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NASA Space

Space Station Solar Equipment Showing Damage 113

Posted by CmdrTaco from the don't-touch-me-there dept.
bhmit1 writes "The latest space walk has turned up some bad news for the problematic solar panels: metal shavings. From the article: "The rotary joint, 10 feet in diameter, has experienced intermittent vibrations and power spikes for nearly two months. Space station managers were hoping a thermal cover or bolt might be hanging up the mechanism. That would have been relatively easy to fix, so they were disheartened when Daniel Tani radioed down that metal shavings were everywhere. 'It's quite clear that it's metal-to-metal grating or something, and it's widespread,' Tani said.""
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Space Station Solar Equipment Showing Damage More

Space Station Solar Equipment Showing Damage

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  • that's not metal-on-metal grating (Score:5, Funny)

    by jollyreaper ( 513215 ) on Monday October 29, 2007 @08:02AM (#21155965)
    That's not metal-on-metal grating in the bearings, that's just some sick bastard playing Yoko Ono.
  • It's one thing to get the metal on metal thing going in your car and then be stranded alongside the road. But at least your life would be in no danger. It's quite another to get the metal on metal thing going and getting stranded in space. Tow trucks for space stations cost a considerable amount more. And the mechanics... don't get me started on the mechanic's wages.

    • Re:Towing in space (Score:5, Interesting)

      by Migraineman ( 632203 ) on Monday October 29, 2007 @08:23AM (#21156107)
      Towing in space has been done before. Grumman sent North American Rockwell an invoice for towing [geocities.com] their crippled spacecraft home. The rate per mile seems pretty reasonable too.

      All joking aside, this is going to be a bear to fix. The best scenario would be that the drive gear was munching an insulation blanket. The debris would be friendly to space suits, and should only be labor intensive to clean out. If the gears are grinding on each other, the debris will be sharp and hard. That would be "bad" and I'd expect NASA to seriously consider returning the entire assembly to earth for repair. Expensive, but much less likely to kill someone.

      I'm of the opinion that the drive system on this beast is probably over-engineered. It should resemble a Ford F-150 differential - loose tolerances, and designed to run for many millions of rotations without much maintenance. There's absolutely no need for the solar array to have precision pointing capability. I really do hope that the problem isn't due to over-engineering, but I wouldn't place a bet.

      • I'm of the opinion that the drive system on this beast is probably over-engineered. It should resemble a Ford F-150 differential - loose tolerances, and designed to run for many millions of rotations without much maintenance. There's absolutely no need for the solar array to have precision pointing capability. I really do hope that the problem isn't due to over-engineering, but I wouldn't place a bet.

        Over engineering? Then we wouldn't be talking about an F-150. We would be talking about a Chevy Silverado or any other GM POS.

      • Re: (Score:1)

        by sdaemon ( 25357 )
        Shoot, I even have a spare Ford 3.08 ratio differential. NASA can get it off me for what I paid for it, or I'll even give it to them if they let me do the installation ;)

      • Re:Towing in space (Score:5, Informative)

        by Rei ( 128717 ) on Monday October 29, 2007 @10:55AM (#21157705) Homepage
        These *were* designed to run for many rotations. The design specs for the SARJ (Solar Alpha Rotary Joint) were that the 10.5'x2.5', 2,500lb structure would rotate at 4 degrees per minute without imparting vibration to the laboratories that would mess up the microgravity experiments, for a minimum of 15 years. They also have to transfer 60kW of power at 160V while rotating through a "roll ring". These were the design specs, and they were engineered around that; this break was not supposed to happen. That's why this is considered an anomalous event. It's not a case of an insufficient design goal.

        One thing that a lot of people don't realize is that there's still a tremendous amount of stuff that we don't know about living and operating things in space. It's deceptively similar to our world; just picturing it being like an Earth where you can't breathe and you can have enough velocity to fall in a circle simply doesn't cut it.

        Example: TSS-1R. Space Shuttle Columbia deployed this as part of NASA's series of experiments with orbital tethers (for "hanging" craft from other craft and for raising and lowering orbits). When the tether was 19.7km out of the desired 20.7km deployed, it snapped. Evidence suggested arcing and burning in the tether. Why? The tether was at -3500VDC compared to the orbiter, with no current flowing through it. A minor defect in the tether's insulation left the conductive core exposed to space. Unexpected trapped gas in the insulation bubbled out in the vaccuum of space. This gas created a path for conduction to the orbiter, creating a plasma arc that burned away at the tether until the remaining strands failed under the strain.

