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NASA Space Technology

NASA to Launch Solar Sail 147

arbitraryaardvark writes "Physorg reports that NASA will launch a solar sail around the end of July. It'll be the first of its kind; a previous attempt blew up. It's a small proof-of-concept gizmo, not a full-on spaceyacht. Solar sails operate on photon pressure from sunlight. They are well known to science fiction readers, otherwise not so much." C-net has coverage, too.
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NASA to Launch Solar Sail

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  • Ah, sigh (Score:5, Funny)

    by Gewalt ( 1200451 ) on Saturday June 28, 2008 @12:34PM (#23982863)
    Sadly, my kids think a solar sail is something you put on a wooden ship to power the ion thrusters. Stupid disney and their stupid wooden ships in outer space...
    • Re:Ah, sigh (Score:5, Insightful)

      by ScrewMaster ( 602015 ) on Saturday June 28, 2008 @12:34PM (#23982873)
      Yeah well, Hollywood and science haven't ever mixed well, for the most part.
      • Re:Ah, sigh (Score:5, Insightful)

        by Anonymous Coward on Saturday June 28, 2008 @12:44PM (#23982989)

        "Yeah well, Hollywood and {science, art, engineering, law, philosophy, history, fantasy, ...} haven't ever mixed well, for the most part."

        There. Fixed it for you.

        I'll give you a hint. Hollywood is like a marketing department at an engineering firm. They have learned very well that they don't need to understand the product to sell it. Package a movie with a couple of hunks and babes as well as some explosions and dramatic music, and nobody is going to care about its accuracy.

        • Re:Ah, sigh (Score:5, Funny)

          by neokushan ( 932374 ) on Saturday June 28, 2008 @12:47PM (#23983027)

          Package a movie with a couple of hunks and babes as well as some explosions and dramatic music, and nobody is going to care about its accuracy.

          Well, except sad bastards like us.

        • Hollywood is like a marketing department at an engineering firm.
          A unicorn is what's left of the engineer's rhinoceros after marketing gets done with it.

          • by CptNerd ( 455084 )

            Hollywood is like a marketing department at an engineering firm.
            A unicorn is what's left of the engineer's rhinoceros after marketing gets done with it.

            I always thought it was the other way around...

            Oh wait, that's after upper management gets done with it.

    • Re: (Score:2, Insightful)

      by 0111 1110 ( 518466 )

      Stupid disney and their stupid wooden ships in outer space.

      And stupid children too dumb to even think about questioning any of it.

      • Re:Ah, sigh (Score:4, Insightful)

        by Kjella ( 173770 ) on Saturday June 28, 2008 @03:06PM (#23984323) Homepage

        Joke, right? Because know a lot of science fiction movies that contain some very rotten science, doesn't mean they're bad films only that you shouldn't take it as a science class. I'd rather have entertaining entertainment than accurate yet extremely boring movies. Yes, I know that in space noone can hear you scream but I don't care when the star destroyer comes "whooshing" by. And that most things don't blow up like they were packed with dynamite. If you didn't learn that outside the movies, maybe the problem is that you take all your learning from movies rather than the movie...

        • Re:Ah, sigh (Score:5, Interesting)

          by ricegf ( 1059658 ) on Saturday June 28, 2008 @03:24PM (#23984471) Journal
          In the book "The Trouble with Tribbles", David Gerrold mentioned that an early Star Trek script included three pages of technically accurate dialog between the Good Captain and his crew to get the Enterprise turned to head to the newest monster-of-the-week. Gene Roddenberry scratched out all three pages and replaced it with a single Captain Kirk command: "Turn around!"
        • by bit01 ( 644603 )

          I'd rather have entertaining entertainment than accurate yet extremely boring movies.

          I'd rather have entertaining entertainment with accurate science movies.

