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Space Science

Space Sails Could Bring Used Rockets Back To Earth 76

GordonCopestake writes "An article from New Scientist proposes that all new spacecraft have sails attached to bring them back to earth — a measure that would reduce the amount of garbage in space. From the article: 'The risk to spacecraft from a collision with space debris could be reduced by equipping launchers with a gossamer-thin "sail." The idea is to deploy the sail after the rocket has released its payload to amplify the drag of the last vestiges of the atmosphere, and so force the rocket out of orbit.'" Wired has a related story about the risks faced by the space shuttles as they share orbits with tons of drifting space debris. "... in the 54 missions from STS-50 through STS-114, space junk and meteoroids hit shuttle windows 1,634 times necessitating 92 window replacements. In addition, the shuttle's radiator was hit 317 times, actually causing holes in the radiator's facesheet 53 times."
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Space Sails Could Bring Used Rockets Back To Earth

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  • Choke (Score:1, Funny)

    by Anonymous Coward
    We should not stop producing CO2. We are gonna need the heat when all the space junk blocks the sun. Why do humans have a need to choke on their own waste? Are we really a bacteria or something?
  • And the old junk? (Score:5, Interesting)

    by JorDan Clock ( 664877 ) <jordanclock@gmail.com> on Saturday April 18, 2009 @12:17AM (#27623597)
    This might be helpful for rockets launched in 4 or 5 years (Which I think is a very generous estimate on how long something like this would take to be adopted even close to universally.) it doesn't address the issue of all the stuff already up there. How long will the majority of the debris in orbit remain? How effective are these sails when they themselves are punctured by debris? It's a great plan for keeping things from getting worse, but as I understand, a lot of things up there that are in danger of causing damage will be up for quite some time.
    • by WindBourne ( 631190 ) on Saturday April 18, 2009 @12:22AM (#27623631) Journal
      this might be where Private Enterprise wants to step forward and work on getting a space ship to approach a used up sat, and attack a sail to it to force it down the gravity well. With small control units on the sail, this could be really useful. That same tech would be needed for remote servicing of sats anyway, if private enterprise wants to take that on. As to who would pay, well, I would guess that whoever owns the sat would find it cheaper to pay 5-10 million to de-orbit a sat than deal with lawsuits. For the small to medium size, well that will require a totally different approach.
    • Re:And the old junk? (Score:5, Informative)

      by Profane MuthaFucka ( 574406 ) <busheatskok@gmail.com> on Saturday April 18, 2009 @12:25AM (#27623655) Homepage Journal

      The debris in low orbits where the Shuttle operates will return within just a few years. Higher than that means it stays up longer.

      If an object is orbiting twice as high as the shuttle, about 500 miles, it'll stay up roughly a couple centuries. Just a bit higher than that and you're measuring orbital lifetimes in millennia.

      • Re: (Score:3, Informative)

        by bit01 ( 644603 )

        The debris in low orbits where the Shuttle operates will return within just a few years. Higher than that means it stays up longer.

        Do you know how much of a difference the size of the debris makes? The wikipedia orbital debris entry [wikipedia.org] doesn't say.


        Don't be a programmer-bureaucrat; someone who substitutes marketing buzzwords and software bloat for verifiable improvements.

        • Re:And the old junk? (Score:5, Informative)

          by rcw-home ( 122017 ) on Saturday April 18, 2009 @02:01AM (#27624069)

          Do you know how much of a difference the size of the debris makes?

          Densities of materials vary widely, but as a rule of thumb, mass increases with the cube of an object's size, but drag only increases with the square.

        • Re: (Score:3, Interesting)

          by Hurricane78 ( 562437 )

          I found the notion pretty impressive, that a piece of shrapnel, only 1 g in weight, is like a 600 kg (~1323 pounds) bike, crashing at them with 600 km/h (~373 mph). Imagine that, with the size of a pencil tip, hitting a window. Now imagine a piece of half a ton doing the same...

      • Re: (Score:3, Informative)

        It depends tremendously on the orbit and the object. Some 'objects', like dumped urine or water, submlimate. They're still deadly if they hit you from even a slightly different orbit, since we're talking about base speeds of roughly 18,000 mph in low earth orbit: it's the difference between the orbits that determines their relative velocity, and that's easily as much as 10%. (Head-on collisions are basically unheard of: one object would have to be orbiting the other way entirely, and no one does that due to

        • (Head-on collisions are basically unheard of: one object would have to be orbiting the other way entirely, and no one does that due to the launch costs of orbiting against the Earth's spin.)

          Qualifier: polar orbits allow this geometry of impact.

