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International Space Station Gyroscope Fails

b00m3rang writes "Reuters reports that one of the three working gyroscopes that keep the international space station stable and in the right position stopped working, just hours after a new two-man crew moved in for a half-year stay."

68 of 302 comments (clear)

  1. Huston we have a problem! by dawg+ball · · Score: 5, Funny

    Which way is up?

  2. Sensationalism... by Inominate · · Score: 5, Informative

    The article clearly states that ONE of three failed. The story posted makes it sound like the ISS is now starting to spin out of control.

    1. Re:Sensationalism... by ottawanker · · Score: 4, Informative

      The article clearly states that ONE of three failed. The story posted makes it sound like the ISS is now starting to spin out of control.

      True, but if you'd have read any other articles, you'll have known that 2 are needed to keep the station under control, and also that another had failed previously (but now works again), so as long as any others don't fail again, they'll be fine.

    2. Re:Sensationalism... by Alter+Relationship · · Score: 5, Informative

      It's "one of the remaining three". There were 4 to begin with.
      (yes, I know, I must be new here cos' I RTFA :-)

    3. Re:Sensationalism... by chrispl · · Score: 4, Insightful

      No but it is following the media trend of making the ISS out to be a money pit that is plagued with problems. Its almost like there is a sense of schadenfreude in seeing such ambitious projects having setbacks.

      --
      What post? The one you're carrying inside your rusty innards!
    4. Re:Sensationalism... by ottawanker · · Score: 4, Informative
      Also, this story seems to make it seem as though there are now 2 gyroscopes that are broken:

      Another gyro failed two years ago, leaving only one working gyro.

      "We cannot control the vehicle without at least two gyros," NASA maintenance manager Mike Suffredini, at the Johnson Space Centre, said.


      And this story makes it seem as though 2 out of 4 gyros are broken:

      NASA announced Thursday that the second of the international space station's four stabilizing gyroscopes failed on Wednesday night, but neither the station nor the crew were in immediate danger.

      The first gyroscope broke two years ago as a result of a bearing failure. Two more are still operating -- the minimum required -- but one has exhibited power surges and vibrations over the past year. If another gyroscope breaks, thrusters on the docked Russian capsule and the station would have to assume control over the massive orbiting structure for as long as a year.
    5. Re:Sensationalism... by Morham · · Score: 5, Informative
      The article clearly states that ONE of three failed. The story posted makes it sound like the ISS is now starting to spin out of control.
      The article clearly states.
      The station originally had four gyroscopes, but one of them failed two years ago. It was to have been repaired last year, but the shuttle Columbia accident grounded the three remaining shuttles and postponed that repair.
    6. Re:Sensationalism... by hasdikarlsam · · Score: 5, Informative

      ----
      The first gyroscope broke two years ago as a result of a bearing failure. Two more are still operating -- the minimum required -- but one has exhibited power surges and vibrations over the past year. If another gyroscope breaks, thrusters on the docked Russian capsule and the station would have to assume control over the massive orbiting structure for as long as a year.
      ----

      Rather, the thrusters *could* assume control over the ISS for up to a year; the repairs are in fact likely to be made a long time before that, never mind that there is currently no need for thrusters.

    7. Re:Sensationalism... by 0123456 · · Score: 5, Insightful

      "No but it is following the media trend of making the ISS out to be a money pit that is plagued with problems"

      ISS _is_ a money pit that is plagued with problems, and serves no useful purpose that can justify its cost. It should have been scrapped years ago, before it was even launched.

    8. Re:Sensationalism... by meringuoid · · Score: 5, Insightful
      Its almost like there is a sense of schadenfreude in seeing such ambitious projects having setbacks.

      Remember how we all pointed and laughed when Mir got into trouble? Accident after accident befell the Russians and we made fun of their rickety old obsolete hardware.

      This isn't schadenfreude. It's karma.