        In hindsight, it's easy to look at this and say, "Oh, we should have had a short-detection system." However, hindsight is 20-20. We've learned a great deal from past experiences, which unfortunately means that systems have to get more complicated. For example: where does the heat from running the drive motor for the arrays go? Why, it goes all over the place! It took an entire design study [harvard.edu] just to figure out where it would be going and what to do with it. Now picture unexpected current draws (creating more heat) from the metal shavings thrown into the mix, and what that will do for heat load, or what the metal shavings themselves could get into or allow to conduct unexpectedly. Things get tricky fast.

        Too many people seem too eager to see a "finished product" in space. It's important that things like the ISS be seen foremost as learning experiences. In this case, I'm sure we'll see the same thing.

        • Re: (Score:2)

          by MikeyVB ( 787338 )

          Example: TSS-1R. Space Shuttle Columbia deployed this as part of NASA's series of experiments with orbital tethers (for "hanging" craft from other craft and for raising and lowering orbits).

          That was a nice tid bit of information, thank-you. Looking it up out of curiosity, it also appears that the TSS-1R experiment on STS-75 was the first time Linux was used in orbit! (http://en.wikipedia.org/wiki/STS-75#Trivia [wikipedia.org])

    • Re: (Score:3, Funny)

      by FudRucker ( 866063 )
      seen on a sign in a mechanic's garage:

      Labor $10.00 Hr.
      If you watch $15.00 Hr.
      If you help $25.00 Hr

    • Re: (Score:2)

      by mpe ( 36238 )
      It's one thing to get the metal on metal thing going in your car and then be stranded alongside the road. But at least your life would be in no danger.

      Actually your life could well be in danger, from idiots crashing into your broken down car...

      It's quite another to get the metal on metal thing going and getting stranded in space. Tow trucks for space stations cost a considerable amount more.

      Together with having a long callout time...
      • I would think my life would be in considerably more paral if I was streaking across the sky in a ball of plasma. While survivable, car hitting my car might be dangerous too.

    • pfft. (Score:3, Informative)

      by djupedal ( 584558 )
      "It's quite another to get the metal on metal thing going and getting stranded in space"

      They have spares on board. Excepting the fact that it came as a surprise (a similar setup is ok), this is a non-issue.

  • Metal to metal grating... (Score:3, Funny)

    by RandoX ( 828285 ) on Monday October 29, 2007 @08:10AM (#21156013)
    ...or something.

    Thanks for the technical breakdown. Sounds like the way Beavis would describe it. That's comforting. Or something...
    • Hey dumb ass you are in a space suite in probably the second most unforgiving environment (under the ocean is the first most unforgiving). He probably gave his best educated guess to express to NASA on the ground that they have a problem. Then NASA will figure out a plan of action to figure out in more detail what the problem exactly is. So yeah I guess you are always sure what the problem is 100% of the time? Maybe you should go into space it sounds like your arrogant ass could save the day.

    • No, man (Score:1, Offtopic)

      by tietokone-olmi ( 26595 )
      The Beavis version would be more along the lines of... "Uh huh, huh huh huh, uh huh, or something... I am CORNHOLIO! I need metal shavings for my bunghole! Bungggghoooole! Gagagagagaga. I have no bunghole! Or something."

  • Will a replacement fix it? (Score:5, Insightful)

    by _merlin ( 160982 ) on Monday October 29, 2007 @08:13AM (#21156041) Homepage Journal
    I noted that they intend to fit a replacement joint, and are limiting the travel of the solar panel(s) in the mean time. My question is, do they know what the source of the problem actually is? Is it a manufacturing defect, damage or wear and tear in the currently fitted joint? If it is, replacing it is a reasonable solution. But if it isn't - i.e. if there's a design or operational problem - replacing it will just be a temporary band-aid, and the same thing will happen again sooner or later.
    • Replacing things that are known to have problems and hoping it doesn't happen again is hardly unheard of with NASA though. Prior to the Columbia accident they slowly reduced the severity that they assigned to foam strikes - replacing the affected RCC panels and shrugging it off.

      There's such a push to get the ISS finished before the Shuttle finally hits EOL, and as a result corners seem to be being cut far too often.

      • Re:Will a replacement fix it? (Score:5, Interesting)

        by mha ( 1305 ) on Monday October 29, 2007 @08:34AM (#21156207) Homepage
        So how would you propose these things are done? I mean, things that no one's ever done before, and which you can't really simulate?

