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Space Power Science

ISS Goes Solar 176

SumDog writes "The international space station's newest power source, a set of solar wings, made its debut yesterday. The solar array is part of a new 17.5-ton space station segment that was connected to the orbiting outpost during a spacewalk Monday."
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ISS Goes Solar

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  • by WrongSizeGlass ( 838941 ) on Wednesday June 13, 2007 @07:32PM (#19499085)
    ... solar power finally working its way into our everyday lives.
    • by malsdavis ( 542216 ) on Thursday June 14, 2007 @12:12AM (#19501111)
      I'd like to know the realistic reasons why solar power isn't far more prevalent as a source of power generation, particularly on a local/household scale. Why are solar panels still so expensive?
      • Re: (Score:3, Informative)

        by bryan1945 ( 301828 )
        From what I've read (not a whole lot), the basic photo-electric conversion process is just not that efficient. Something about the solar power knocking electrons out of place, creating a current between the displaced electron and the hole it left. The problem is that the electron quickly falls back. I believe current research is focusing on materials that either 1) remove the electron further or 2) somehow keep the electron from falling back as quickly.

        It's 3 AM and I'm doing this from memory, so take it
      • by p0tat03 ( 985078 )

        Cost of manufacturing mostly. Unfortunately not everything that ought to be cheap is, or could be.

        I know there has been some very good work done recently by some companies that I know in terms of improving panel efficiency. Right now the amount of roof real estate you have to cover + the cost of installation simply doesn't break down *that* well for the average homeowner with not a great deal of cash to blow.

        Hopefully with improved panel efficiency, people can either power their homes with smaller (and

      • The silicon used in solar panels is expensive. Also, another reason for the cost is installation cost of the panels.
        However, solar panels are subsidised in many places, for several reasons: they produce electricity when demand is highest, in places with clear sky all year long their production is constant (with very slow variations - compared to the tens of minutes a slow changing power plant will allow).
        When the production was very limited, bad silicon from micro
        • Interesting article here talks about how the costs for silicon for solar panels are higher than they need to be, because although it doesn't have to be as pure as semiconductor silicon, there's no process for making it at that lower grade of purity.

          "The problem for the PV customers for silicon is that they are a fast grower sandwiched between two mature sectors growing roughly in line with the economy. Bulk silicon is used in old-economy alloys and sealants; and while demand for semiconductors grows rapid

      • Re: (Score:3, Interesting)

        by dino213b ( 949816 )
        At the risk of being called a troll, I will bite again.

        The real reason is lack of government support. Large scale public projects can rarely succeed until they receive government subsidies. In other words, 300,000,000 Americans all need to pitch in so that a large project can make it. As a prior proof of this, consider hydroelectric (and irrigation system) dams in America. They were privately funded prior to USACE/Bureau of Reclamations taking over and during that period they all failed - economically s
        • Re: (Score:3, Informative)

          by OrangeTide ( 124937 )
          So we pay the power company and they profit, then we have to pay higher taxes to fund a project because the power company was not willing to invest their profits into turning the technology into something cheaper? You'd think if the power company could produce cheaper energy they could

          Hydropower is proven to be cheap, even though the initial investment is quite large. And building them is an engineering feat, rather than a technological breakthrough. At the time we built dams we were doing very well with fe
        • The government can make anything "successful", if you don't mind subsidizing it with tax dollars. What does this prove? Nothing at all.

          The whole strategy of picking specific technologies to subsidize is wrongheaded anyway. If the goal is to produce cleaner power, or reduce dependencies on nonrenewable resources, then the government should tax pollution and nonrenewable use appropriately, and then get out of the way and let the market allocate resources. Governments are good at taxing; markets are good at

      • Profit vs. Cost

        It takes the same amount of silicon substrate and a whole lot of really cutting edge technology to make a super-efficient solar sell --like they use in the ISS-- that are literally worth their weight in gold-- which then outputs power at about a 3:1 factor over the cheap "thin film" chips. The cost of a thin film solar array to fully power one house is only about double the cost of buying electricity from the power company for 10 years.