      --
      Real Daleks don't climb stairs - they level the building.
    9. Re:Sensationalism... by JosKarith · · Score: 5, Insightful

      That kind of thinking is along the lines of the old joke about the airplane that had it's engines fail one by one, with the captain announcing that they're going to be delayed by another hour with each failure, and somebody saying when they're down to 1 engine "I hope that the last one doesn't fail or we're gonna be up here forever"
      Fail-over and redundant systems are neccessary in a situation like this where any mistake can result in impressive accident. To limp on on 3 gyros for so long is faulty thinking, and goes to show just how badly the cutbacks are affecting space exploration.
      Unfortunately it's very difficult to drum up support for what looks like a purely scientific venture when unemployment is rising and so many other projects urgently demand resources.
      What we need is a proper international effort, free of political grandstanding and nationalism.
      Like that's ever gonna happen. Maybe humanity needs to grow up a bit first before trying to climb out of it's crib.

      --
      'Don't worry' said the trees when they saw the axe coming, 'The handle is one of us.'
    10. Re:Sensationalism... by anshil · · Score: 4, Insightful

      And sometimes we ask as humanity what to do with the excess-production we are able to produce beside making food&schelter for the popolution.

      Well I think to "invest" it into Britney Spears, Nukes, Tamagochies, unnecesary Law-Suits etc. ist a far better choice than into space travel.

      "..and serves no useful purpose that can justify its cost.."

      What is _useful_ beside providing basic needs?

      --

      --
      Karma 50, and all I got was this lousy T-Shirt.
    11. Re:Sensationalism... by LordoftheLemmings · · Score: 2

      Even if one other fails they still have the thrusters to stabilize the station. Gyros are there just to save fuel, they are not critical components.

    12. Re:Sensationalism... by FireFury03 · · Score: 4, Funny

      "At this time, the box that holds that particular circuit breaker ... is outside (the station) and that implies we'll have to do an EVA,"

      So which monkey put the fuse box on the outside of a space station? :)

    13. Re:Sensationalism... by Speare · · Score: 2, Funny
      This isn't schadenfreude. It's karma.

      I'll see your schadenfreude and karma, and raise you ennui.

      --
      [ .sig file not found ]
    14. Re:Sensationalism... by Eric+Sharkey · · Score: 2

      Remember how we all pointed and laughed when Mir got into trouble? Accident after accident befell the Russians and we made fun of their rickety old obsolete hardware.

      No. No I don't. Maybe you laughed, but that's just mean. There were lives on the line, and I was genuinely concerned.

    15. Re:Sensationalism... by steve.m · · Score: 5, Informative

      No. If another one fails they switch over to thruster orientation by the Russian built modules (the FGB and SM). These consume fuel, but that's resupplied by progress flights.

    16. Re:Sensationalism... by Anonymous Coward · · Score: 2, Insightful

      "affecting space exploration."

      What, exactly, are we *exploring* in low earth orbit? It's like exploring your living room. Get rid of the ISS. It's a waste of time and money. You wanna explore? Get serious. We had space stations in the 70s. Skylab, anyone?

    17. Re:Sensationalism... by roalt · · Score: 2, Informative
      It gets even better, of the two remaining functioning gyroscopes, one had already some problems, according to this article:

      In 2002, one of the gyroscopes failed outright. Another gyroscope developed a vibration last year that perplexed mission controllers enough to rely on the Russian-built motion control system, which uses jets to change the station's position, for major orbital maneuvers. That gyroscope, however, is now in working order and one of the two still functioning aboard the ISS.

    18. Re:Sensationalism... by Viceice · · Score: 2, Insightful

      What we need is a proper international effort, free of political grandstanding and nationalism

      That is about as easy as getting the Isrealies and the Palestinians to share and live happily together on the same piece of land. Seriously.

      --
      Sometimes I wish I was a plumber, then I'd know how to deal with other people's shit.
  3. just a spacewalk by qewl · · Score: 5, Interesting

    All they need to do is a spacewalk out and restart it.

    He stressed, however, "We're not dealing with a safety issue," and added it would take several weeks to determine when to schedule the spacewalk.