          • You're quite correct: I neglected that polar orbits, if launchers don't pay a bit of attention to existing orbits, could easily create such cases.
    • Mass Catcher (Score:3, Insightful)

      by StCredZero ( 169093 )

      I wonder if we could operate a remote-controlled Mass Catcher [nasa.gov]? The one designed for the 1975 Stanford Summer Study would do if you left off the intake grid of cables. It would be a rotating Kevlar cone. Centrifugal force would hold loose regolith in place, which would act to absorb the impact of the intercepted debris. The same rotation would also act as artificial gravity to prevent the escape of secondary splash debris. Using a pellet launcher as a thruster would be safe, since the pellets would be t

    • Re: (Score:3, Interesting)

      by roystgnr ( 4015 )

      How effective are these sails when they themselves are punctured by debris?

      99.999% as effective. At orbital altitudes air doesn't behave like a continuum, just like independent molecules bouncing around. This is bad if you're trying to design a wing (pressure doesn't affect flow in the same way and your lift to drag ratios suck) but great if you're designing a parachute (a small hole will let molecules through at the site of the hole, but won't affect their absorption/reemission or their reflection elsewh

  • When we've got countries blowing up satellites in orbit, that's far worse than a big booster plodding along in a decaying orbit.
    • Any ban that is worth their salts would have a description wanted, a means to verify, and a means to punish those that break that. BUT, that is impossible to do. Take the case of North Korea. Clinton got NK to agree to not do Nukes. It was absolutely prohibited from doing so. Ok. BUT W came into office and started calling NK names. Instantly, it is found that NK has been doing all the steps that are useful for civilian as well as military while pure civilian steps are missing. IOW, they met the letter of th
      • Re: (Score:1, Flamebait)

        by Gothmolly ( 148874 )

        The solution is obvious - nuke the Chinks.

      • You make the assumption that North Korea started mixing household chemicals in their backyard and instantly created their nukes. They had LOTS of help from other countries. The point of a world-wide ban is that you shut down these kinds of conduits. How do you know that China is secretly building nuclear subs BTW? Countries have ways of verifying through espionage.

        If there's a space weapons ban, there's practically no way to test without the whole world coming down on you. Your analogies aren't the sa

        • How do you know that China is secretly building nuclear subs BTW? Countries have ways of verifying through espionage.
          And that is why China is paranoid about the outside world with our aircrafts and boats. We are working hard to spy and to know EXACTLY what their count is, while China is doing their utmost to keep it hidden. 1935 Germany was the same way. In fact, all countries that are gearing up for a war will be that way. Back in the 50's and 60's, America and USSR KNEW that each other were spying on th
  • Woah (Score:4, Interesting)

    by Idiomatick ( 976696 ) on Saturday April 18, 2009 @12:19AM (#27623613)
    Those numbers are frigging huge compared to what I thought. 300 measurable hits per mission is crazy. And it will only get worse. I don't think sails are the solution. We need a way to clean it up. (While i liked PlanetES I don't think doing it by hand is very viable)
    • Re: (Score:3, Informative)

      by Anonymous Coward
      The 317 hits were over 54 missions. ~6 hits per mission.
      • That is JUST the radiator... so windows and radiators ~36 hits per mission. Which is insanely high. These things are impacting at kilometers/second. I don't know why I thought it was 300 earlier.... I think this explains my Linear Algebra exam though :(
  • The universe is mocking us for not thinking ahead. Again.

    And our reaction? "Let's make those pieces bigger!"

    • by NotQuiteReal ( 608241 ) on Saturday April 18, 2009 @01:36AM (#27623997) Journal
      The universe is mocking us for not thinking ahead. Again.

      Don't anthropomorphise the universe. It doesn't like it. All kidding aside, I am not sure that you said anything. Do you only want to put small things into orbit? Or are you saying we should make sure "what goes up, must come down?"

      I think you are saying adding the sails would make the debris bigger, and thus even more of a problem.

      Maybe you should have just said "the road to hell is paved with good intentions" and left it at that.
    • We do need "bigger pieces", we don't want that layer to be too fluid when we start building on it.
    • Re: (Score:2, Informative)

      by ring-eldest ( 866342 )

      We are the tubgirl of Sol system.

  • Shoot em up? (Score:3, Informative)

    by powerslave12r ( 1389937 ) on Saturday April 18, 2009 @12:23AM (#27623641)
    Well, with the kind of weapons tech being developed (electric eye with lasers?), it shouldn't be a big deal burning down these debris. The problem would be allowing (or acknowledging that *anyone* has) that kinda weaponry up there.
    • Re: (Score:3, Informative)

      by davolfman ( 1245316 )
      Yeah, no. We don't have anywhere near the weapons tech needed to actually vaporize orbiting objects, it would just take too much power. All we can do is push them out of orbit, or scatter them into even more orbits as shrapnel.
    • Bad idea (Score:5, Insightful)

      by bigsteve@dstc ( 140392 ) on Saturday April 18, 2009 @01:26AM (#27623941)
      If you blow up an old booster ... or satellite ... you only make the space junk problem worse. Instead of 1 large lump of junk that is easy to track and (with luck) avoid, you end up with thousands of smaller lumps, each of which would damage or destroy a satellite.
      • Thousands of smaller lumps would have a massively larger surface area, so wouldn't they fall a lot faster? So within a year or so they'd be gone, no?

