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NASA Space Science

More Solar Panel Problems For ISS 118

Posted by Zonk
from the getting-a-bit-shadey-up-here dept.
rufey writes "This week there have been two pieces of bad news from the International Space Station. First was the discovery of metal shavings inside a problematic rotary joint used to keep one set of solar panels in the optimal position for power generation. At the close of a subsequent spacewalk, after it was relocated to its permanent location, the unfurling of the 4B solar panel resulted in it tearing in two places. A spacewalk is now planned for November 4th to attempt to fix the tear. The upcoming spacewalk is not without risks, including the remote possibility of electrocution since it is impossible to stop the solar panel from generating electricity during the repair attempt. NASA says the ripped wing needs to be fixed or the solar rotary joint problem solved before any more shuttles can fly to the space station and continue construction. With a hard deadline of 2010 for Shuttle retirement, NASA does not have much wiggle room in the schedule in order to finish ISS construction."
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More Solar Panel Problems For ISS

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  • by Anonymous Coward on Friday November 02, 2007 @01:55PM (#21214757)
    Why don't they do the repairs at night?
    • Or rotate the panel so that it is side-on to the sun?
      • Because.... (Score:3, Insightful)

        by iknownuttin (1099999)
        Because there's shavings in the rotary joint?

        If there were an easy way to fix this, NASA would have figured it out. Don't forget, these fix rovers millions of miles away by changing computer code. I'm sure any suggestion here on /. has been thought of already.

        • Re: (Score:3, Interesting)

          by Hemogoblin (982564)
          I think you're confusing the rovers with Deep Space 1 [wikipedia.org] and it's Star Tracker.
          • It doesn't matter. My point is the NASA folks are pretty bright people who have the ability to fix their stuff. And it amazed me that they can fix their stuff from a distance by changing computer code - regardless of what project it was.

            And I know there's going to be a ton of posts implying that the NASA folks should have thought of [insert idea here]. Of course they did.

            • And I know there's going to be a ton of posts implying that the NASA folks should have thought of [insert idea here]. Of course they did.

              While I largely agree with all you've said here... Sometimes people just don't think of things, no matter how bright they are. Case in point: an actual phone call I received at 1:30 AM the other day -- "the dishwasher is stuck on and we can't figure out how to stop it". My response: um... just unplug it? "oh, heh, yeah, okay." This was from a grad student (physics) working for me part time. She's very bright and generally has practical skills too. Sometimes people just don't think of things.

              Now, having sai

              • by Shakrai (717556) *

                She's very bright

                No offense, but I don't think you can apply "very bright" to someone that didn't think of unplugging an electrical appliance on their own......

                • Sure you can. I've known everyone from Joe Sixpack to Ivory-Tower Intellectuals and in-the-real-world problem solvers to make stunning displays of stupidity, such as not unplugging an appliance, or walking away from an ATM without the money, or simply forgetting to have breakfast AND lunch and suddenly feeling hungry at 3pm and not knowing why.

                  Actually, I'm kinda hungry right now.
                • Re: (Score:3, Informative)

                  by pintpusher (854001)
                  brightness is irrelevant to whether someone happens to have the right synapses fire in the right order to solve a particular problem.

                  And that was my point. Just because someone is bright, doesn't mean they will automatically think of every solution to a particular problem. Intelligence is not a free pass to discovering stuff (though it helps a lot!).

                  In the case of this particular example, she had done several other things in an effort to solve the problem, any number of which were potentially viable solutio
                  • Re: (Score:2, Funny)

                    But don't you feel like an idiot watching your wheel bounce down the road.