          The two are not mutually incompatible like many people like to imply. e.g. 2001. The basic problem is that most Hollywood types are scientifically illiterate, are actively proud of it and don't care that they're not very entertaining to people who are scientifically literate. Many movies are like fingers on a blackboard. e.g. The tilting helicopter in

        • Re: (Score:2, Insightful)

          by Mike610544 ( 578872 )

          Yes, I know that in space noone can hear you scream but I don't care when the star destroyer comes "whooshing" by.

          This always seemed like a weird pedantic objection to me. If your ears were exposed to the vacuum of space you'd have bigger problems than not hearing spaceships. Why not question the fact that there's an all-seeing camera fraudulently providing the visuals?

    • Re: (Score:3, Interesting)

      by Plazmid ( 1132467 )
      What do you mean? Wood has strength to weight ratio similar to that of carbon fiber, however wood is much cheap than carbon fiber. The main reason wood isn't used to build spacecraft is that wood is porous, but this might be solved by vacuum coating the wood with aluminum.
    • Re: (Score:2, Funny)

      by Anonymous Coward

      Funny, that's how you get from Bajor to Cardassia as well.

    • What's worse is they could read slashdot and believe that they work by photon pressure rather than solar winds. What next? Does reentry burn you up because of friction (rather than rapid pressure change)?

    • Sadly, my kids think a solar sail is something you put on a wooden ship to power the ion thrusters. Stupid disney and their stupid wooden ships in outer space...

      The annoying part is that other than that, it was actually a fun movie, but that was a little much. I actually much preferred Titan A.E., which wile not exactly super-realistic, did at least have action-reaction in space.

  • by neokushan ( 932374 ) on Saturday June 28, 2008 @12:36PM (#23982897)

    They are well known to science fiction readers, otherwise not so much

    Excuse ME, I'm MORE than aware of what they are and I DON'T read science fiction.
    .
    .
    .
    .
    .
    Star trek ftw!

    • Re: (Score:3, Insightful)

      by oodaloop ( 1229816 )
      Obviously they weren't aware that one data point nullifies a generalization. Stupid indeed.
  • by Anonymous Coward on Saturday June 28, 2008 @12:41PM (#23982957)

    And in 50 years, the US Post Office will still be using said technology, while FedEx is traversing through worm holes.

    • by DigiShaman ( 671371 ) on Saturday June 28, 2008 @01:09PM (#23983243) Homepage

      while FedEx is traversing through worm holes

      Oh great! So FedEx will now tell me that my package was delivered. The bad news: it was delivered to me in an alternate reality. With my signature to prove it no doubt. Never mind the fact that "I" didn't get the damn package.

      • by Anonymous Coward on Saturday June 28, 2008 @01:27PM (#23983405)
        Meanwhile, UPS will just launch the damn thing into a black hole and say customer service is 'working on it.'
        • by Khyber ( 864651 )

          All while DHL keeps screwing up and sending your package directly to me, and when I send it back they boomerang it right back to me again!

          • by JLF65 ( 888379 )

            That's FedEx where I live. They dropped someone else's package on my front doorstep, and I called them to come get it three times over two months before I took it back myself. By the time I got home, their truck is in my driveway trying to drop that same damn package on my doorstep again!

      • Re: (Score:3, Funny)

        by canuck57 ( 662392 )

        while FedEx is traversing through worm holes

        Oh great! So FedEx will now tell me that my package was delivered. The bad news: it was delivered to me in an alternate reality. With my signature to prove it no doubt. Never mind the fact that "I" didn't get the damn package.

        No, it will deliver the package back in the future. Why does everything have to be Trek?

        • by st1d ( 218383 ) on Saturday June 28, 2008 @02:42PM (#23984111) Homepage

          Yes, walk outside tomorrow, and get a crapload of packages from yourself from the future, with a note "store these for me, k?" Maybe some UPS discount if they can deliver the package "anytime", cutting down on the number of stops they have to make. You know, saving money and all. Meanwhile, you're getting all these random packages for yourself 20 years from now.