    There are two gyroscopes still functioning, and that is enough to stabilize the station, Suffredini said. If one of these remaining gyroscopes fails, the station will rely on thrusters to keep it steady.


    Too bad they can't do that for Hubble too.

    --

    (\_/)
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    1. Re:just a spacewalk by Derf+the · · Score: 4, Interesting

      Can anyone tell us why it takes 2 weeks to schedule the spacewalk?

      If it was an imminent emergency, how short a time before they could get out there? Minetes, hours, days?

      --
      No. You can't look at my Sig; it's mine, and I'm not showing you.
    2. Re:just a spacewalk by angusr · · Score: 5, Interesting
      "There are two gyroscopes still functioning, and that is enough to stabilize the station, Suffredini said. If one of these remaining gyroscopes fails, the station will rely on thrusters to keep it steady."

      Too bad they can't do that for Hubble too.

      No thrusters on Hubble, of course.

      It wouldn't work for Hubble anyway - thrusters are a fairly coarse method of control, resulting it lots of banging and vibration. While on the ISS that would be fine (although some mu-g experiments would probably be upset) on Hubble it would render it unusable until the vibrations have died down after every thrust. Plus, of course, while observations take place they couldn't use the thrusters - and hence the lack of control is going to make those observations pretty hopeless anyway.

      If the robot mission to attach a gyro pack to Hubble goes ahead (which I hope it does) then it is likely to have thrusters on it - however, I would suspect that they're not for day-to-day control but to control Hubble when it's re-entered.

    3. Re:just a spacewalk by kzinti · · Score: 5, Informative

      Because you don't "just do" an EVA. Putting on a suit and going outside the station requires a lot of planning. You have to have the right time of the crew's daily cycle. You have to have the right ground personnel available to support the EVA. You have to schedule it for a time when you have sufficient TDRS (ground relay satellite) time available to cover the entire EVA. You maybe have to find a time when the station will be in the right attitude with respect to the Sun for the right amount of time, due to heating/cooling issues with the suit and perhaps (?) lighting issues with the area to be serviced. (And if the station has to be oriented a certain way, that might affect the amount of time the downlink antennas can be pointed in the general direction of the TDRS satellite.) Most importantly, the ground controllers have to draw up a complete step-by-step plan of the EVA, and the crew has to have time to study it. Take all that into account, and add the fact that the crew's every minute is planned days or
      weeks in advance, and you can see how it just takes some time to put together everything it takes to do an EVA. Going outside the vehicle is a risky activity. Extreme care is taken in its planning and execution, and rightly so.
      In a life-threatening emergency, like a sudden rapid depressurization, the plan probably calls for the crew to board the "rescue vehicle" (a Soyuz that stays docked at the station), undock, and deorbit.

      (Disclaimer: I don't work in the ISS program, but I have a general - read: vague - idea of how EVA works in the shuttle program. Consider the above to be an educated guess - but correct in spirit.)

    4. Re:just a spacewalk by kzinti · · Score: 2, Informative

      If it was an imminent emergency, how short a time before they could get out there? Minetes, hours, days?

      I asked a coworker who's a former Station flight controller and got you a better answer to this question. It would take hours at least. If the crew were to just don their suits and go outside the station, they would very quickly get extremely ill.

      The reason is that the suits they use for EVA are pressurized at only 3-4 PSI, whereas the pressure in the ISS is maintained at 14.7 PSI. With the sudden drop in pressure, the crew would get decompression sickness - "the bends". The usual EVA procedure is for the crew member who's going out to breathe pure oxygen for several hours before the EVA. This flushes the nitrogen from their bloodstream and tissues and prevents decompression sickness.

    5. Re:just a spacewalk by WormholeFiend · · Score: 3, Funny

      not to mention that the onboard computer has to agree to open the pod bay door...

  4. I shouldn't laugh... by John+Seminal · · Score: 4, Interesting
    "The gyroscope problem stemmed from an underlying failure in a circuit breaker.... At this time, the box that holds that particular circuit breaker ... is outside (the station)".