                    "You picked a fine time to leave me, loose wheel..."
                    • by karnal (22275)
                      Apparently no one is a fan of Kenny Rogers - or his brother, Renny Kogers.
                • Re: (Score:3, Insightful)

                  by fbjon (692006)
                  The plug might be behind the dishwasher, in which case it is not immediately obvious, and definitely not a trivial solution.
              • by webrunner (108849)
                One thing, is that someone coming from a computer or engineering background will hesitate to have "just unplug it" as a good suggestion, due to the possibility of interrupting the process causing a catastrophic failure.
        • by Epsillon (608775)

          Because there's shavings in the rotary joint?
          That's a different panel. This one "just" has the two tears. The wing with the dodgy bearing is on the other end of the ISS.
        • by Rolgar (556636)
          I guess that's why we've never lost an astronaut, Oh wait. . .

          NASA has made errors that have killed people by ignoring somebody who got it right. Of course, the original question about working while the station was on the dark side of the earth forgets the fact that the station rotates earth in less than an hour, and few spacewalks last fewer than 3 or 4 hours.
        • by Martin65 (166012)

          Because there's shavings in the rotary joint?

          The solar array with the metal shavings in its rotary joint (starboard side) is not the solar array that they are going to attempt to fix tomorrow (port side). The port side solar array rotary joint (SARJ) is functioning properly, but cannot be rotated because the damaged solar array is not fully extended, and doesn't have the proper rigidity for movement.
        • Re: (Score:1, Interesting)

          by anexkahn (935249)
          That is dangerous thing to say...It's that kind of thinking that stifles innovation...There may be an easy fix that Nasa has not thought of....like maybe covering it up the Solar panel with a blanket. who knows...
      • Re: (Score:3, Informative)

        by Boilermaker84 (896573)
        The panel cannot withstand the stress of rotation while the tear exists. The spacewalk will repair the panel to the point where it can be fully extended. Once fully extended, the tension on the panel helps it withstand the stresses of rotation.

        The damage to the joint affects the opposite panel.
      • The solar panels were designed to generate power from illumination either on the front or the back (although they are not as efficient when back-illuminated.) This allows the panels to gain a bit of power from albedo illumination (i.e., light reflected from the Earth). So turning them backside to the sun wouldn't stop them from generating power.
        • by corsec67 (627446)
          Hence I said "side-on".

          But, the stabilizing wires are tangled in the array, so moving at all (apparently) will tear it more.
    • Why didn't they take up a big blue tarp, to cover the panel and shut it down? Better yet, why not take up a big space blanket, which would be lighter and provide better shade?

      As for why they can't just wait for night, the period of the ISS orbit is about 93 minutes [wikipedia.org]. They'd have to work fast.

      • by davmoo (63521)
        Because the tears in the panel happened while it was being re-deployed on this flight. When the shuttle launched, there was no tear to be repaired, hence no need to carry tarps, space blankets, duct tape, or anything else intended to repair a panel.
        • Re: (Score:3, Funny)

          by AndersOSU (873247)
          If NASA ever goes up into space without duct tape, I've lost all faith in the space program.
          • Re:Blue tarp? (Score:4, Interesting)

            by megaditto (982598) on Friday November 02, 2007 @04:08PM (#21216777)
            Normal duct tape is probably frozen solid at 5 kelvin (or whatever the temperature is at that altitude).

            In fact, I seriosly doubt that any non-magnetic glue will work well at that temp.
            • Oh? [ducttapeguys.com]

              I remember reading about a few of these when they happened... This is the first I've heard of Kapton tape, ("The tape is like duct tape but slippery and able to withstand both frigid cold and fiery hot temperatures."), but it looks like duct tape has played it's role in a number of ways for NASA.
      • Re: (Score:3, Interesting)

        by camperdave (969942)
        Apparently [heavens-above.com] due to the inclination of the orbit, only about a quarter of those 93 minutes is in the Earth's shadow. So, the bad news is that they get slightly less than 25 shock free minutes to fix the problem. The good news is they get 15 attempts per day.
      • Actually, they should push the shuttle launch ahead, and when the shuttle is close to the ISS, have it move in front of the panels to block the sunlight. Then someone can repair the panels without fear of being lit up like a christmas tree, as well as the possible use of both the ISS and space shuttle arms for assistance.

        Please note I'm not taking any arcing effects into account here.

