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NASA Abandons Kepler Repairs, Looks To the Future

Posted by Soulskill on from the time-to-crash-it-into-planet-genesis dept.

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.'"

73 comments

  1. A partial success by Anonymous Coward · · Score: 3, Interesting

    It was supposed to have a 3.5 year mission. It appears that it might have come pretty close to that, but it didn't get nearly the data it was supposed to. This is pretty disappointing and they should probably hold a formal design review to determine what went wrong in the design and construction and determine if a replacement should be built to finally accomplish the mission that was planned.

    1. Re:A partial success by ackthpt · · Score: 1

      It was supposed to have a 3.5 year mission. It appears that it might have come pretty close to that, but it didn't get nearly the data it was supposed to. This is pretty disappointing and they should probably hold a formal design review to determine what went wrong in the design and construction and determine if a replacement should be built to finally accomplish the mission that was planned.

      You're talking a lot of sense there. We learn from our mistakes. Here's an opportunity to learn.

      --

      A feeling of having made the same mistake before: Deja Foobar
    2. Re:A partial success by rraylion · · Score: 5, Interesting

      as with most satellite missions gone wrong -- its was the gyroscope.... remember it was replaced on Hubble a few times... its seems to be the weakest link in a lot of missions as it has to be a moving part to induce counter rotation in the satellite. it's only feasible to put so many on board ... so maybe a redesign of this one part will save future missions ... but maybe its time to think outside the box now that we know ion drives work a kg of propellant and three exhuast ports would fix this issue with new tech

      Other than that it was an awesome mission.

    3. Re:A partial success by Anonymous Coward · · Score: 0

      At the same time, though, as someone who doesn't follow NASA very closely, NASA missions have a reputation of lasting far, far beyond their technical limits, and a mission failing to live up to its advertised lifetime is unheard of.

    4. Re:A partial success by Kjella · · 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.

      --
      Live today, because you never know what tomorrow brings
    5. Re:A partial success by Electricity+Likes+Me · · Score: 2

      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.

      It certainly seems like this is probably going to be a big engineering challenge into the future since super-steady stargazing probes are hardly going out of fashion. Though I suppose the better issue is "can we make some of this stuff replaceable/repairable cost effectively?"

    6. Re:A partial success by Sockatume · · Score: 4, 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.

      --
      No kidding!!! What do you say at this point?
    7. Re:A partial success by Yoda222 · · Score: 4, Informative

      You can control attitude using (ion) thruster, but reaction wheels have some advantages. One of the biggest advantage of RWs is that it's (close to) a linear actuator (outside of the zero crossing zone), where thruster are bang bang actuators. In fact they are bad bang bang actuator, because you have some transient at start and end of the pulse.

    8. Re:A partial success by cusco · · Score: 2

      What went wrong with the design? Congress and The Office Of Management and Budget (aka TOMB), probably. That seems to be the issue with pretty much every problem we ever encounter in the space program. When lawyers and accountants get to decide that they know how to design spacecraft better than rocket scientists trouble is pretty much guaranteed. What do you want to bet that another layer of redundancy had to be eliminated because of budgetary concerns?

      --
      "Think about how stupid the average person is. Now, realise that half of them are dumber than that." - George Carlin
    9. Re:A partial success by Strider- · · 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.

      --
      ...si hoc legere nimium eruditionis habes...
    10. Re:A partial success by Anonymous Coward · · Score: 4, Funny

      Given how common this mode of failure is, throwing a lot of money into the study of better reaction wheel designs would probably pay off for a slew of future missions.

      [I can't believe I just said that]

    11. Re:A partial success by K.+S.+Kyosuke · · Score: 1

      as with most satellite missions gone wrong -- its was the gyroscope.... remember it was replaced on Hubble a few times... its seems to be the weakest link in a lot of missions as it has to be a moving part to induce counter rotation in the satellite.

      I wonder why they aren't using gyros with magnetic bearings. Especially in micro-gravity, that could help quite a lot.