    I wonder why they would place the circuit breakers outside the space station. If those ciruit breakers are like anything in my house, they go out all the time. Or maybe it is just my power company with all the brown outs in the summer.

    I'm glad the story says this is not a critical system or a threat to the astronauts. Still, I wonder why the circuit breaker is not in a place easy to get to.

    This gives me another idea. I wonder if they have a special escape pod attached to the space station, so if some critical system goes, they can escape.

    --

    Rosco: "If brains were gunpowder, Enos couldn't blow his nose."

    1. Re:I shouldn't laugh... by Jonas+the+Bold · · Score: 5, Funny
      I wonder why they would place the circuit breakers outside the space station. If those ciruit breakers are like anything in my house, they go out all the time.

      I think it's a pretty good bet the circuit breakers on the International Space Station are absolutely nothing like the ones in your house.

      --
      Everything seemed to be going so nice
      'till the end of all beings punched right through the ice
    2. Re:I shouldn't laugh... by DrMrLordX · · Score: 2, Interesting

      Well, the ISS is modular, isn't it? Something that is currently on the outside of the ISS might be inside later. They seem to imply that the position of that particular breaker is temporary(either that, or its status as being "outside" is temporary).

    3. Re:I shouldn't laugh... by meringuoid · · Score: 4, Funny
      I wonder why they would place the circuit breakers outside the space station.

      Why, for dramatic tension when somebody has to go EVA to replace the AE-35 unit, of course.

      --
      Real Daleks don't climb stairs - they level the building.
    4. Re:I shouldn't laugh... by eclectro · · Score: 4, Informative

      I wonder why they would place the circuit breakers outside the space station

      I think the larger question is why they didn't engineer the breakers so they could be reset with servos or other electromechanical means.

      Still, I wonder why the circuit breaker is not in a place easy to get to

      Space is a difficult enviroment to engineer for. They probably put the circuit breakers outside thinking that they would rarely need to be used, if at all. By placing them outside they made more space inside the station.

      I wonder if they have a special escape pod attached to the space station

      There is actually a Soyuz spacecraft attached to the station to act as a kind of lifeboat if need be.

      Remember in the original Star Trek on how Scotty never had enough dilithium crystals? I always thought that was kind of funny that they couldn't find a way to stash a couple of extra boxes of crystals somewhere.

      It seems to be that way with NASA and gyros.

      --
      Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
    5. Re:I shouldn't laugh... by torpor · · Score: 2, Informative

      The pods have a shelf-life. The one thats been there already is going back down with the old crew - the reason they can't have more than two is that they have to stagger the operational lifetime of the pods, since after 6 months in space (or some such thing) its no longer 'safe' ...

      --
      ; -- the corruption of government starts with its secrets. a truly free people keep no secrets. --
    6. Re:I shouldn't laugh... by arikol · · Score: 2, Interesting

      To answer the comment about the servos, complexity is avoided as possible, you would need wiring for each servo, a power source for the servos and probably a few other (probably needing more power conduits etc.) Another thing, Weight! The cost of sending 1 kg of payload into space is around u$5000 on the Soyuz system and around u$10.000 on the shuttle. I think that might also be the reason for not having a well stocked maintenance facility onboard.

    7. Re:I shouldn't laugh... by tiger99 · · Score: 4, Interesting
      And weight (of wiring etc) is probably one of the main reasons why the breakers are outside (might be to minimise the length between source and load), the other probably being that you would not want the wiring on the unprotected side of the breaker inside, because of what would happen if it shorted. At the very least, unpleasant smoke and fumes, possibly fire. Virtually every cable insulation will, given sufficient energy, burn or emit toxic fumes. The exceptions may be glass and ceramic, not really practicable.

      And before anyone mentions PTFE (Teflon), well it may be OK in a frying pan, but a wiring fault would result in the release of fluorine gas, which would resct with moisture in the air to give hydrofluoric acid. Not good. A frying pan fire could presumably be very serious if the temperature got too high, IIRC about 400 deg C. If you inhale hydrofluoric acid, or get a small amount on the skin, you usually die, fairly unpleasantly. Someone who went to school with me died that way, many years ago, age about 22, from a small skin splash of HF even though it was quickly washed off.