        So it isn't economically viable especially considering

    • We turn our water heater off for 60% of the year; we've some cheap (GBP 5000) panels on the roof that give nice hot water even when the skies are cloudy (they take their energy from IR, not visible light) and they even carry on working when the grid's out (we live in the middle of a forest, and trees grow branches specially to drop on the lines several times a year.) In fact as luck would have it we had a power cut at 8:15am this morning, just as I was getting up, and lo! I was still able to wash in hot wat

      • You should be careful with PV panels. If your house is shaded by trees, even a small, sharp shadow on part of a panel will drastically reduce its output. Make sure that you consult a good PV installer/dealer/someone who really knows his shit before you buy a ton of panels and inverters and stuff.

        As for wind, you'll have to put the turbine well above the tops of the trees to get out of the turbulent airflow. Also, the bigger the turbine, the slower the blades turn, and the less noise is generated. Bigger
  • Wait... (Score:5, Funny)

    by kmac06 ( 608921 ) on Wednesday June 13, 2007 @07:39PM (#19499149)
    So the one place where greenhouse gas emissions don't matter uses renewable energy? :P
    • Re:Wait... (Score:5, Insightful)

      by rednip ( 186217 ) on Wednesday June 13, 2007 @07:48PM (#19499239) Journal

      So the one place where greenhouse gas emissions don't matter uses renewable energy?

      If you think that the price of gas is expensive at the boat dock, you should see the bill for delivering a tankful 200 miles in the sky.

      • Re: (Score:2, Interesting)

        by joek1010 ( 980753 )
        And you have to send the oxygen too. Its tough to make green house gases without any oxygen rich environment to burn it in.
  • Off Grid? (Score:5, Funny)

    by QuantumRiff ( 120817 ) on Wednesday June 13, 2007 @07:40PM (#19499153)
    So when do they get enough Solar Panels to go "Off Grid"?


    Thank you, I'll be here all week!
  • Well (Score:4, Informative)

    by rbanffy ( 584143 ) on Wednesday June 13, 2007 @07:41PM (#19499161) Homepage Journal
    Didn't the ISS already run on solar power?

    I mean... Tree-huggers everywhere would have been screaming for years if it did run on nuclear (and, quite probably, we don't have the required technology anyway).
    • Re:Well (Score:4, Informative)

      by Jugalator ( 259273 ) on Wednesday June 13, 2007 @07:42PM (#19499173) Journal
      Yes, it did, but now it has more power than ever before!

      To give sufficient power for the upcoming components and experiments.
    • by Fuji Kitakyusho ( 847520 ) on Wednesday June 13, 2007 @08:01PM (#19499381)
    • by dedazo ( 737510 )
      Solar panels in near orbit have never been a problem, because for all practical purposes the orbital platform is exactly at the same distance to the sun than the surface of the Earth.

      Interestingly enough, NASA has already unveiled plans for a deep space probe called Juno [] that will use solar panels exclusively for the first time ever. Apparently they've become so efficient that the enormous distance to the Sun ceases to become a problem. This also bodes well for civilian uses of solar panels, I imagine. He

      • Re:Well (Score:4, Funny)

        by Dunbal ( 464142 ) on Wednesday June 13, 2007 @09:54PM (#19500201)
        Apparently they've become so efficient that the enormous distance to the Sun ceases to become a problem.

              Or at least that's what the manufacturer says. And if you had a $40 M contract you'd say the same. We'll only really find out in 30 years when the guy in charge of the probe suddenly goes "where the hell did my probe go?" one Wednesday morning.

              All your voltage are belong to us.
      • Re:Well (Score:5, Insightful)

        by confused one ( 671304 ) on Wednesday June 13, 2007 @11:12PM (#19500779)

        Juno is slated to go into Jupiter orbit. Solar may be useable out to Jupiter. The panels have to increase in size proportional to the distance from the sun squared... The weight increases exponentially. To reach past Jupiter it becomes impossible (practically) to launch that much mass from the ground. If you want 1kW of power at Saturn or maybe the Kuiper belt you have to use nuclear. If Voyager 1 and 2, launched in 1977, were powered by solar, even using these new panels, we would not still be receiving telemetry from it. Voyager 1 is currently is currently 18 times farther from the sun than Jupiter. Voyager 2 is currently 15 times farther from the sun than Jupiter. Both are studying the boundary of our solar system.