      --
      Ezekiel 23:20
    12. Re:A partial success by fuzzyfuzzyfungus · · Score: 1

      Do you know what sort of bearing/contact point they use for a gyro that is supposed to perform reliably for multiple years, at alarming temperatures, in the vacuum of space? Is there some bearing material or lubricant that actually works under those conditions, or do they run the gyros in a gas-filled and temperature controlled module so that more conventional techniques can be used?

    13. Re:A partial success by notanalien_justgreen · · Score: 1

      Actually it lasted for the 3.5 years it was supposed to. The mission was extended to 2016 or something like that before this failure. If this was the military no one would think twice about it and they'd just launch another as they'd probably have built two anyway (hey, why let tax payers know the military has too much money?). Unfortunately it's NASA and with their tiny budget every event (even a mission failing AFTER it's designed lifetime) has massive repercussions on their budget.

    14. Re:A partial success by WindBourne · · Score: 1

      let's hope so. However, much of these issues are normally tied to lack of funding. And I do not see CONgress learning from it.

      --
      I prefer the "u" in honour as it seems to be missing these days.
    15. Re:A partial success by dpidcoe · · Score: 1

      I wonder why they aren't using gyros with magnetic bearings. Especially in micro-gravity, that could help quite a lot.

      I was going to say the same thing (though for all I know maybe they are using magnetic bearings).

      There's also some new R&D being done with active magnetic bearing control, basically you monitor the position of the shaft inside the bearing and apply changes to the magnetic field in order to dampen vibration and ensure the shaft stays centered.

    16. Re:A partial success by NEDHead · · Score: 1

      I believe that what you are referring to is actually the 'Biggity Boom Boom Clunk" actuator.

    17. Re:A partial success by Anonymous Coward · · Score: 0

      What failed was a reaction wheel, not a gyroscope.

    18. Re:A partial success by photonic · · Score: 1

      That was my thought too, but apparently they do exist already with magnetic bearings, for example this one. But problems with gyros/reaction wheels seem an old problem, wasn't Hubble stranded once for a few months with not enough gyros?

      --
      karma police: arrest this man, he talks in maths; he buzzes like a fridge, he's like a detuned radio. [radiohead]
    19. Re:A partial success by WheezyJoe · · Score: 1

      let's hope so. However, much of these issues are normally tied to lack of funding. And I do not see CONgress learning from it.

      Fixing CONgress is easy... stop electing idiots (ok, ok, easier said than done, but keep in mind, 2014 coming up).

      --
      Take it easy, Charlie, I've got an Angle...
    20. Re:A partial success by Anonymous Coward · · Score: 0

      What went wrong was the parts were made in China..

    21. Re:A partial success by ShanghaiBill · · Score: 0

      However, much of these issues are normally tied to lack of funding. And I do not see CONgress learning from it.

      Or maybe Congress is learning. NASA has a long history of low-balling estimates, and then latter coming back to Congress with massive overruns. They weren't allowed to get away with that with Kepler. NASA needs to learn how to manage a budget.

    22. Re:A partial success by Anonymous Coward · · Score: 0

      This may be a myth, but...

      supposedly the "best source" for amazing quality and precision ball bearings for gyros used to be the same manufacturers as for VHS recording heads which needed extremely precision high velocity spinning.
      (rumor has it that various countries imported and disassembled Japanese VCRs to use the bearings in their ICBM missiles)

      I could imagine that with the decline in VCR demand the source of high quality gyro bearings dried up.

    23. Re:A partial success by camperdave · · Score: 1

      No. That's the failure mode of a reaction wheel. A thruster is somewhere between "Ack!" and "Thbbft!"

      --
      When our name is on the back of your car, we're behind you all the way!
    24. Re:A partial success by tibit · · Score: 1

      I think that in the future the only option for gyros, barring new bearing material discoveries, would be fully non-contact operation with magnetic levitation bearings, operating in vacuum. Right now I think the gyros are at least temperature-conditioned, but yeah, the bearings are still a problem.