      Teflon has been, and probably still is, used in unmanned satellites, OK in the smaller ones where a total loss is not an absolute disaster, but I think it would be frowned upon in things which earn serious money and have to keep working, such as comms sattelites. There will be Teflon bits in the microwave equipment, and in some mechanisms, which can't otherwise be lubricated, but not necessarily on normal wiring.

      I don't know what kind of wire NASA currently use, the aerospace industry has been through a variety. At one time, Kapton seemed good, we now know that it is lethal in circuits which have sufficient energy to initiate arcing.

      BTW, Kapton and Teflon are OK where there is always insufficient energy available to seriously raise the temperature, in fact I like working with Teflon in particular, but only in the right place.

    8. Re:I shouldn't laugh... by kzinti · · Score: 4, Informative

      I wonder why they would place the circuit breakers outside the space
      station.


      Well, there are only so many places inside where you can put stuff. Something has to go outside, so you put the stuff out there that should rarely, if ever, need servicing. The stuff that needs more frequent access goes inside. Circuit breakers are (speculating here) relatively simple, well-understood technology that you don't expect to have to replace. They should "just work".

      If those ciruit breakers are like anything in my house, they
      go out all the time.


      Note that they're not going out to reset the breaker, but to replace it. The breaker can be monitored and reset remotely. In fact, the breaker was reset yesterday - probably from the ground - but it tripped open again. I believe the working theory is that the gyro's OK, but that the breaker is bad - tripping when it shouldn't. If this is true, then replacing the breaker will recover the gyro without having to replace it (a much more difficult affair).

  5. Is it just me? by Zakabog · · Score: 5, Funny

    Or is this picture a little creepy? The american astronaut looks like a serial killer or something and the russian looks like he's afraid because the american looks like a killer...

    1. Re:Is it just me? by TwistedSpring · · Score: 2, Informative

      That would be Hi-La-Ri-Ous if they had actually gone up in the Shuttle. They actually went up in a Soyuz capsule.

    2. Re:Is it just me? by Anonymous Coward · · Score: 5, Funny

      That photo is faked. The astronauts are most certainly not floating in space with the ISS behind them. I expect better from NASA.

    3. Re:Is it just me? by OwlWhacker · · Score: 2, Funny

      It seemed to me that they were probably both thinking "Man, I bet I look really dumb wearing this."

    4. Re:Is it just me? by Anonymous+Custard · · Score: 2, Funny

      It seemed to me that they were probably both thinking "Man, I bet I look really dumb wearing this."

      They're not actually wearing those spacesuits, they've just got their heads through holes in a wall that's painted to look like two guys in spacesuits.

  6. FUD! by Docrates · · Score: 5, Insightful

    Reuters reports that the gyroscope that keeps the international space station stable and in the right position stopped working, just hours after a new two-man crew moved in for a half-year stay."

    Did you phrase it that way because you're a professional reporter and are used to getting paid to scare people into buying the crap you write, or are you just being a troll?

    The article (and common sense) state that there's redundant functionalirty involved, i.e., there are two gyroscopes left that can handle the load and if that fails they can still keep it going with thrusters for over 6 months.

    --

    There are two kinds of people in the world: Those with good memory.
  7. Don't get locked out by jginspace · · Score: 3, Funny

    Any spacewalk to fix the gyroscope circuit breaker would be only the second time both station crew members would be outside the space station, leaving no one inside. I hope they remember the key.

  8. That's not a bug, that's a feature! by weiyuent · · Score: 4, Funny

    NASA has finally decided it's time the ISS had centrifugal artificial gravity.

  9. 50% stop working?? by fldvm · · Score: 2, Informative

    Now it is up to 2 of 4... http://www.sltrib.com/2004/Apr/04232004/nation_w/1 59922.asp

  10. I just have to do it.... by arduous · · Score: 5, Funny

    In Soviet Russia, spacestation rotates you!!