        • by khallow ( 566160 )
          Depends how high the orbit is. The problem is that the orbits that have orbital debris problems also are high enough that it'd take a lot longer than a couple of years for small pieces of orbital debris to deorbit.
      • Issue licenses to commercial space flight providers. Their spacecraft would be fitted with big-ass laser canons. Rich folks would fork out a few million for the privilege of bagging some space debris.

        Each flight would have "Space Hunting Guides & Skinners," grizzled, experienced former government astronauts. The skinner would ensure that there was no smaller junk left over after the kill. It would be burned up in the nightly campfire with a yet-to-be-determined technology.

        The guide would say cool

  • Instead of sending it back to earth, why not just keep it out there, but collect it all to one central location? We paid once already to launch it out there, and we know we want increase our space presence, so why not have a junkyard where you can go get stuff to recycle? Or, crash it into the moon and build your moon base near it, then you can keep adding to and utilizing it.
    • by Rakishi ( 759894 ) on Saturday April 18, 2009 @01:11AM (#27623867)

      Space is not earth.

      Moving things in space and keeping them from crashing into the atmosphere requires energy. Energy means fuel and fuel means you need to pay to send it up. Docking objects in space requires complex electronics which means even more mass to send up.

      Recycling requires a highly advanced and complex industrial base which doesn't exist in space. If it did then you wouldn't need the junk since you can mine your own raw materials.

  • by r00t ( 33219 )

    You're going to get a hole in your radiator.

    You're going to get hit in the window 30 times.

    Two windows will need to be replaced.

  • Hit or Miss or Hit (Score:5, Insightful)

    by DynaSoar ( 714234 ) on Saturday April 18, 2009 @01:09AM (#27623857) Journal

    "For the final stage of an Ariane 5 launcher, the conical sail would need to have an area of about 350 square metres and be supported by an inflatable mast 12 metres long."

    And the expected time to reentry is 25 years.

    Good luck on keeping something inflated in space for 25 years. And that's not even considering the probability that the the mast, and the much higher probability that the large sail, will be hit by orbiting debris during that time and torn to shreds

  • Making solar sails (Score:4, Interesting)

    by Kim0 ( 106623 ) on Saturday April 18, 2009 @01:34AM (#27623985)

    Here is my idea for making an extra light solar sail:

    http://kim.oyhus.no/Solar_sail.html [oyhus.no]


  • by BikeHelmet ( 1437881 ) on Saturday April 18, 2009 @02:50AM (#27624255) Journal

    It's rather like taking a stroll down Main St. in one of those western cowboy movies.

    Anyone know how powerful a big electro magnet would have to be to suck debris within say... a mile, towards it?

  • You could vent water vapor in the path of denser groupings of debris. This would allow you to sap kinetic energy from clouds of debris without incredibly fancy or expensive lasers. Still, getting large volumes of water up into space is itself a costly endeavor and might only be cost effective in bringing down denser debris clouds or groupings. Add that to the fact that water vapor will disperse and descend rather quickly and this might only be viable as a way to clean up right after a debris creating eve
  • by rts008 ( 812749 ) on Saturday April 18, 2009 @04:03AM (#27624563) Journal

    Space sails? That's so low tech.

    It's obvious we need deflector dishes and shields.

    Star Trek has taught us that much!

  • The problem with space travel won't be the engines or how to recycle the used food, it'll be all the rocks constantly beating on the hull.

    • Which is why bigelow's BA-330 is interesting. About a foot of material as well as sealing that ABSORBS the item, rather than trying to reflect it. For distance travel, do the smart thing and put that in a metal can.
  • Such a Waste (Score:4, Interesting)

    by 32771 ( 906153 ) on Saturday April 18, 2009 @07:42AM (#27625521) Journal

    I think that any mass in orbit is far more valuable there than back on earth. It still has all the energy the owner has paid for by launching it in the first place, and at ~$1000 per kg in LEO that is nothing to sneeze at. I think the solar sails should be used to cart the stuff into a higher orbit where the parts can be stored with less effort.