      --
      A successful API design takes a mixture of software design and pedagogy.
    25. Re:A partial success by cusco · · Score: 1

      Don't know for sure, but I'd be surprised if things like solar storms couldn't upset magnetic bearings. Also, having a really strong magnetic field nearby can perturb readings on some of the more delicate instruments.

      --
      "Think about how stupid the average person is. Now, realise that half of them are dumber than that." - George Carlin
    26. Re:A partial success by Brett+Buck · · Score: 1

      It is not the gyroscope. The problem was with reaction wheels. Any gyroscopic effect they have is an unwanted side effect in most cases.

            Brett

    27. Re:A partial success by Anonymous Coward · · Score: 0

      they should probably hold a formal design review to determine what went wrong in the design and construction and determine if a replacement should be built to finally accomplish the mission that was planned.

      What do you expect when the lowest bid wins the contract?

    28. Re:A partial success by DerekLyons · · Score: 1

      maybe its time to think outside the box now that we know ion drives work a kg of propellant and three exhuast ports would fix this issue with new tech

      Not only will ion drives not work in this situation (insufficient thrust, insufficient fine throttle control), they have the disadvantage of potentially contaminating the optics with their exhaust. As with Hubble, the later is a huge concern and why they chose reaction wheels in the first place. (Not to mention not requiring potentially mission limiting consumables.)

    29. Re:A partial success by Strider- · · Score: 1

      I wonder why they aren't using gyros with magnetic bearings. Especially in micro-gravity, that could help quite a lot.

      We aren't talking about small sensor type devices here. (Attitude sensing is done with laser ring gyros, no moving parts) Reaction wheels are rather large objects and can provide significant force to orient the spacecraft.

      --
      ...si hoc legere nimium eruditionis habes...
    30. Re:A partial success by Anonymous Coward · · Score: 0

      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.

      Sunspots correlate with stellar activity like coronal mass ejections. That has implications for both the habitability of planet bearing stars and the technologies a civilization around them can develop.

      Not good to discover electricity by discovering that certain metal deposits become randomly charged, magnetized and demagnetized without explanation to your pre-industrial-age astronomy.

      And that any useful length of cable melts down or that 1/2 the year you can't use radio.

    31. Re:A partial success by Firethorn · · Score: 2

      At least part of the reason for the extra expenses is that Congress will often starve the projects of money over the years, forcing NASA to work slower - and as it costs money to simply 'keep the lights on', it results in overruns. Then there's the whole 'part of it has to be built in MY district', etc...

      A program that might cost $5M to build and launch a satellite over 3 years might coast $10M to do the same over 10 years.

      --
      I don't read AC A human right
    32. Re:A partial success by K.+S.+Kyosuke · · Score: 1

      I know what they are and what they do, although your "rather large" feels like a rather relative term to me. My question still stands. In near-0g, on board of an astronomical satellite or probe, in the absence of sudden large forces and movements, why wouldn't active magnetic bearings be a viable choice if ordinary bearings seem to pose problems?

      --
      Ezekiel 23:20
    33. Re:A partial success by Yoda222 · · Score: 1
      You are right, but it's TFA (first link, NASA press release) which says

      Two of Kepler's four gyroscope-like reaction wheels

      which is an inaccurate description of reaction wheels.

      (for those interested, in short : you can use a RWA (A is for Assembly) to provide gyroscopic stiffness to a spacecraft (in that case you could maybe speak of gyroscope-like). But you can also use the RWA for 3 axis pointing (precise pointing, not just gyroscopic stability) in that case it's not a gyroscope. You just transfer angular momentum from the spacecraft to the wheels. The three axis pointing could still include gyroscopic stiffness from the wheel, but it's not only that)(I know, I use too many parenthesis)

    34. Re:A partial success by Sockatume · · Score: 1

      You'd have to develop a technology based around principles other than electromagnetism. If we find a biotech civilisation, it'll be around a very active star.

