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Equipment Failure May Cut Kepler Mission Short

72 points by danhak 13y ago

kiba 13y ago
Given that the kepler telescope exceeds its original mission lifespan by 4 years, it's safe to say that the kepler mission is not really "cut short", more like "cannot keep going".
- breadbox 13y ago
  Kepler was launched 4 years ago, so I think your first sentence is misworded. Its original 3.5-year mission was pushed out 3 years due to issues with noisy data, so it hasn't really completed its original mission yet. (Not that it hasn't done a great deal of excellent work already, but much more is/was still to come.)
  - kiba 13y ago
    I stand corrected.
krschultz 13y ago
Very sad, this is one of the more important NASA programs at the moment.
EvanKelly 13y ago
From the article, this is the second reaction wheel to fail in 8 months. They had redundancy, but I wonder what the cost/benefit would have been to have more backup wheels. Obviously, I'm an armchair/hindsight 20/20 observer here. I have no clue whether it would have been an been an infeasible engineering feat to have more than 4 wheels. Also, I don't really have a clue what a reaction wheel is. EDIT: Wikipedia to the rescue http://en.wikipedia.org/wiki/Reaction_wheel http://en.wikipedia.org/wiki/Reaction_wheel
- mikeash 13y ago
  In your hindsight bit, don't forget to look at not just wheels but every other piece of equipment on the spacecraft. Otherwise, you're just playing a game of whack-a-mole. Add more reaction wheels, then the coolant system fails. Add redundancies there, then the computer fails. Sure, you can include twice as much of everything, but then you end up with something that's vastly more expensive.
  - Daniel_Newby 13y ago
    Reaction wheel bearings are notorious for failing, having killed numerous science spacecraft. I remain amazed that they have not standardized on magnetic bearings.
    - sbierwagen 13y ago
      Power draw?
    - BlackAura 13y ago
      It's possible that there's some engineering reason why they haven't. From a quick search and skimming a couple of research papers, it looks like magnetic bearings are used on smaller craft, but it sounds like they're still being actively developed for larger craft. I guess the tech might not have been available for use on Kepler when they were designing it (they seem to have started design work in the late '90s sometime), or it had some kind of limitation or drawback that they couldn't accept.
- 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 ago
ANH 13y ago
It's worth pointing out that they still have terabytes of data on the ground that hasn't been sifted through, so even if the spacecraft's mission isn't resurrected, we can still expect to hear about new Kepler discoveries over the next year or two.
drivebyacct2 13y ago
$600 million is nothing. Why can't we spend more on this? Do people really lack such forethought or is it the 100-yr-lifespan selfishness?
- deleted 13y ago
  [deleted]
- robryan 13y ago
  Yeah, the killer is the lead times, if it were decided right now to build a replacement it would be a long time before any results would be seen. Too bad the program wasn't devised it terms of building more than one from the start.
  - drivebyacct2 13y ago
    "Why build one when you can build two for twice the price". God I'm such a nerd.
wikiburner 13y ago
An obvious question that wasn't addressed in the article - could they manually fix it? I don't think most people remember what a punchline Hubble was immediately after its launch, until the rescue mission turned things around. Obviously, our access to space is much more limited currently, but it seems like finding a way to make it happen via the Russians or even SpaceX (depending on how quickly they can get to manned launch capability) would make a lot of sense.
- nitrogen 13y ago
  Kepler is very far away, orbiting the sun: http://en.wikipedia.org/wiki/Kepler_(spacecraft)#Spacecraft_orbit_and_orientation http://en.wikipedia.org/wiki/Kepler_(spacecraft)#Spacecraft_...
  - wikiburner 13y ago
    Yep, I'm an idiot. I was just about to update my post after doing a bit of wikipediaing. Looks like I'll have to turn down that job as head of NASA now.
  - robryan 13y ago
    I think given the cost of this mission relative to things like a space shuttle launch it would have/ still is better to build more than one. Although I can't really say too much as Australia is useless at putting any real money into space science (of the spacecraft type at least).
androidb 13y ago
The saddest news I've read today. However there's still hope that they might resurrect one of the 2 reaction wheels that are currently down so maybe they'll be able to figure that out (in the article they mention that they'll even try that with the first reaction wheel that was shut down a year ago).