          • by kesuki ( 321456 )

            and then the kids will all start saying 'that's so next week' when they get 1,239 packages that they ordered over 56.4 years, and they come in a courtesy semi trailer, ordered by date of opening them!

            but what happens, when a scientist takes advantage of this service, and sends himself everything he patented over his 120 year life span ,courtesy of his life extension drugs he sent himself before he patented them, marketed them and became the first googlbillionaire for having every technology advance for the

        • No, it will deliver the package back in the future. Why does everything have to be Trek?


          I thought it Fedex would be forced to turn the package over to the frelling Peacekeepers and Chriton would have to go in with Moia to recover it. Shows to go what I know, doesn't it?

      • by aplusjimages ( 939458 ) on Saturday June 28, 2008 @03:09PM (#23984345) Journal
        How do you think your alternate reality self feels? Now he's stuck with the "Hungry Bitches" DVD you ordered.
  • by OzPeter ( 195038 ) on Saturday June 28, 2008 @12:44PM (#23982991)
    Yet a previous attempt blew up.

    You use this phrase Its the first of its kind. I do not think you know what it means.

    And yes .. welcome to /. etc etc

    • the first of its kind that hasn't exploded yet
      • Re: (Score:2, Insightful)

        by hvm2hvm ( 1208954 )
        Well thanks captain obvious. But if they meant that they should have said that. "The first of its kind"<>"The first of its kind that didn't blew up". Also, might I add that it didn't blew up because it hasn't been launched yet? And yeah, it could have meant that its the first kind (like in model) of its kind or something like that. Yeah, this is slashdot so I'm kinda used to that.
        • Yet a previous attempt blew up.
          You use this phrase Its the first of its kind. I do not think you know what it means.
          And yes .. welcome to /. etc etc

          When writing a slashdot post, I try to be succinct.
          I figure those (few) who rtfas will sort it out.
          It would be the first solar sail successfully deployed. The planetary society one did not blow up; the rocket that would have deployed it blew up, so it never launched.
          I'm using these terms somewhat arbitrarily, what would expect from an aardvark?
          I'm new here: arbi

        • by rbanffy ( 584143 )

          "The first of its kind that hasn't failed already"

  • Bajoran-One (ST:DS9 reference).

  • Interesting (Score:2, Interesting)

    I hope my grandkids can one day go outside to take a spin around Mars with their solar sails.
    Still, the idea of a science-fiction object being realized in the real world is mighty interesting.
    Maybe tomorrow they will think about warp drives.
    • Still, the idea of a science-fiction object being realized in the real world is mighty interesting.

      Actually, the idea was first proposed by Johannes Kepler in the 17th century. And there are still a lot of basic misconceptions about solar sails and light sails, no doubt because of the word "sail".

      Simply put, they don't derive their thrust from the solar wind, the stream of charged particles emitted by the sun, but from the radiation pressure of sunlight (as stated in the summary), which provides vastly grea

  • by DerMatsi ( 1142757 ) on Saturday June 28, 2008 @01:16PM (#23983307)
    From TFA: "And like a marine sail, a solar sail could also bring you home. You could use the solar sail to tack your vessel, making it travel "against the wind," back to Earth." I don't see how this would be possible.. sailboats can do this because of a keel which exerts force on the water, which cannot be done in the near vacuum of space. Or am i missing something?
    • by amorsen ( 7485 ) <benny+slashdot@amorsen.dk> on Saturday June 28, 2008 @01:29PM (#23983423)

      Or am i missing something?

      Gravity.

      Disclaimer: Won't work if you accelerate beyond escape velocity.

      • by bcrowell ( 177657 ) on Saturday June 28, 2008 @02:17PM (#23983889) Homepage

        Gravity.