        Yeah, I suspect much of the advances in solar technology have come out of NASA's budget. This is the kind of area where NASA and DOE spending feeds back obvious results.

        I get frustrated as well when people protest launching nuclear powered spacecraft. The probability of an accident is extremely small. The probability of that accident affecting populated areas is smaller. The effect would be insignificant barring an explosion at the launch tower; and, that would be contained to the area around the base. If people are going to make the argument against, I wish they would do it with real numbers. If you're going to argue that "it's bad" then show me how bad and show me how that level of "bad" compares to the safety standards...

        I do like this link easurement.jpg []
        • > "The panels have to increase in size proportional to the distance from the sun squared..."


          > "The weight increases exponentially."

          Really? I always hate it when people abuse the term "exponential", but given that you're speaking in a scientific context I think you are probably using its intended meaning. So then, I'll ask why does it increase in that way? Why not some form of polynomial growth? Also, when you say weight, do you mean mass? If not, then with respect to what body or system?
        • In response to my own comments above: I can understand the mass increasing exponentially if you're talking about nuclear fuel, as the rules of nuclear decay naturally involve the exponential function, but you were talking about solar panels, where the intensity only drops off polynomially. Did you mean to refer to nuclear fuel instead?

          Also, according to wikipedia ( lectric_generator []), RTGs on previous spacecraft generate somewhere in the neighborhood of under
      • by rbanffy ( 584143 )
        "there's a 1:100,000,000 chance that it might cause contamination"

        So, there is a pretty good chance we will never again see those nasty radioactive pollutants...

        Treehuggers everywhere should be happy for this!

        But, again, if we are talking manned spaceflight reliability, I would say between a 1:100 (shuttle) and a 1:200 (soyuz) chance it goes _very_ wrong. And we know unmanned has a higher tolerance to catastrophic failure.
    • Nuclear power makes sense in the outer solar system and it is used there for unmanned exploration. It makes little sense in the inner solar system where the Sun's power is easier to harvest. The whole thing is about launch mass. At the distance of Saturn you need about 100 times more in solar panels for the same power so nuclear power becomes competitive.
      Apropriate technology for the third rock: s -selling-solar.html []
    • by dbIII ( 701233 )
      Since we are talking about kilowatts there is no practical nuclear solution. Nuclear "batteries" work by using the photoelectric effect anyway, weigh a bit and you would need a lot of them - and steam power is just a little bit too heavy for space and overkill when you don't need gigawatts.

      Since a few seconds thinking like an engineer or physicist rules this out - how did a nuclear troll who mentions their favourite energy whenever electricity gets mentioned get modded insightful?

      • Newer nuclear "batteries" use the Seebeck effect as distinct from the photoelectric effect as used in nuclear systems in satellites that spend time in low orbits such as the Kosmos series (no panels can be used if you touch the atmosphere at high speed once per orbit to get nice close photos). However, you are still talking about watts for a relatively heavy unit as distinct from kilowatts required and more easily obtained from solar panels if you are just going to be in an earth orbit where you don't have
      • by rbanffy ( 584143 )
        These days, sarcasm is both insightful and informative ;-) Sorry, but you have to deal with it. I expected a funny mod, but, ok... You never know which way the public will mod you. And no, nuclear fission is not my favorite power source. It's just that saying the ISS is "going solar" implies it went in another direction before. Something it, obviously and conspicuously (its solar panels already made it visible from the surface), didn't.
    • > "I mean... Tree-huggers everywhere would have been screaming for years if it did run on nuclear"

      Hell, that's nothing. Tree-huggers will scream no matter what you do. I was shocked to learn in my Science Technology and Society class that there were actually assocations of people dedicated to fighting wind power. Wind for God's sake. Apparently it wasn't slick-looking enough for them (ruined their precious landscapes) and was a hazard to birds (true in some cases, but just propaganda with larger 5 MW gen
      • by dylan_- ( 1661 )

        I was shocked to learn in my Science Technology and Society class that there were actually assocations of people dedicated to fighting wind power. Wind for God's sake. Apparently it wasn't slick-looking enough for them (ruined their precious landscapes)

        What kind of shithole do you live in that it wouldn't be ruined by the appearance of 180 butt-ugly, 300 foot high towers? Did you ever consider that it might be the people who actually live there who might object to this? Especially when tourism is one of t