      --
      No kidding!!! What do you say at this point?
  2. Heard about this on NPR by ACK!! · · Score: 4, Interesting

    It seems that NASA is challenging the scientific community to come up with new projects or experiments that could still work despite the Kepler's limitations now. So it is time for all the scientists with their eyes toward the sky to start dusting off the keyboards and to come up with some cool new proposals. So even though it was not a screaming success the project could still turn out to be important to the scientific community going forward. If we have some scientists who can come up with neat ideas on how to use the capabilities this device still has.

    --
    ACK /ak/ interj. 2. [from the comic strip "Bloom County"] An exclamation of surprised disgust, esp. i
    1. Re:Heard about this on NPR by steelfood · · Score: 2

      Data collection may have ended, but the analysis has certainly not. We can't gauge the success of the mission to any degree of accuracy until all the data is analyzed. It's been enormously successful thus far in finding exoplanets, but the unanalyzed data may yet yield greater discoveries.

      And even data collection may still be possible. There is mention of using software to do the correction, rather than relying on hardware. I don't know how feasible this would be when most stars are a few pixels wide at the most, but it'd nonetheless be interesting to see what comes out of this idea.

      --
      "If a nation expects to be ignorant and free in a state of civilization, it expects what never was and never will be."
    2. Re:Heard about this on NPR by notanalien_justgreen · · Score: 1

      To be fair, the project lasted as long as it's primary lifetime was scheduled (3.5 years). The only reason it wasn't 100% successful is that stars are apparently noisier than our sun, so it requires longer exposures to beat down the noise. This wasn't a failure - it was just an unforeseen issue with reality.

    3. Re:Heard about this on NPR by ppanon · · Score: 1

      The only reason it wasn't 100% successful is that stars are apparently noisier than our sun

      Hmm. I do wonder how stars are "noisier". Is it at the source or due to interference from interstellar gas and the Oort Cloud? If the former, then does it have implications for the Drake equation?

      --
      Laissez lire, et laissez danser; ces deux amusements ne feront jamais de mal au monde. - Voltaire
    4. Re:Heard about this on NPR by marcosdumay · · Score: 1

      The have more and bigger spots, and have more variance in their total luminosity. It's not interference, the stars themselves are noisy.

      --
      Rethinking email
    5. Re:Heard about this on NPR by slick7 · · Score: 1

      They found something that really scares them and if they ignore it maybe it will go away.

      --
      The mind conceives, the body achieves, the spirit manifests.
    6. Re: Heard about this on NPR by Anonymous Coward · · Score: 0

      no, the drake equation, like most modern physics is made up stuff.

    7. Re:Heard about this on NPR by ppanon · · Score: 1

      Thanks for the informative response. Then it could affect the factors in the Drake equation. If the Sun is somehow more stable than most other stars, that could have an impact on the stability of the habitable zone and the ability of life to develop to sufficient complexity to develop intelligence.

      --
      Laissez lire, et laissez danser; ces deux amusements ne feront jamais de mal au monde. - Voltaire
    8. Re:Heard about this on NPR by Anonymous Coward · · Score: 0

      Exactly. And that in itself is another observation from Kepler, so, like most scientific experiments, even when something goes "wrong" it turns out to be interesting.

    9. Re: Heard about this on NPR by Anonymous Coward · · Score: 0

      Go play with your other toys. The adults are talking.

  3. 2 gyroscopes left... by Anonymous Coward · · Score: 1

    You can point to any angle with only two axis of rotation. Wont be as precise, but should be better than using the thruster.

    1. Re:2 gyroscopes left... by Sockatume · · Score: 1

      Right, they're hoping to use it to perform new science missions because it can still steer, just with impaired precision.

      --
      No kidding!!! What do you say at this point?
    2. Re:2 gyroscopes left... by rubycodez · · Score: 2

      useless for finding the very slight variations in brightness on a pixel and nearest neighbors when compared to same over month or more than a year, on which kepler's detection methods depend.