        No, that's incorrect. In space travel, the vehicle is in some orbit, and in the absence of a force other than gravity, it's just going to continue in that (typically elliptical) orbit forever. Say you're going to Mars, for instance. You needed to match orbits with Mars, which means you're in the same nearly circualr orbit around the sun that Mars is in. (Of course you also have to insert yourself into orbit around Mars, and get yourself out of that orbit as well, but let's not worry about that for now.) Once you're ready to leave, you don't just wait for the sun's gravity to pull you downhill back to Earth. You're in a circular orbit whose radius is greater than that of the Earth's orbit, so you're not coming back toward the sun unless you can reduce your velocity.

        To understand how you'd really use a solar sail, let's start with the case where you just want to increase your distance from the sun. Intuitively, you'd think that you'd just orient the sail perpendicular to the sun's rays, and let it thrust you outward. However, that doesn't work, because the thrust from the sunlight is orders of magnitude less than the sun's gravitational force. Doing that would be sort of like dialing down the strength of the sun's gravity by some tiny percentage, which would alter your orbit for a given velocity vector, but only by a tiny amount.

        What you actually do is to point your sail at an angle. The sunlight's thrust then has both a radial component and a tangential component. The tangential component does mechanical work [lightandmatter.com], because it operates in the same direction as the motion of the vehicle. That means it increases the vehicle's kinetic energy. The higher-energy orbit takes you farther out away from the sun.

        When you want to come back, you do something similar, but you tilt the sail the opposite way. The tangential component is now in the opposite direction compared to your motion, so it does negative work, reducing your kinetic energy.

        This web page [lightandmatter.com] has an example that calculates the optimal angle to tilt the sail at.

        • So the sailing analogy breaks down pretty fast. Too bad we can't just stick some kind of fin into the aether.

          • by kesuki ( 321456 )

            and mount lasers on it. you forgot the lasers, that was a shark fin right, you didn't specify!

    • Yeah I thought that was a bit odd as well. A keel gives a boat directional stability, not just sailing against the wind, but in every direction except straight downwind. You could put a sail on flat bottomed raft and the only direction you could move under sail power would be directly with the wind. Lacking a space keel would seem to limit any solar sail to going directly away from the sun. It could still be useful to any space craft, but only as a secondary system. If this works I'd like to see one in the
    • Yeah, I have brought up that same point in previous articles. What amazed me is that ppl would point out hoby cats but ignore the fact that the pontoon is designed to act as a sideboard. All in all, I think that you can broad reach if the sail force is smaller than the gravity pull, but I do not think that a beat is possible. Obviously, this is very useful for a run, or for slowing down.
      • Learned to sail in a HobieCat. They have daggerboards that can be dropped but, in truth, they're not all that good at sailing close to the wind.

        They can be tricky to tack, too--you have to make great, wide turns or do what's called wear, when you make a sort of loop at each tack in order to keep the wind astern. If you make the same sort of quick turn you would make in a monohulled boat, you might find yourself dead in the water.

        • by techno-vampire ( 666512 ) on Saturday June 28, 2008 @05:30PM (#23985503) Homepage
          AIUI, wearing and tacking are two separate ways to change course across the wind. In tacking, you turn your ship across the wind, using the ship's momentum to keep you going until your sails can catch the wind. (If you fail, your ship is said to be "in irons," pointing directly into the wind with no forward motion.) Wearing ship is much easier but, as you note, takes more room. You turn away from the wind going all the way around in a big turn and emd up with the wind on the other side of your ship. Although it's slower, it does have the advantage of avoiding any chance of getting stuck.
        • Yeah, I grew up racing melges c-scows. They have side boards. I have sailed a couple of cats as well, but they were 20-25' and all had dagger boards.
          As to the hobies, take a look at the smaller older ones. They had no dagger boards. Their outer edge was straight down and the inner edge curve to meet it. Think of the bottom of the "d". It worked well for them.
    • Re: (Score:3, Informative)

      by Phanatic1a ( 413374 )


      Tilt the sail. In one direction, it will increase your tangential velocity, and raise your orbit. In another direction, it will decrease your tangential velocity, and lower your orbit.

