showing the mission concepts they were working on. One of these was Kepler.
reaction Wheels strike again (Score:2)
Is it me, or do reaction wheels seem to be the most failure prone part of space telescopes?
Re:reaction Wheels strike again (Score:4, Insightful)
It's one of the only moving parts.
It also has something to do with the fact that something with (relatively) little mass has to spin at a bonkers rate to generate the reaction force required.
Remember Hubble? (Score:2)
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kepler is in an earth trailing orbit, 6 million miles away, we can get to it
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Aliens! (Score:1)
Universal troubleshooting methodology (Score:1)
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They shut the spacecraft down for a couple of weeks to give it a rest, in the hopes that the wheel’s lubricant would spread out and solve the problem. But when they turned it back on, the friction was still there.
Obvious Solution (Score:1)
Just send the space shuttle up to fix it.
Oh wait...
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The shuttle was nowhere near capable of flying to Kepler. It's at 40 million miles, while the space shuttle could only fly up a couple hundred miles. Besides, considering the cost of the mission, it would not warrant a complicated repair mission. For that money you could probably send up 10 new telescopes.
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If I remember right, there already is a successor in the pipeline. Anyway, I would be surprised that the end of Kepler would be the end of the exoplanet revolution. It's a very hot field in astronomy. There's a scientific gold vein out there, people will keep digging. Kepler is a significant milestone, and one of my favorite missions, but not a unique instrument. It's the beginning, not the end.
Well we fixed Hubble (Score:1)
What is it with momentum wheels, anyway? (Score:3)
These seem to be a relatively common source of woe for spacecraft that use them. I understand it's moving parts and all that, but surely in 0-G there can't be *that* much wear on bearings. Anyway, there seems to be plenty of work on magnetic bearings for momentum wheels, which would eliminate mechanical wear. Or is it not the bearings that fail? Can any /. readers shed some light on why these things seem to pack it in so frequently?
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Thanks, your comment is interesting. True, the spacecraft rotational inertia is put on the momentum wheel bearings when they're used to reorient the spacecraft. The force exerted on the bearings should be proportional to the slew rate - faster slew, more force. You'd think a mission like Kepler would have mainly very small slew rates (high pointing accuracy = low angular excursion rates). Vacuum effects on lubricants, for sure. Does anybody use magnetic bearings on spacecraft momentum wheels? Particularly f
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You'd also think they's have these attached to the spafe station for many years, so they could study wear and tear on it.
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The problem might not be wear and tear, it might be ice forming somewhere in the wheel system. Normal ice can be evaporated away by heating up the instrument, but when I say 'ice', I mean deposits of some material -- vaporized rubber, outgassing paint, or even neutron spalling. All of those could add friction to the system, can't be easily removed, and may have nothing to do with the bearings.
TODO list (Score:4, Insightful)
- Make better reaction wheels
- Make better valves
Those two things always come back when missions end, or when a rocket launch has to be delayed.