  • by camperslo ( 704715 ) on Wednesday June 13, 2007 @07:42PM (#19499169)
    ...a giant shade to reduce global warming
  • by Anonymous Coward on Wednesday June 13, 2007 @07:43PM (#19499189)
    • Re: (Score:3, Funny)

      by Anonymous Coward
      No, a really long extension cord. Kept getting tangled on Everest though.
    • Re: (Score:3, Funny)

      Astronauts on the ISS have to train each day on those bicycles. Now you know why...
  • Here's a real link. (Score:5, Informative)

    by pavon ( 30274 ) on Wednesday June 13, 2007 @07:50PM (#19499253)
    Here is a link to a story [] with a little more content and pictures of the new unfurled solar panels.
  • by Nymz ( 905908 ) on Wednesday June 13, 2007 @07:52PM (#19499275) Journal
    During the installation, one the navigation computers had a glitch that caused false fire alarms and a loss of gyroscope control, which sent the station spinning [] out of control. Only thanks to a hack were they able to bypass the Russian functions, and get the gyroscopes working again.

    If the station couldn't align the solar panels toward the sun for each days charge, then it would only be a matter of time before the batteries died, and without power nothing on the station will work, nothing.
  • The international space station's newest power source, a set of solar wings, made its debut yesterday.

    Glad to hear it. That 200-miles-long extension cord [] was becoming a real hassle!
  • The new solar panels were unfolded like an accordion window blind, their orange and black colors reflecting the sunlight.

    Is it just me, or are solar panels that reflect sunlight not a good thing?
  • by GreggBz ( 777373 ) on Wednesday June 13, 2007 @08:29PM (#19499589) Homepage
    So why do these stories about NASA, the ISS etc.. so rarely link to

    You can go here [] and get much better, more detailed information about the solar panels, the crew, the rest of the mission, watch live video, etc. Your tax dollars pay for it, you should use it.

    It is the most comprehensive site for news in information regarding, imagine this, NASA. The only instance where it's probably not appropriate is when there is some requirement for investigative reporting, otherwise, things like the Boston Globe are likely to give the watered down, science lite AP version of what NASA tells them.

    • Due to the previous 6 or 7 years of republican stranglehold over the government and diverting all funds from where the nation needs them to pointless, yet strikingly bloody wars, NASA's had to make some budget cuts. In addition to purses for technological competitions that can solve real-world problems, they've had to downgrade from a DS3 connection to an IDSN line.
    • Well, if you think about it, the bandwidth from Nasa is paid by the citizens being taxed; so, instead of linking to a page in which you are charged per view some way or another, they link you to a page full of ads and you don't pay a dime.......or someone just wants a big check from getting the slashdot crowd visiting and viewing (or in some cases blocking) ads.
      • by Dunbal ( 464142 )
        ahhh flashblock. The internet has not been the same since I got it.
        • Flashblock, you say? I should look into some of these plugins for firefox, but I'm just too lazy. Anyway if it does what the name implies, I already have it on some of my browsers, where I just don't bother installing the damn plugin.
    • ...activate the International Space Station's Starboard 3 and 4 (S3/S4) truss segment during STS-117's second spacewalk.

      If you are a NASA news follower then that sentence fragment might mean something to you... otherwise it is nice to have someone rewrite the story for casual consumption, though they should have also provided a link to the source, oh wait... right there at the bottom of the story... a link to, for more information ;-p

  • That's either the most expensive tank of gas in the world or a really fucking long extension cord.
    • Dummy, what do you think they were basing the technology for the space elevator on!?

      The same technology they used on the extension cord they dropped from the station and had plugged into the reactor at NASA in Houston.

      Gosh, if Slashdotters would just RTFA's they'd have known this years ago! :)
      • Dummy, what do you think they were basing the technology for the space elevator on!?

        The same technology they used on the extension cord they dropped from the station and had plugged into the reactor at NASA in Houston.

        Gosh, if Slashdotters would just RTFA's they'd have known this years ago! :)
        Wow, and I thought it was lame when giant mecha ran on extension cords!
  • by Dunbal ( 464142 )
    17.5 tons. I'm thinking about increased amount of propellant needed to keep the ISS in the correct orbit with this new "power source". Yes we can give you more power, but now we need to spend twice as much fuel to keep you in orbit, so your total flight time is decreased by 8 years...