    --
    "It's the smell! If there is such a thing." Agent Smith - The Matrix
  11. Makes you wonder... by NivenMK1 · · Score: 2, Interesting

    This makes you wonder what specification of hardware gets used in spacefaring vehicles/structures.

    It seems that over history, the spacefaring versions of our technology are quite inferior to what we have planet-side. On typical space vehicles, this is because the vehicles were built so long ago. The ISS is a relatively new invention, and the number of bangs, bumps and hiccups seems to be more or less consistant with it's much older counterparts.

    On a sidenote, anyone know if it has enough mass to impact earth's surface if it should come down?

    1. Re:Makes you wonder... by fucksl4shd0t · · Score: 4, Informative

      It seems that over history, the spacefaring versions of our technology are quite inferior to what we have planet-side. On typical space vehicles, this is because the vehicles were built so long ago. The ISS is a relatively new invention, and the number of bangs, bumps and hiccups seems to be more or less consistant with it's much older counterparts.

      I think you misunderstand the problem. Engineering gadgets here on earth is simple compared to engineering gadgets to be deployed in space. We've lived in the relatively friendly environment of the earth for our entire racial life. Space is a hostile environment which we have only been exploring in a limited fashion in the last fifty years or so.

      Compare the space shuttles to your car. Sure, they probably cost more in maintenance than your car, but they were engineered in the 70s, and with a couple of exceptions, they're still operational. I'll be the ISS has been in continuous operation for longer than any gadget in your house.

      Anyway, the first problem is that they have to engineer devices that are capable of withstanding the amount of thrust they'll be under just to be launched out of the atmosphere. Second problem is that these same devices have to survive in vacuum, and in atmosphere (they're built down here). Third problem is they have to last for a long time, because solving the first two problems is so expensive that building replacements is very cost prohibitive. Fourth problem is that they're built by the lowest bidder, and frequently also engineered by the lowest bidder. :)

      It's too easy to point at something in space and compare it's performance to any given gadget you own. Now try strapping that gadget to a rocket and launching it into orbit, and if it survives, then you can make your comparison.

      --
      Like what I said? You might like my music
    2. Re:Makes you wonder... by HeghmoH · · Score: 4, Informative

      Compare the space shuttles to your car. Sure, they probably cost more in maintenance than your car, but they were engineered in the 70s, and with a couple of exceptions, they're still operational.

      I'd just like to point out that those "couple of exceptions" are actually 40% of the fleet, and that their removal from service resulted in the sudden and violent death of everybody inside.

      --
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  12. How do these things work? by The+Fanta+Menace · · Score: 3, Interesting

    The article says that if another fails, they will have to use thrusters to keep the thing stable. So can someone perhaps explain to me what the gyroscopes physically do to keep it stable?

    --
    -- Even if a god did exist, why the fsck should I worship it?
    1. Re:How do these things work? by meringuoid · · Score: 4, Informative
      It's an angular momentum thing; properly describing it needs a fair amount of moderately heavy Newtonian mechanics. How's your calculus?

      Simple intro

      --
      Real Daleks don't climb stairs - they level the building.
    2. Re:How do these things work? by AlecC · · Score: 5, Informative

      Ever tried to twist a gyroscope? You can use them in two ways: if you don't try to push them, they stay oriented the same way so yo have a directional reference. But if you ty to move, they "push" back. This gives you something to "push against" in order to twist yourself in space. You don't need to spend expensive reaction mass hauled up from earth, you just use electricity from your solar cells, and you get a much smoother and more accurate control than thrusters.

      However, a single gyro can only handle positioning about two axes - you can rotate it about its spin axus as much as you like. So for three axis rotational stabilisation you need at least two gyros at 90 degrees to each other.

      --
      Consciousness is an illusion caused by an excess of self consciousness.
    3. Re:How do these things work? by FireFury03 · · Score: 3, Informative

      Remember theres (practically) no friction in space - a small amount of energy can accellerate a massive object (very slowly). I'd guess that the amount of accelleration needed to keep an orbiting body stable is pretty low. Of course if there was a metior strike, etc then it would probably send the station into a spin, but in that case (if there's enough of the station left) you would fire up the thrusters to provide a much bigger accelleration.