    The problem is that whatever we sent up is not built for reusability it would seem. Without a decent plan to produce something from space junk I guess nobody is going to worry about where the hardware in orbit goes beyond its eol, it has paid for the launch costs already why worry about much costlier manufacturing in orbit. Then it is also safer to just drop the stuff. This proposal is more of the same shortsighted thinking however. We will continuously put stuff into orbit, why let it decay back to earth if there could be a continuous reuse of material in orbit? Something goes up nothing comes down!

    The space junk problem could finally lead to better planning for the future. Somebody could come up with an in orbit manufacturing and launch facility which buys the energy + material value of your satellite/booster. Its main bussiness would be in orbit manfacturing and launch of hardware with a certain orbit.

    I would venture a guess and say that we already have the technology to make this work today. So it is time to check whether this could become a viable business model.

    • Re: (Score:3, Interesting)

      by khallow ( 566160 )
      And as long as that material is uncontrolled, it easily can destroy anything else that has been launched for $5,000 or more per kg.

      PS, your cost is incorrect, especially if we're just talking energy. It takes only somewhere on the order of $10-20 per kg in energy to put something in orbit. The cost of objects in orbit isn't due to the energy of the objects. Currently, the Russians are the cheapest. And they might go down to $3,000-4,000 per kg to put things in orbit.

      And what will a space salvage busin
      • by 32771 ( 906153 )

        I made a silly mistake about calculating the cost to orbit, it had something to do with converting between pounds and kilograms. I assumed $2000/pound through a russian launch (my source: www.futron.com/pdf/resource_center/white_papers/FutronLaunchCostWP.pdf).

        I agree with you that looking only at the energy would be too narrow a focus. Launch costs include ground operations and other things whereas the launcher itself isn't even the biggest part of the costs.

        One could use different technologies once in orb

        • by khallow ( 566160 )
          As I understand it, launch costs usually don't make up a large portion of the overall costs of a space mission, but they are the decisive factor. The problem is that launch costs are the ante, the minimum amount that a mission will cost even if everything else is free. For example, if you have a satellite that weighs 1 tons, it'll cost $5 million or more to put up. If your desired return on investment is 20% per year (reasonable for a high risk start up), then you need to make at least a million dollars a y
    • by Rakishi ( 759894 )

      I think that any mass in orbit is far more valuable there than back on earth. It still has all the energy the owner has paid for by launching it in the first place, and at ~$1000 per kg in LEO that is nothing to sneeze at.

      There's already plenty of mass in space, we can cart up rocks from the moon for a pittance if we wanted to. The problem is that all that mass is useless since the cost of manufacturing things in space would be insane.

      I think the solar sails should be used to cart the stuff into a higher orbit where the parts can be stored with less effort.

      They aren't putting solar sails on these things in case you haven't realized.

      So you want to spend mass to send up complex (and fragile likely) solar sails with complex guidance systems? Solar sails which, asfaik, have never been shown to actually work yet and that are not used by any existing s

  • Pointy sticks to spear the space trash.
  • by advocate_one ( 662832 ) on Saturday April 18, 2009 @07:57AM (#27625607)
    use the sails to move them into higher designated parking orbits so the materials can later be used up there when we need to start assembling craft in space... it costs an enormous amount to put mass up there, why waste the energy invested?
    • by MobyDisk ( 75490 )

      Are you planning to build a space station from flecks of paint, foam, and metal? Unlike in cartoons [slashdot.org], you can't just build anything from random metal parts.

      • we're talking about booster stages and satellites here, not fragments, that's another problem... if the spent booster stages and defunct satellites can be moved up to a parking orbit using solar sails, then there'll be a much smaller debris problem in the main orbits as these defunct parts won't be colliding with each other in the prime orbits.
    • by Rakishi ( 759894 )

      First of all because atmospheric drag slows things down and robs them of energy. Going to a higher orbit requires increasing velocity and adding energy. In other words, the laws of physics prevent your scheme from working.

      There are other reasons I can think of but I think this one is enough.

  • And it involves sending a lot of baseball players to space, with steady supplies of baseball bats.

  • Why not take this further. Shoot up rockets with big sails attached for the sole purpose of collecting space debris. put them in an orbit then deploy their sails or parachutes so they will catch a swath of debris. if the rocket is traveling slightly faster than the debris the sail wont be punctured and it will fill up before losing its velocity and then falling out of orbit.

  • http://www.tethers.com/TT.html [tethers.com]

    I saw Robert L Forward talk about this at a con years ago.

  • Instead of atmospheric drag a conductive tether moving through the Earth's magnetic current generates a current and radiates the heat from tether resistance. The dissipated energy will eventually bring the satellite down. The technique has been developed by Tethers Unlimited and the late Dr. Robert Forward [wikipedia.org]

    http://www.tethers.com/TT.html [tethers.com]

Basic is a high level languish. APL is a high level anguish.