    That's the beauty of physics, everything is connected. And I'm not even a physicist.
    • Re: (Score:3, Insightful)

      by Anonymous Coward
      I agree, you're not a physicist. The mass of the array doesn't at all influence the amount of fuel necessary to keep it in orbit. What matters is its cross sectional area.
      • Re: (Score:3, Interesting)

        by Dunbal ( 464142 )
        Hmmm ok, I'll grant you that (from what I remember from high school) the "g" part of a sattelite in orbit gets canceled out. However I think that the basic laws of motion - specifically F=ma still apply when it comes time to turn on the engine and give the station more velocity to bump it back up into a higher orbit. If m increases and the "a" that I need to increase the velocity is the same, I need more "F", which means a longer burn, which means more fuel.

        I agree that mass has not
        • When you increase something's mass there's a corresponding increase in its momentum. This means that you have to apply a larger impulse to it in order to change its momentum. So yeah, you're right.
    • by AGMW ( 594303 )
      As I posted previously (er ... "DUP") ... Do they generate enough power now to be able to usefully use it in an Ion engine to help keep the ISS on station (or indeed move it further out)?

  • A far cooler aspect. (Score:5, Informative)

    by Lumpy ( 12016 ) on Wednesday June 13, 2007 @09:54PM (#19500195) Homepage
    Check when the ISS will be overhead and illuminated by the sun. You can with a pair of good binoculars and SEE the ISS as a shape now instead of a dot of light with the Panels Deployed.

    Incredibly cool to be able to see something in space and visually identify it.
    • Re: (Score:3, Interesting)

      by Anonymous Coward
      Me thinks you are talking out of your rear aperature

      Its damn hard to image ISS _details_ (even with the shuttle attached) with an 8inch (200mm) telescope let alone a pair of binoculars. I've seen the ISS (with and without attached shuttle) naked eye, thru binoculars (7x50), and an 8 inch Meade LX-90 using a 12mm eyepiece (many times naked eye, many times with the binoculars and a few with the scope). Binoculars (that you can hand hold) are going to show you a blob - a blob which (in my opinion) got more o
    • That's no moon... That's a space station!

      Tired jokes aside, I agree with you that it's very cool to see such things with the naked eye.
    • "Incredibly cool to be able to see something in space and visually identify it."

      Sadly, what that means to me is that the ISS is in a stupidly, worthlessly low orbit which will cause it all-too-soon to fall from the sky as space junk, or require constant orbital booster shots.

      L5 would have made so much more sense, but then the inadequacies of the POS shuttle would have been even more evident.
  • Tax (Score:3, Funny)

    by adrian727 ( 968395 ) on Wednesday June 13, 2007 @10:47PM (#19500605)
    Did they pay fuel tax yet?
  • Does anyone have any idea how efficient the solar panels are? According to the STS-117 Fact Sheet (1.8 Mb PDF) [] on the NASA Space Shuttle [] page the panels generate 60 kilowatts and are 240 feet long. But that doesn't tell us the width of the panels, only the length, so I can't figure out the kilowatts per unit area. Does anyone have more details?
    • Re: (Score:3, Informative)

      by teridon ( 139550 )
      All of the solar arrays on ISS are about the same.

      The dimensions of each panel (total 4 panels per truss) are 111.6 ft x 15.2 ft. Behold ASCII art skillz! (cut, because /.'s fucking lameness filter)

      Source []: "Photovoltaic Power for Space Station Freedom" by Baraona, C.R. in "Photovoltaic Specialists Conference, 1990., Conference Record of the Twenty First IEEE"
  • Now remind me again...what is the ISS for?
  • The ISS is currently suffering a major computer glitch. All three Russian computer systems have crashed, the American systems rely on the Russian ones to work, and all of this could ultimately lead to the life support systems shutting down, loss of attitude control, and a complete evacuation of the ISS until such time a flight to replace the faulty systems can be made. Too many Google News links to provide, so move the mouse and go clicky click for more.
  • Idiots. What will the ISS do on a cloudy day? Didn't think of that, did they?

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