        An anecdote from my days of working for a huge German company (240000 employees) at Oracle (first job after university): I was part of the 32-64bit porting team. The question came up, are customers going to need additional or larger hard drives for the 64bit version of Oracle?

        The answer from the Germans: Well, you've got the source code. Examine all structures in the code that end up on disk and count the bytes. (we know how many Bytes an "int" takes up on 32 vs. 64bit, etc.)

        The answer from the Americans: Well, you've got the source code there. Just compile it and see what happens!

        You know, while the German approach (I *am* German) sounds a lot more "scientific" and exact I would say the American way was not just better, but the only one that actually WORKS outside a simulated computer environment with a limited number of known-in-advance factors.

        So again, how would YOU go about discovering the unknown? *I* would do just what NASA does, and what humans have done for millenia: Try, fail and try again, never approaching any ideal solution but something that works for now, until the next unforeseen thing happens.

        Of course, in the western world everything that even LOOKS like risk has to be eliminated: from hot coffee to horses with tourists on them going any faster than a slow walk (I'll NEVER go on any tourist expedition on a horse in the US again, in Germany my friends who've never been on a horse before were forced to "survive" gallop several times in a 2 hour tour - and did so with relative ease).
        • (I welcome the language patrol but this time I'm ahead of you ;-) )

          I should have said "had been on a horse before", not "have been". I wouldn't add yet another post if I hadn't had relevant experience (with getting corrected) before at ./ (but as I said, I don't complain or mind, but maybe some moderators do who - rightly - mod this "offtopic")
        • "Try and fail" can be a bad approach when you're dealing with the space shuttle, which is simultaneously the least reliable and most expensive option.

          Another option would have been to bring back the Saturn V, which despite having 10 times the payload capacity of the shuttle, costs less for a single launch. We could have had the space station built long ago for much less cost if we weren't so hell bent on using our space shuttles for everything.

          • Re: (Score:3, Informative)

            by AJWM ( 19027 )
            In the original scheme of things -- i.e. back in the late 1970s when the Shuttle was being built -- the plan was that while the Shuttle would carry the vast majority of "medium size" payloads, they'd keep Delta around for small payloads (Delta has been upgraded quite a bit since then) and Saturn V around for the large payloads.

            Needless to say, that plan was scrapped early on. Probably just before they overhauled the VAB and Pad 39 to make them Shuttle-compatible but Saturn V-incompatible.

        • Re: (Score:2)

          by p0tat03 ( 985078 )

          Hardware (especially aerospace hardware) tends to be a bit different than software. Like you said, with a software package I can discover an unknown just by trying. What's the worst I can do? Crash? Blue screen? Oooh, maybe if I was *really* bad I could fry the motherboard. Big deal.

          Imagine if we tried that mentality on the shuttle. Er, we don't know what this thing will do in space, well, let's launch it and hope we don't just send 9 astronauts to their doom!

          Different tools for different jobs eh? Space

          • Imagine if we tried that mentality on the shuttle. Er, we don't know what this thing will do in space, well, let's launch it and hope we don't just send 9 astronauts to their doom!

            First try: It's seven astronauts. Need Another Seven Astronauts.

            Too old-school?

            Okay, second try: Imagine if we did. Why, we'd be zipping those babies up there with big ol' blocks of ice banging into it willy-nilly, and never fear the damage it may cause!

            Yeah, that's more like it.

          • Re: (Score:3, Insightful)

            by mha ( 1305 )
            It *is* the same, however you twist it. Of course you try a little harder when lifes are at stake. You also drive more carefully when the road seems dangerous or you are not wearing a seatbelt (on the average). Not sure what you're trying to say. When flying was discovered and aircrafts developed many died. When we went into space the human cost was low ONLY because of the enormous effort - very few people have been up there at all, and many, including those who went to the moon, were just lucky - there was

            • Re: (Score:2)

              by p0tat03 ( 985078 )

              That's my point though, with a computer system it is often possible to run a "full on" test that very, very closely approximates the real thing. Grab a few boxes, set up your software, and crunch it through a gauntlet of tests, and see where it fails. The same approach exists in hardware engineering, but with more limitations. You can test an engine by itself, since destroying a single prototype sucks, but is practical for most intents and purposes. What you can't do is integrate all those systems into the

        • So again, how would YOU go about discovering the unknown?