    • Because the night isn't very long on the ISS. From http://en.wikipedia.org/wiki/ISS [wikipedia.org]: "...completing 15.7 orbits per day".
    • Shouldn't he be in a spacesuit when he fixes it therefore shouldn't it be extremely well insulated?

      I mean, the Emperor from Star Wars should be able to blast cosmic rays at him and he should just shrug it off like morning dew.
    • Since they are in orbit and the orbital period is about 93 minutes they only have about 40 minutes "night". Why is night not evenly split between "night" and "day" is because of the when you are in orbit the extra altitude keeps you out of earth's shadow for a about 10 minutes. This is similar to if you are on top of the mountain you will notice the ground below get darker before you do and if you are in a nearly 200 miles above the surface of the earth that extra sunlight time more that a few minutes. Sin
    • by Anonymous Coward
      Mod parent insightful, not funny, as it is valid question, and was indeed asked ("why not limit the the repair time to night passes") on yesteray's NASA's mission status briefing. The response was that sacrificing basicly spending half of the spacewalk to do nothing is not worth the added safety - note that the 'electrocution' mentioned is very extreme case, as the panels itselves are coated with insulation, the tools are insulated etc, but as they spend years in space and were damaged, there is concern tha
    • On a more serious note, don't the solar panels have switches to disconnect them from each other? They are like batteries connected in series, so you just need to break a few connections to lower the voltage and make each subset electrically floating with respect to the others. It's like when you were little and connected a bunch of 9V batteries together and got a big shock.
    • Because NASA Needs A Solar Array... and they are afraid of 30-Days-of-Night.... (Didn't want Halloween to become Hell-O-Ween?)
    • Why don't they do the repairs at night?

      Silly, the astronauts would be asleep at night. :-P

  • Deadline (Score:5, Interesting)

    by ktappe (747125) on Friday November 02, 2007 @02:00PM (#21214855)
    Why is 2010 such a "hard" deadline? Was it not created solely by politicians who wanted to divert resources to go to Mars? As such, can it not be moved just as easily as it was created? It is, after all, three years away. If we can't move deadlines that far out, isn't there a chance we're overplanning, and leaving ourselves completely vulnerable to unexpected circumstances, exactly like this solar panel issue?
    • Re: (Score:2, Funny)

      by iknownuttin (1099999)
      Why is 2010 such a "hard" deadline?

      Because they missed 2001.

    • by GreggBz (777373)
      Remember "Man on the Moon by the end of this decade?"

      Nothing motivates like a deadline. It may seem arbitrary, but NASA is doing lots of good, hard work on the ISS these days, and I think maybe that's because the pressure's on.
    • Re:Deadline (Score:5, Informative)

      by DerekLyons (302214) <fairwater AT gmail DOT com> on Friday November 02, 2007 @02:16PM (#21215107) Homepage

      Why is 2010 such a "hard" deadline? Was it not created solely by politicians who wanted to divert resources to go to Mars?

      No, it was created by the CAIB subsequent to the loss of Columbia.
       
       

      As such, can it not be moved just as easily as it was created?

      No, because the CAIB requires the vehicles be recertified to extend their lives beyond that date - a very expensive and difficult process.
       
      That being said - another limit, currently, is contractural. NASA has only contracted for so many External Tanks, SRB refurbishments, etc... Unless Congress coughs up more money (and approves the delays in converting facilities to support Ares/Constellation - I.E. more money) it simply isn't going to happen.
       
       

      It is, after all, three years away. If we can't move deadlines that far out, isn't there a chance we're overplanning, and leaving ourselves completely vulnerable to unexpected circumstances, exactly like this solar panel issue?