    3. Re:2 gyroscopes left... by fuzzyfuzzyfungus · · Score: 2

      useless for finding the very slight variations in brightness on a pixel and nearest neighbors when compared to same over month or more than a year, on which kepler's detection methods depend.

      I imagine that that is why they are asking for proposals from scientists who have ideas for what you can do with a fairly nice telescope, already in orbit, just need to pay upkeep on the ground station, that don't require the original precision of which Kepler was formerly capable.

      As long as the optics are good, and the control is not totally shot, it's still a pretty decent telescope, and people are practically shivving each other for time on good telescopes.

    4. Re:2 gyroscopes left... by Brett+Buck · · Score: 1

      No you can't. To have 3-axis control you must have at least 3 reaction wheels with none of them colinear. With two you can only apply torque in two dimensions, specifically, the plane containing the two wheel spin axes. You cannot apply torque out of that plane.

  4. a fix by rubycodez · · Score: 4, Interesting

    deploy another gyroscope and rpg in a package that can be attached to Kepler, a practice run for comet sampling missions

    1. Re:a fix by CapeDoryBob · · Score: 0

      Either that, or return Kepler to low orbit with a single-purpose Ion Drive Space Tug, (Solar Powered?) and fix it.

      What is the required delta V? Might take a while, but the thing is expensive. Would it be worth it? Maybe not.

    2. Re:a fix by Anonymous Coward · · Score: 0

      Kepler is in a heliocentric orbit. It is cheaper to send a new probe.

    3. Re:a fix by thed8 · · Score: 1

      It's time to toss the whole mechanical gyroscope concept as long as we stay with the low bid system we doom most precision work for spacecraft. The answer, imho, is move to a laster ring or fiber ring gyroscope, then find a method of translating their output to a positioning system. Easier said than done. Or fix the procurement systems for items like this but I'm afraid a mechanical system spinning at 4 or 500 rpms is never going to last forever.

  5. Proposals due at the end of the month by Anonymous Coward · · Score: 4, Interesting

    The problem is Kepler doesn't really have the resolution for things we're interested in and may not actually be able to be pointed in certain directions due to solar panel and communications relay positioning. Best we could come up with at our brainstorming meeting this morning was parallax with our upcoming mission to Pluto and to resolve a bet on whether or not ISON will explode when it passes close to the sun later this year.

  6. What is it with momentum wheels, anyway? by Anonymous Coward · · Score: 0

    They seem to be a continuing failure point for spacecraft, despite their having been used for several decades. You'd think we would have a better understanding of how to build them with longer lifetimes by now. Any readers familiar enough with this technology to say why it's still problematic?

    1. Re:What is it with momentum wheels, anyway? by rubycodez · · Score: 1

      it's the hard drive problem, which for gyroscopes and such in space has been going on for over 40 years. we can make a batch of such systems such that some last for years, but some will fail before then. Kepler won the lottery.

    2. Re:What is it with momentum wheels, anyway? by Squidlips · · Score: 2

      Talk to Ithaco Space Systems. They built the control wheels according to this article in Nature. They supplied the failed control wheels for Kepler and Dawn and other missions....and they were not cheap. http://www.nature.com/news/the-wheels-come-off-kepler-1.13032

    3. Re:What is it with momentum wheels, anyway? by Squidlips · · Score: 1

      The Kelper crew knew that there was a problem with wheels from this company, but got assurances from them and flew with them. Oooooooppppps. We need to send the bill to Ithaco Space Systems for a new mission

    4. Re:What is it with momentum wheels, anyway? by rubycodez · · Score: 1

      contract undoubtedly says the wheels would be good for primary mission length and have probability curves for anything beyond that for which the live and dead wheels are entirely contained. space is an extremely tough environment for mechanical things.

  7. Re: Hubble gyros by Anonymous Coward · · Score: 0

    My brother is a Hubble guy.

    He says every time they've replaced gyros on the bird, they've used "improved" designs. All the replacements have been markedly inferior to the originals. At one point, there were two functioning gyros out of a set of six, and those two were the only surviving original units.