      Although I'd be quite interested to know how massive the gyros are and how fast they spin. Also, how quickly can they spin up a gyro from stationary - I'd expect they have to do this quite slowly since the torque of spinning up a reasonably massive gyro would have some effect on the spin of the station.

    4. Re:How do these things work? by Keebler71 · · Score: 4, Informative
      Actually, most of the other post are defining the wrong type of gyroscope. Gyroscopes have been used for decades for the purpose of navigation. Much like a top encased inside two gimbals, the gyro maintains its orientation despite any motion of the platform to which it is attached. Thus it is used in aircraft, ships, submarines and spacecraft to determine the vehicles' orientation.

      However, that is not the type of gyroscope that has failed here! In the last couple decades, gyroscopes have been used as actuators to actually provide the TORQUES necessary to MANEUVER space vehicles. This is very different from the much more common use of gyros simply to determine attitude. In fact, these gyroscopes are more correctly referred to as Control Moment Gyrospcopes or CMGs. (Incidently, they come in two flavors, single and dual gimbaled - with the ISS using the much less common and more complex [read prone to failure] dual gimbaled CMGs (DGCMG)).

      A CMG works as a torque amplifier. You essentially spin up the inner element to a high rpm (usually 3000-5000 rpm) and then apply a small torque to the outer gimbal. The the gyroscopic rigidity of the inner rotating element resists this torque and the result is a much-amplified reaction torque imparted on the vehicle.

      Traditionally, three-axis stabilized spacecraft that require fine pointing control have used reaction wheels or momentum wheels for control. CMGs allow for orders of more magnitude of more torque (for an equivalent mass alternative) and more momentum storage (unfortunately, momentum is conserved even in space, so if you impart an angular rate to a spacecraft, you must have some element inside the spacecraft to 'store' an equal an opposite momentum - this is what actually limits a spacecraft's slew rate). The downside of CMGs is that they are mechanically complex (don't even get me talking about null-spaces) and that high rpm inner element must be lubricated extremely well if you want the vehicle to perform for years without an oil change (as those are hard to come by in LEO); thus they tend to higher failure rates. The solution to this has tended to be to add redundant CMGs (which is probably still a better option than using less capable alternatives.)

      --
      "It takes considerable knowledge just to realize the extent of your own ignorance." - Thomas Sowell
  13. Aww sorry people. by Retep+Vosnul · · Score: 2, Funny

    Mmpff, So for the second time in history a dutch man goes into space.
    And first thing he does is break the bludy spacestation !.
    So typical.

    On behalf of all dutch , sorry people, we can't help it, we like to break things.

    --
    -- forget /. It's gone.
    1. Re:Aww sorry people. by Anonymous Coward · · Score: 3, Funny

      Google reported it like "An american, a dutchman and a russian have gone into space". I thought it was the beginning of a joke for a second there.

  14. If you're wondering how a gyroscope works by trystanu · · Score: 5, Informative

    If you're wondering how a gyroscope works and what it does:

    How stuff works has a nice article.

    Nasa's also got a page about how they're used in space shuttles

  15. Cheesy plot device? by Anonymous Coward · · Score: 4, Funny

    From the article:

    "At this time, the box that holds that particular circuit breaker ... is outside (the station) and that implies we'll have to do an EVA," Suffredini said in a telephone news conference, using the acronym for extra-vehicular activity, or spacewalk."

    Right...The controls for the fence are in the shack across the lot, past all the dinosaurs; the satellite uplink is in the shack across the lot, past all the marauding aliens; the circuit breaker is in the box, outside the space station. Go fix it Dave.

    Any of the astronauts wearing a red shirt by the way?

  16. Bureaucracy by Anonymous Coward · · Score: 2, Insightful

    and added it would take several weeks to determine when to schedule the spacewalk.