      NASA routinely plans from 3-5 years out, to a decade or more. This is made necessary by the fact that planetary launch windows, if missed, may not recur for two years (Mars) or two _centuries_ (Pluto). Also, the hardware takes from months to years to assemble, on top of months to years of design and review effort. Training for a flight takes months. The Shuttle also has to be overhauled so often, a process taking months, so you have to plan ahead to make time available for that. Etc... Etc...
  • by sgv-0027 (1183425) on Friday November 02, 2007 @02:02PM (#21214903)
    Of course it's going to be the really shiny "NASA" kind, but still duct tape.
  • by RealGrouchy (943109) on Friday November 02, 2007 @02:05PM (#21214933)
    He will not be electrocuted, or at least if he is, he will survive.

    Of all the crewmembers aboard the ISS/Space Shuttle, Parazynski is the most experienced.

    If NASA were going to kill off a character, they'd send out one of the junior redshirts to do the repair job.

    - RG>
    • He will not be electrocuted, or at least if he is, he will survive.

      By definition, electrocution means death. It is one of those misused words of the English language.
      • by G Fab (1142219)
        either that or the language has changed and the people who think they can decide what the english language is are being stubborn.

        Language isn't something you find in a book.
      • D'oh!

        Thanks. In that case, I guess that makes "if he is, he will survive" a pretty big "if"!

        - RG>
      • Re: (Score:3, Funny)

        by BytePusher (209961)
        By definition, electrocution means death. It is one of those misused words of the English language.

        What's a better word that leaves no ambiguity? Shock, needs to be specified and the wording will be awkward as it sounds odd to say he will be "electrically shocked," or could experience "electric shock." The etymology of the word from dictionary.com says is came from "electric" + "(exec)ution." It's clever, because it provided nearly an instantaneous and seamless integration into the English language since e
      • by khallow (566160)
        I can't believe the ignorance I'm seeing. What planet did you crawl out from under? The original poster indeed means electrocution as in death. But of course, it'll be for dramatic tension. They'll try out the risky alien technology. And after a suitably cinematic light show, he'll wake up as good as new. After all, they're up to their eyeballs in deux ex machinas and mcguffins.
    • by davidsyes (765062)
      So, will he return to Earth as V'Ger? Or, will he come back as Nomad, seeking one Jackson Roykirk. In either case, he'll probably return to "eliminate carbon-based infestation"... Yikes... Is this a job for Shatner, or will he just holler "Khhhaaaaannn!"?
  • D'oh! (Score:4, Insightful)

    by PHAEDRU5 (213667) <instascreed@g[ ]l.com ['mai' in gap]> on Friday November 02, 2007 @02:10PM (#21215023) Homepage
    Good luck to them. I hope all goes well, the repair is made, and nobody gets hurt.

    That bit about not being able to take it down for repair, well, that's going to make it into some future book on industrial design. Oh, and into future space stations. I hope.
    • Re:D'oh! (Score:5, Insightful)

      by everphilski (877346) on Friday November 02, 2007 @02:31PM (#21215335) Journal
      That bit about not being able to take it down for repair, well, that's going to make it into some future book on industrial design.

      Pray tell, short of covering the solar array from view of the sun, how do you stop solar cells from generating electricity? It is a passive electricity generating device, not an active one (like a fuel cell or a conventional gas-powered generator). As long as it has a sufficient view factor of a light source, it generates electricity.
      • by PHAEDRU5 (213667)
        I think you just answered your own question.
        • Now tell me a way to cover 138 m^2 of solar array with what you have on station ... now.
          • by PHAEDRU5 (213667)
            Obviously I was talking about the future, not the present.

            You're starting to come across as a complete prick. Did you design the current (as it were) fuckup?

      • You have your transport vehicle (i.e. the shuttle) position itself between the light source (i.e. our sun) and the generation system (i.e. the panels) during repair. Last time I checked, the shuttle had a fairly wide body.
        • The shuttle is docked to the station and will remain there until the end of mission. Undocking and redocking the shuttle is a lengthy procedure. It also has some potential for causing movement of the station, and if they're concerned about exacerbating the damage simply by rotating the joint, then, a less controlled motion due to undocking is most certainly a no-no.