    There seems to be a problem with the engineering teams developing gyros and reaction wheels for US spacecraft. They used to get better with every iteration, back in the day...

  8. Guess Mr. Mojo Risin' was right by cellocgw · · Score: 1

    "The future's uncertain and the end is always near."

    Sorry, Kepler.

    --
    https://app.box.com/WitthoftResume Code: https://github.com/cellocgw
  9. Thanks for the journey into knowledge by james_shoemaker · · Score: 1

    This article lead me into the world of reaction wheels and their issues. Thanks /. for the education, though some data was quite hard to find out (the brand/model installed in keppler would have been useful, but I did find out it was likely an Ithaco Space Systems unit).
          From what I can find magnetic bearing reaction wheels weren't available in the torque's required by the large keppler telescope (remember it was a while ago).

  10. I wonder if Pioneers 6,7 or 8 are still working by msk · · Score: 1

    Pioneer 6 was last contacted in 2000, still operating 35 years after launch.

    I wonder if it or its companions Pioneer 7 & 8 are still functioning and if their data could still be useful.

  11. Ithaco Space Systems built the reactions wheels? by Squidlips · · Score: 2

    It seems that Ithaco Space Systems built the control wheels according to this article in Nature. They supplied the failed control wheels for Kepler and Dawn and other missions....and they were not cheap. Great job there... http://www.nature.com/news/the-wheels-come-off-kepler-1.13032

  12. Thanks, Republicans by Anonymous Coward · · Score: 0

    You with your throwing grandma (and Kepler, apparently) under the bus to give bigger bailouts to your fat cat CEO bankster buddies.

    Old people are eating canned cat food and we can't do science anymore, but at least bankers are making money!

    Thanks, GOP assholes!

    1. Re:Thanks, Republicans by Squidlips · · Score: 1

      Not true at all; it is the Obama admin that has tried to destroy planetary sci in favor of the Houston pork projects like the Rocket to Nowhere (SLS).

    2. Re:Thanks, Republicans by Sockatume · · Score: 1

      Actually, the Bush administration launched such a program (the Vision for Space Exploration, instantiated in NASA as Constellation) before Obama took office. It was nicknamed The Unfunded Mandate because it required NASA to create an Apollo-level interplanetary manned flight program with zero dollars of additional funding. The budget wasn't pretty.

      The Obama administration actually gutted that project, and replaced it with a smaller scale but not a whole lot more palatable road map.

      --
      No kidding!!! What do you say at this point?
  13. probably death of Hubble too by peter303 · · Score: 1

    The gyros have been replaced on four of the Hubble servicing missions.

  14. TESS replacement in 2017 by peter303 · · Score: 1

    TESS will study 2.5 million stars, an order magnitude more than Kepler.

  15. Drift Mode or 2-DOF? by seg9585 · · Score: 1

    Spacecraft are not designed to be 2-fault tolerant, so it's good that NASA engineers have been looking for workarounds and find other uses for this spacecraft. Having said that, what is the required pointing duration for these images? Can Kepler be put into a Drift mode (disable thrusters) for the duration of an image to ensure quiescence? I understand 2 of the momentum wheels are still functioning, which would still allow for at least 2-DOF control. Depending on the image duration and level of solar pressure/orbit perturbation forces, maybe the spacecraft could still be used for its intended duration along certain axes.

  16. Re: Hubble gyros by Yoda222 · · Score: 1

    There seems to be a problem with the engineering teams developing gyros and reaction wheels for US spacecraft. They used to get better with every iteration, back in the day...

    It's not only for US spacecraft. I was working a few years back for a French spacecraft manufacturer, and we have got 4 wheels failure in the first 6 month after launch, on 6 spacecraft (so 4 failures out of 24 wheels.) Ok you could call it US spacecraft, because it was done for an American customer, and the wheels were coming from the US(or was it the UK ? not sure, but I think US.) On the other hand, it was "low cost" satellite, and "low cost" wheels.