          Flight Simulator. It's warmer in the basement. And there are snacks.

        • Space travel, the trial-and-error way, eh? You mean, Wan Hu [wikipedia.org] style? ;)

          "Early in the sixteenth century, Wan decided to take advantage of China's advanced rocket and fireworks technology to launch himself into outer space. He supposedly had a chair built with forty-seven rockets attached. On the day of lift-off, Wan, splendidly attired, climbed into his rocket chair and forty seven servants lit the fuses and then hastily ran for cover. There was a huge explosion. When the smoke cleared, Wan and the chair were
      • Cutting corners in what way? As far as the design of ISS goes, most of these designs are old news at this point. Most of the hardware for the ISS is currently just sitting in storage waiting to be loaded and lifted into space. Considering that they've got an identical joint on another set of panels that's showing no damage, it's probably not the case of it being a mechanical design defect. I think it's more likely that the joint got contaminated either while being installed or while it was being loaded.

    • Re: (Score:3, Insightful)

      by Guysmiley777 ( 880063 )
      The problem is with the right side solar alpha rotary joint, what I infer from that is the joint on the left side panel joint is working fine. Which would seem to indicate a part failure rather than an engineering problem. But I'm sure nobody can say for sure until they get a look at the failed joint.
      • Well even a part failure is an engineering failure in a space environment - i.e. if the part failed because it wasn't manufactured to tolerance, then why was this missed; If it was manufactured as designed, why was the design wrong? The fact it is a different side to me
        Either way they need to understand why this failed, how to fix it, and how to make sure this doesn't happen again.

        i.e. by definition, someone somewhere screwed up - what the concern needs to be is why this screwup was missed and how to make s

  • Dust buster? (Score:3, Funny)

    by advocate_one ( 662832 ) on Monday October 29, 2007 @08:23AM (#21156109)
    I was gonna suggest using a dustbuster to sweep up the shavings... but there's nothing to suck...
    • If the shavings are of a ferrus material a magnet might be a good idea. Otherwise I might suggest canned air. Though once I think about it you'd still have the problems of the shavings coming back due to the microgravity of the station.

      A high tech version of the push sweeper might be a better idea - rotating brushes pick up debris and pull it into a storage chamber.
      • I can't imagine the shavings coming back being a problem; the atmospheric friction already decelerates the space station so this should have a much larger effect on any shavings.
        • In the long term, yes. Especially if you concentrated on reducing the orbital velocity of the shavings when you removed them. However, the microgravitational effects of the ISS would be quite substantial in the medium term. So they might come back. It already appears to be enough to hold the shavings despite any friction.

    • Re: (Score:2)

      by Ced_Ex ( 789138 )
      They could use a swiffer dust mop.

  • From the TFA (Score:4, Funny)

    by denzacar ( 181829 ) on Monday October 29, 2007 @08:30AM (#21156159) Journal

    "It's quite clear that it's metal-to-metal grating or something, and it's widespread," Tani said.

    "Wow," said his spacewalking partner, Scott Parazynski.
    Its nice to see those "Keanu Reeves Linguistic School" classes paying off for astronauts.

  • One hell of a gear box (Score:5, Insightful)

    by BadHaggis ( 1179673 ) on Monday October 29, 2007 @08:58AM (#21156469)

    The SARJ, 10.5 ft in diameter and 40 inches long, will maintain the solar arrays in an optimal orientation to the sun while the entire space station orbits the Earth once every 90 minutes. Drive motors in the SARJ will move the arrays through 360 degrees of motion at four degrees per minute. The joints must rotate the arrays smoothly without imparting vibrations to the laboratories and habitation modules on the station that would impact microgravity-processing activities. At the same time, 60 kW of power at 160 volts and multiple data channels are carried across each joint by copper "roll rings" contained within. From: Google Cached Lockeed Martin Article on the Panels. [64.233.167.104]
    The joints in question are huge and as this article points out any vibrations back into the ISS could cause problems with other equipment or experiments. Additionally power is transferred back to the ISS through copper rings in the unit itself. Any metal which provides a better circuit path than the copper would cause the power spikes.

    Opening this thing up would be something like trying to rebuild an Automatic Transmission, then add the complexity of doing this in micro-gravity. It would probably be easier for NASA to send up a complete replacement instead of trying clean out all of the metal shavings and replace the parts that are damaged.
    • This might be a good time to try a small robot. I am guessing that a bolt came lose and is getting ground up. It may be possible to send a small robot up there, inspect it, and clean it up. I just wonder how far along the robotic tech has moved

    • Re: (Score:3, Insightful)

      by mikelieman ( 35628 )
      Isn't this, then, *exactly* the time to learn how to do this stuff on-site? No-one said that learning was ever "easy".