          Conducting an EVA around the ISS with the shuttle in motion is literally placing the astronauts (mass: 200 kg) between a rock (shuttle - mass
      • It's simple. All they have to do is unplug it!

        - RG>
      • Danger from the generated electricity? As I understand it, these panels only have one active side - rotate the sucker 180, point the passive side towards the sun, and away you go?
  • by ackthpt (218170) *

    (An upgrade to Hamlet's rhetorical question)

    We're gonna need a bigger roll of Cello Tape.

  • Electrocution? (Score:3, Interesting)

    by Radon360 (951529) on Friday November 02, 2007 @02:40PM (#21215481)

    including the remote possibility of electrocution since it is impossible to stop the solar panel from generating electricity during the repair attempt

    Forgive my ignorance, but are they going to do this spacewalk repair bare-handed? Is there at least two exposeds part of a spacesuit that is conductive from the outside to the inside (you need two points to complete a circuit)? If there's something like aluminum ring seals at the wrists, have another crewmember double wrap them with duct tape or electrical tape before sending them outside.

    How does electrocution come into play with this? Dielectric breakdown through the suit shouldn't be an issue as I seem to recall on a previous story that we're talking roughly 160VDC potential, nearly the same as US household wall socket voltages. Deadly? Yes. Arc through your spacesuit (twice)? Hardly.

    • Re:Electrocution? (Score:4, Informative)

      by rbarreira (836272) on Friday November 02, 2007 @03:15PM (#21216035) Homepage
      Did you read the article?

      Flight controllers have already warned Parazynski not to touch the electricity-generating solar cells that cover virtually the entire wing. If the metal of a tool he was holding melted, it could burn a hole into his glove.
      • by Radon360 (951529)

        But wouldn't result in a burn injury or the risk of death due to decompression and not electocution?

        Maybe I'm being too pedantic on the definition of electrocution, which is death from electric shock, not death resulting from some failure caused by an electrical discharge.

        • by rbarreira (836272)
          No, I don't think you're being too pedantic. Maybe this [slashdot.org] is the answer?
          • Yes, that [slashdot.org] is a valid concern, but that is not from TFA [msn.com]. In fact, the only mention of electrocution comes directly from the slashdot editor's/submitter's summary:

            including the remote possibility of electrocution since it is impossible to stop the solar panel from generating electricity during the repair attempt.

            The above quote rather explicitly attributes the danger of electrocution from electricity being generated from the solar panel, not the discharge from static build up.

            The short of it (no pun intended): Electrocution from the electrical current from the solar array? No. Electrocution due to a static discharge? Possibly yes, but it's not the

    • by OdinOdin_ (266277)
      Gee... while it might not electrocute the astronaut, it might zap his space suit control system and his life support, or conduct down the robot arm boom he is standing on and end up taking out a system in the ISS (or the robot arm itself). Its a very real danger for everyone up there.
    • 160VDC potential, nearly the same as US household wall socket voltages.
      DC is as different from AC as black is from white black white black white black....
    • by Agripa (139780)
      There is a significant environmental difference when you deal with powered circuitry in a vacuum verses an electrically insulating atmosphere. The space station not only travels through a good vacuum but any gases present will tend to be an an ionized state and conduct so it is not necessarily a matter of avoiding physical contact from the panel to a conductive area of the space suit.

      I suspect the best defense would be a conductive suit similar to that worn by linemen who work on power lines. I do not kno
  • by digitaldc (879047) * on Friday November 02, 2007 @02:47PM (#21215603)
    The partially unfurled solar wing is producing power, and there is no way to turn it off

    Man, do we need one of these things on Earth, RIGHT NOW!
  • Simple solution: make sure his tether is non-conducting. Use one of those MMUs so the astronaut can be autonomous instead of on an umbilical. Or am I overlooking something?
    • Re: (Score:3, Informative)

      by Zerbey (15536)
      The fact that the MMU hasn't existed for over 20 years? NASA discontinued the project as being too risky with little benefit.
    • Even better - route all the power from the solar array through the deflector dish! That way there won't be any power left to electrocute. It always worked on Star Trek...
      • by tylernt (581794)