      • I think you're the closest so far. In any system where you're you're depending on the incidence and reflection of particles for thrust, be they photons, ions or whoknowswhatsitrons, you can change the thrust vector by changing the direction of the plane of reflection. If you like, you can have multiple reflective surfaces and direct the reflection pretty much wherever you like. You'll end up with thrust in any direction you want, as long as the amount of energy impacting and reflecting is asymmetrical.
  • Rail Sail (Score:5, Interesting)

    by Doc Ruby ( 173196 ) on Saturday June 28, 2008 @01:34PM (#23983469) Homepage Journal

    I'd like to see a maglev train on an Andean mountain firing a ship into Earth orbit, which then deploys solar sails to catch the much more plentiful direct solar radiation to accelerate it away from the Earth. That seems like a better way to use the infrastructure we have on Earth, where at least 25-30% of the solar power is lost in the atmosphere and the air creates drag on the accelerated ship, and to use the microgravity and vacuum of space where it's easier to deploy light, flimsy solar collectors in the full sunlight.

    • Go to the moon. I have never been that big of a fan of going to the moon until japan showed that there is a lot of uranium up there. That makes it very different. That gives us power to build and launch nuke ships. Combine these with sails that can use a laser from the moon. Not a bad way to get high speeds.
      • by kesuki ( 321456 )

        "until japan showed that there is a lot of uranium up there. That makes it very different. That gives us power to build and launch Giant Robotic mecha"

        fixed that for you, there is also a lot of titanium, to make the giant robots out of.

    • by njh ( 24312 )

      How about one of these:
      http://en.wikipedia.org/wiki/Launch_loop [wikipedia.org]

      It seems plausible. Especially if you look at using Al or CU loops in dyneema as diamagnets rather than iron as a ferromagnet.

  • by imipak ( 254310 ) on Saturday June 28, 2008 @01:46PM (#23983603) Journal
    Still time to chip in your contribution towards the Planetary Society's second attempt [slashdot.org] to do a working solar sail.
  • by CBob ( 722532 )

    Yep, we'd best start working on the boost lasers, they'd be handy for the 1st Kzin war too.

  • The Physorg article notes: "And like a marine sail, a solar sail could also bring you home. You could use the solar sail to tack your vessel, making it travel "against the wind," back to Earth." But, I thought that do sail across the wind you need something to provide "lift" to counter the lateral force of the sail, which is provided in boats by a keel, or centerboard, or daggerboard, or a fin and rail on a windsurfer, or a skeg, etc. etc. Where's the counterforce in a solar sail in space?
  • 30-56-99 are correct. Limited 4 and 8 are missing.

    And now you'll have two renegade programs running all over the system in a stolen simulation.

    End of line.

  • Sure. Next article (Score:4, Insightful)

    by heroine ( 1220 ) on Saturday June 28, 2008 @05:37PM (#23985537) Homepage

    > It will travel to space onboard a SpaceX Falcon 1 rocket

    Good luck with that one. They can't even get any time on the island because they have to beg & steal for government launch facilities.

    A bit disappointing that the space station isn't being used for breathrough research like this. Instead it's busy enough keeping itself alive & selling Buzz lightyear promos.

    • They must be doing something right, cause apparently, the rocket is on the pad right now going through dress rehearsals.

      clickenzie here. [spacex.com]

  • On the cruise you will have peace of mind with a garden reeked of love.
    For the sake of earnest unity on this voyage to infinity.
    On the voyage to infinity, can't forget to take your soul.
    Cause at the port you'll find no double sign.

  • "They are well known to science fiction readers, otherwise not so much."

    They are well known to those familiar with space history. We learned how to build these sails from Echo 1A and Echo 2, launched back in the 60s. Both were aluminized mylar balloons, used as passive microwave reflecting communications satellites. Both were "blown" off orbit by solar pressure. Analysis of the orbital data told us the why and the how much, so now we can do it accurately.

    As for "a previous attempt blew up", the same thing h

Bringing computers into the home won't change either one, but may revitalize the corner saloon.

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