    • And, if possible, NASA will be able to take broken joint after it is replaced and bring it down with the Shuttle for examination. A full deconstruction of the broken piece would allow them to figure out what's going on, determine whether it's a manufacturing or engineering problem, and devise a fix.
  • Someone must remember the Asimov story about the space mechanics sent to check out some satellite and inside they find some kind of metal worm burrowed into the thing.

    Metal on Metal grinding? Or have we been found?
  • "...twenty year old piece of machinery needs upkeep."

    In other "news", What is now a supercompuer will fit in your hand in a few years. Researchers achieve amazing memory density. And so on.

    What would be news (for nerds, stuff that matters) would be "aging solar panels repaired, here's how they did it", "Researchers build supercomputer out of 1,000 networked cell phones", or "new memory device with no moving parts has greater capacity than the largest hard drives and can be manufactured for twenty dollars pe
  • Ya know, a metal shaving, released from a Chinese satellite (with a Clinton-Gore'94 bumper sticker) moving at 17,000mph or more is a cheap way to supress satelittes, and, it's been done before. I hope it's just the wearing of a part, and not the start of an orbit-war.
  • I didn't know the ISS had such a big despun platform. On uncrewed satellites, despun platforms have historically been a source of catastrophic failures. If the bearing suddenly locks up, the whole satellite starts spinning wildly out of control. I assume the ISS wasn't designed so that the failure of this bearing would kill eveyone aboard, but then what does happen if it fails? The article in today's NY Times says there are backup motors, but how does a backup motor help you if the bearing completely seizes

    • Re: (Score:2)

      by Alioth ( 221270 )
      It only moves at 4 degrees per minute - if it suddenly stops, it's not going to result in "wild tumbling".

    • Re: (Score:2)

      by AJWM ( 19027 )
      I didn't know the ISS had such a big despun platform.

      It doesn't. ISS is not spin-stabilized. Mostly it's gravity-gradient stabilized with gyros and thrusters to make up the difference. The rotating joints are to keep the solar panels pointed towards the sun while the station is at some other angle. In theory they probably don't need to do more than one rotation per orbit, although I'm sure they can rotate much faster than that.

      But nothing like the several RPMs of a spin-stabilized satellite.

  • Consider two metal objects in contact in a mechanical joint. On Earth, joints and other moving parts are typically lubricated to reduce friction. Also, the oxygen in the Earth's atmosphere oxidizes many metals spontaneously, forming a thin passivation layer of metal oxide on their surfaces (for instance, see aluminium oxide). In a hard vacuum, lubricants tend to evaporate or otherwise disappear, and no oxygen is present to create oxide layers. Due to the lack of separating lubricant or oxides, the lattice s

    • 1. part of the mechanical joint sticks together
      2. moving the joint tears the metal
      3. the sharp edges create shavings
      4. ???

      5. PROFIT!!!

      There, finished that for you

  • TFA says "The astronauts have spare parts for the joint with them in orbit."

    What? Another space station up on cinder blocks in the front yard?

    But seriously, TFA says that the joint is 10 feet in diameter. And those panels look pretty big to be just left floating around while they strip the gearbox down and put in new bearings or whatever. Wouldn't they be better off bringing a new panel/joint combo up on the next flight, folding the old one up and swapping the woule assembly?

  • I thought of this [space.com] when I read about the joint damage. As far as I know they never found the source of the crunching noise.

    It could also be something as mundane as a bad heat treat in a bearing leading to launch-load brinelling and subsequent low cycle fatigue. Or maybe they got the launch loads wrong because something resonated and that caused the damage. Or something could have been assembled too tightly.

    What I'm curious about is how the metal chips got on the outside of the thing, I would have thought

  • Just vacuum out the joint.

    Oh. Never mind.
  • Currently #2: http://end-times-hoaxes.blogspot.com/ [blogspot.com] from http://www.google.com/search?hl=en&q=%22hoaxes+exposed%22 [google.com] Google, God's angelic warrior in Illuminati End Times - Information Highway Parallel Lanes - Traffic Jam in the Lane to Hell... http://end-times-information.blogspot.com/ [blogspot.com]

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