        Even better - route all the power from the solar array through the deflector dish!
        That only works if you polarize the plasma conduits and invert the tachyon beam though.
    • The panel contains both the charged and grounded elements required to induce current, it is only necessary to get a hold of each of those sides (such as grabbing exposed conductor in both hands) to make a perfect circuit across your chest. It only takes something less than 1 Amp to stop the heart IIRC. As the previous post said, though, the risk is minimal and these things are done to the limits of safety (we hope).
  • Electrocution? (Score:1, Redundant)

    by syukton (256348)

    The upcoming spacewalk is not without risks, including the remote possibility of electrocution since it is impossible to stop the solar panel from generating electricity during the repair attempt.
    So they can't just turn the panels away from the sun...why? Or unfurl some sort of mylar shield? What kind of amateurs designed a system that can't be turned off for maintenance?

    • by Anonymous Coward

      Jerkoffs from Lockheed Martin designed these problem-plagued arrays. Furling/unfurling the arrays has been a problem from day one. Recall the problems the HST had with array warping? They were designed by the same idiots at Lockmart. The problems went away after the last shuttle servicing mission when NASA installed proper rigid Boeing arrays.

    • by maciarc (1094767)
      Can't they do this at night? I don't know of an orbit that would have them in daylight 100% of the time.
      • by tylernt (581794)

        Can't they do this at night? I don't know of an orbit that would have them in daylight 100% of the time.
        Apparently is is possible to "ride the terminator" in a Sun Synchronous Orbit [wikipedia.org] so you always see the Sun, but the ISS isn't in such an orbit.
  • and doesn't touch ground with the other, he should be fine. Wait, how does one ground himself while in space?
    • I would assume the same way you ground something in a car, which is isolated by rubber tires: a large mass of metal, usually the body or engine (or both), serves as the ground.
      • by ookabooka (731013)
        Ok, to add a bit to your point there. The entire chassis of the car is ground. You have your battery, with two terminals. The positive terminal is connected to the electronics that need power, and the negative terminal is connected to the chassis so all you have to do is have your electronics tie down to some part of the chassis for ground instead of running two wires. This also has useful applications in terms of noise reduction but I'm not gonna get into that. You do raise an interesting point though, dep
  • At the rate things normally break and the lack of a budget for replacement parts, exactly what do they expect to work in 2010 when construction ends?

  • If any of the astronauts get seriously shocked or even killed, NASA managers are going to wish they had followed basic electrical safety precautions in an industrial environment, which the ISS is...

    Lock Out and Tag Out electrial safety procedure - something NASA should be following - imagine the public and political outrage, if someone is seriously injured / dies as a result of skipping some basic safety precautions like turning off that solar array...

    http://en.wikipedia.org/wiki/Lock_and_tag [wikipedia.org]

    While it's true
    • Re: (Score:3, Informative)

      by Anonymous Coward
      If you read the article, in fact if you had merely completely read the summary, you would understand that solar panels can not be turned off. Even in the absence of direct sunlight (which only occurs for a maximum of 36 minutes each orbit) they will still develop some power due to reflected light. You would also have noted that electrocution is a "remote risk."

      If the problem were anywhere downstream of the sequential shunt units, they could lockout/tagout (btw, there is no OSHA in space), but it's upstre
  • Many here voice their opinion that the space station os a waste of money. This solar panel incident has vindicated the ISS supporters: Testing such technologies in low earth orbit is a needed. You would not want to experience that on an interplanetary flight.

    We may not necessarily develop new technologies but engineers can test solutions "in the field" and hone the skills needed to develop working solutions for voyages where no rescue/repair is possible.
  • "...since it is impossible to stop the solar panel from generating electricity during the repair attempt..."

    -Er... Houston, we have a problem
    -What is it now?
    -you idiots forgot to install the fuse box

Save yourself! Reboot in 5 seconds!

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