    Eh? Damn bureaucracy. When it takes weeks to SCHEDULE something you know that something is wrong. What happened to good old flexibility?

  17. And Illiad knows the reason... by schabi · · Score: 2
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    plim-plam-plompudding
  18. Moving is dangerous by BanSiesta · · Score: 2, Funny

    Figures. Stuff always breaks when you move. They should be glad the moving guys avoided dropping the piano down the stairs or putting a hole in the wall.

  19. Place your bets! by dj245 · · Score: 2, Funny
    Who will lose their last gyroscope first? Hubble or ISS?

    Hubble has lost 3 of 6 gyros. It needs 3 to stay pointed in one direction and not spin out of control.
    ISS has lost 1 of 3 gyros. It needs 2 to stay locked in 2 axis (I would imagine) which is crucial to keep one side pointed at "space" and one at earth.

    Who will fail first? The beloved Hubble or the much-berated ISS? Only time, or perhaps a Foresight Exchange claim can tell.

    --
    Even those who arrange and design shrubberies are under considerable economic stress at this period in history.
    1. Re:Place your bets! by FireFury03 · · Score: 3, Interesting

      AFAIK, the only axis a gyro can't be used to control is it's spin axis, so you should only need 2 gyros to control all 3 axis - anyone know why hubble needs 3 to keep it stable?

  20. Hi guys by mcraig · · Score: 2, Funny

    Hi guys welcome aboard the ISS, um just asking but did you happen to bring a gyroscope.. nope oh well never mind we should be ok unless another one.. *breaking sound*.. ahh crap

  21. Gyroscope is not completely faulty, ... by thrill12 · · Score: 2, Informative

    but needs to be recalibrated, as Andre Kuipers (ESA) stated on an interview this morning with Dutch television (Dutch language).

    --
    Slashdot: stuff for news, nerds that matter, matter for news, stuff that nerd
  22. In Other News by psiphre · · Score: 2, Funny

    In other news, america's sensationalization and hype step up to new levels to combat the desensitization to hype brought on by Fox News' continuous looping of the same six stories four times per day.

    top headline right now: nobody cares! an eyewitness at the NASA command center shrugged and commented "It really doesn't matter, they still have two gyros left. Ooh! Gyros. I think I'll have greek food for lunch." the pudgy scientist then led twelve of his friends to Olive Garden.

  23. I'm sorry, but that's wrong. by AzrealAO · · Score: 4, Informative

    They will resume thruster orientation maintained by the Russian modules. the Zarya Control module (Formerly the FGB Tug), and the Zvezda Service Module which is how the altitude and orientation were maintained until the Gyroscopes were installed as a part of the Z1 Truss.

    Zarya was launched in November 1998.
    Unity was attached by Shuttle Endeavour in December 1998.
    Zvedza docked to the fledgling station on July 25th, 2000.
    The Z1 Truss was installed by Shuttle Discovery in October, 2000.
    The Control Moment Gyroscopes which are an integral part of the Z1 Truss, weren't activated until Assembly Mission 5A in February 2001.

    Yes, this is a big deal, it will not however, result in the station tumbling out of control and dooming it forever.

  24. gyroscope with no moving parts by peter303 · · Score: 3, Interesting

    JPL has been marketing a fiber optic "gyroscope". It using inferometry in long fiber loop. Motion will cause a loop of light to doppler shift out of phase. Four of these coils, each on the face of a tetrahedron, will measure any rotational motion. No parts to break or wear out.

    I presume NASA spacecraft are using mechanical gyros?

    1. Re:gyroscope with no moving parts by Ignorant+Aardvark · · Score: 2, Informative

      The gyroscope that failed isn't used to measure orientation in space, but rather, to CONTROL orientation in space. You ever played around with a gyroscope, or a bicycle wheel on an axis, or anything? When you spin it up it resists movement along certain axes in relation to its own axis of rotation. It "pushes back". The gyros being used on the ISS are big massive suckers that are used to control the ISS's position in space, not to simply measure it. Fiber optic gyros would thus not suffice for this purpose.