72 points by danhak 13y ago

kiba 13y ago

Given that the kepler telescope exceeds its original mission lifespan by 4 years, it's safe to say that the kepler mission is not really "cut short", more like "cannot keep going".

breadbox 13y ago
Kepler was launched 4 years ago, so I think your first sentence is misworded. Its original 3.5-year mission was pushed out 3 years due to issues with noisy data, so it hasn't really completed its original mission yet. (Not that it hasn't done a great deal of excellent work already, but much more is/was still to come.)
- kiba 13y ago
  I stand corrected.

krschultz 13y ago

Very sad, this is one of the more important NASA programs at the moment.

EvanKelly 13y ago

From the article, this is the second reaction wheel to fail in 8 months. They had redundancy, but I wonder what the cost/benefit would have been to have more backup wheels. Obviously, I'm an armchair/hindsight 20/20 observer here. I have no clue whether it would have been an been an infeasible engineering feat to have more than 4 wheels. Also, I don't really have a clue what a reaction wheel is. EDIT: Wikipedia to the rescue http://en.wikipedia.org/wiki/Reaction_wheel http://en.wikipedia.org/wiki/Reaction_wheel

mikeash 13y ago
In your hindsight bit, don't forget to look at not just wheels but every other piece of equipment on the spacecraft. Otherwise, you're just playing a game of whack-a-mole. Add more reaction wheels, then the coolant system fails. Add redundancies there, then the computer fails. Sure, you can include twice as much of everything, but then you end up with something that's vastly more expensive.
- Daniel_Newby 13y ago
  Reaction wheel bearings are notorious for failing, having killed numerous science spacecraft. I remain amazed that they have not standardized on magnetic bearings.
  - sbierwagen 13y ago
    Power draw?
  - BlackAura 13y ago
    It's possible that there's some engineering reason why they haven't. From a quick search and skimming a couple of research papers, it looks like magnetic bearings are used on smaller craft, but it sounds like they're still being actively developed for larger craft. I guess the tech might not have been available for use on Kepler when they were designing it (they seem to have started design work in the late '90s sometime), or it had some kind of limitation or drawback that they couldn't accept.
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 ago

ANH 13y ago

It's worth pointing out that they still have terabytes of data on the ground that hasn't been sifted through, so even if the spacecraft's mission isn't resurrected, we can still expect to hear about new Kepler discoveries over the next year or two.

drivebyacct2 13y ago

$600 million is nothing. Why can't we spend more on this? Do people really lack such forethought or is it the 100-yr-lifespan selfishness?

deleted 13y ago
[deleted]
robryan 13y ago
Yeah, the killer is the lead times, if it were decided right now to build a replacement it would be a long time before any results would be seen. Too bad the program wasn't devised it terms of building more than one from the start.
- drivebyacct2 13y ago
  "Why build one when you can build two for twice the price". God I'm such a nerd.

wikiburner 13y ago

An obvious question that wasn't addressed in the article - could they manually fix it? I don't think most people remember what a punchline Hubble was immediately after its launch, until the rescue mission turned things around. Obviously, our access to space is much more limited currently, but it seems like finding a way to make it happen via the Russians or even SpaceX (depending on how quickly they can get to manned launch capability) would make a lot of sense.

nitrogen 13y ago
Kepler is very far away, orbiting the sun: http://en.wikipedia.org/wiki/Kepler_(spacecraft)#Spacecraft_orbit_and_orientation http://en.wikipedia.org/wiki/Kepler_(spacecraft)#Spacecraft_...
- wikiburner 13y ago
  Yep, I'm an idiot. I was just about to update my post after doing a bit of wikipediaing. Looks like I'll have to turn down that job as head of NASA now.
- robryan 13y ago
  I think given the cost of this mission relative to things like a space shuttle launch it would have/ still is better to build more than one. Although I can't really say too much as Australia is useless at putting any real money into space science (of the spacecraft type at least).

androidb 13y ago

The saddest news I've read today. However there's still hope that they might resurrect one of the 2 reaction wheels that are currently down so maybe they'll be able to figure that out (in the article they mention that they'll even try that with the first reaction wheel that was shut down a year ago).