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Japan Successfully Deploys First Solar Sail In Space 284

Posted by timothy
from the beginner's-luck dept.
An anonymous reader writes "This morning the Japanese space agency, JAXA, successfully unfurled a solar sail in space for the first time. Solar sails offer the best hope for deep space exploration because they eliminate the need to carry fuel. The Japanese spacecraft IKAROS created centripetal force by spinning, allowing it to launch the 0.0003-inch-thick sail. While deployment is a challenge in a zero-gravity environment, spacecraft — unlike airplanes — don't have to contend with drag, so with each photon that hits the sail helps the spacecraft gather speed."
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Japan Successfully Deploys First Solar Sail In Space

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  • by 54mc (897170) <samuelmcraven@g[ ]l.com ['mai' in gap]> on Thursday June 10, 2010 @06:18PM (#32529162)
    I thought those crazy japanese were angels, but much to my surprise, they climbed aboard their starship and headed for the skies.
  • by History's Coming To (1059484) on Thursday June 10, 2010 @06:21PM (#32529202) Journal
    Jetpacks? No. Flying cars? No. Sentient robots? No.

    Solar sailing? Oh yes! I love this, it's one of the signals that we're living in the future, if you grew up on Clarke, Asimov et al. Required reading: Clarke's "A Wind From The Sun", Stross's "Accelerando".
  • Focus (Score:5, Insightful)

    by AnonymousClown (1788472) on Thursday June 10, 2010 @06:28PM (#32529284)
    Did anyone else have the thought that, here are the Japanese, designing and building spacecraft to further explore our Universe and progress mankind's knowledge.

    Here are we, the US, once the leaders of space exploration, have spent billions of dollars to go back and relive some glory (Moon shot) and canceled that, we have canceled the Shuttle program with no other vehicle to replace it, and in the process put a halt to much basic research.

    We're kind of like that pathetic ex High School jock that's trying to relive his glory days.

    • Re:Focus (Score:5, Funny)

      by Anonymous Coward on Thursday June 10, 2010 @06:33PM (#32529344)

      We're kind of like that pathetic ex High School jock that's trying to relive his glory days.

      But we threw 4 touchdowns in one game, man. IN ONE GAME!

    • Re:Focus (Score:5, Informative)

      by 0xdeadbeef (28836) on Thursday June 10, 2010 @06:36PM (#32529382) Homepage Journal

      Can you count [nasa.gov]?

      • Re: (Score:3, Insightful)

        by Charliemopps (1157495)
        I can count the number of non-scientists excited about those projects on 1 hand. Does that count? If NASA continues only to accept projects that do not interest the general public they are going to completely lose funding within a few decades.
        • Re: (Score:2, Insightful)

          by 0xdeadbeef (28836)

          No, you can't, because the highest you can go is 0x1F.

        • I can count the number of non-scientists excited about those projects on 1 hand. Does that count? If NASA continues only to accept projects that do not interest the general public they are going to completely lose funding within a few decades.

          Fine by me. That will just remove all the political ill-will that's been focused on holding back commercial space development.

      • Re:Focus (Score:5, Informative)

        by BJ_Covert_Action (1499847) on Thursday June 10, 2010 @07:01PM (#32529666) Homepage Journal
        Meh, don't bother. It's hard to convince the people who keep posting this kind of shit that the American space industry is anything but dead. Nevermind the fact that NASA still has the most impressive space research facility on the planet (JPL) or that they are working on various lifting technologies that include everything from hypersonics to extremely advanced aerodynamics (AMES research facility). Nevermind the fact that American business are now starting to launch vehicles into space, without existing government contracts, unlike almost any other nation on the planet. Nevermind the fact that Cassini has just detected evidence that methane based lifeforms may exist on Titan. Nevermind the fact that NASA is trying to land a rover the size of a mini cooper on mars.

        Nah, we can just forget all of the missions that NASA has currently studying the Sun, Mercury, Pluto, Saturn, and just about every other interesting object in our solar system because Obama killed the space industry, dontcha know?

        As old as it gets to see people post this kind of crap all over the internet, there is absolutely nothing that will convince them that America, space industry included, is nothing more than a washed up has been that is wallowing in its own filth these days. It's like trying to talk reasonably to a kid who has his fingers in his ears and is shouting, "La la la la la I can't hear you!" They'll only learn otherwise when they make the conscious decision to remove those fingers and grow up.
        • Re:Focus (Score:5, Insightful)

          by Sycraft-fu (314770) on Thursday June 10, 2010 @07:37PM (#32530086)

          Certainly does seem that way. There just seems to be a subculture of Americans, of which Slashdot has more than normal, that love to hate on America. Whatever America does, it's bad. They see the nation in a continually bad light. The flipside of that is usually that they look at other nations with rose coloured glasses. They see only the good, they don't see any down side. The fail to see that there are problems with any nation, as nations are made up of people and we are all flawed.

          For some I think it is just because the see that America may be sliding from a position of dominance and they take that to a nihilist extreme where it means America will become nothing, a 3rd world hellhole or worse. For some reason it never occurs to them that there have been other places like, say, England, or France that once were superpowers and now are just very nice places to live.

          Whatever the case, it does get rather annoying. Criticizing the problems America has is healthy, and necessary. Only though looking at the faults and trying to correct them can you get better. Just hating on America all the time is stupid and unproductive.

          • Re: (Score:2, Troll)

            by abigor (540274)

            It's not just the US - it seems there are people in every modern western society who hate their country/the west in general. They think that "we" owe the rest of the world for all eternity, even if it means our own destruction. Stupid and unproductive, like you said. I experience it on a regular basis from hand-wringing self-loathers.

          • Re: (Score:2, Insightful)

            by ZirconCode (1477363)

            There just seems to be a subculture of Americans, of which Slashdot has more than normal, that love to hate on America.

            Do you want to know why so many people hate Americans? It's because Americans are so full of themselves that they can't imagine a non-American English speaker.

            • by Trepidity (597)

              The poster in question explicitly identified himself as an American, using the phrase, "we, the US". It has nothing to do with assuming all English speakers must be American. It is reasonable, I think, to assume that people who use the pronoun "we" to speak about the United States are Americans.

            • Re:Focus (Score:5, Insightful)

              by argStyopa (232550) on Friday June 11, 2010 @06:49AM (#32533412) Journal

              I found your statement to be amusingly ironic. Only on /. would it be rated 'insightful'.

              First, please understand that Americans are generally staggeringly provincial; most Americans don't (and never will) own a passport. Most will never leave the US, because they don't have to. Most do not speak a foreign language. Contrary to the view of 'world citizens' like many Euros (as well as a significant number of patronizing, elitist Americans), this isn't because the bulk of Americans are stupid hicks, they simply don't need these things. Everything they can do, need to do, and want to do, all can take place within the comfortably-broad confines of US borders. If they're feeling slightly adventurous, they can go to Canada (barely another country) or even Mexico (where most vacation destinations are less hispanic than Laredo, TX anyway).

              So to your point, regarding Americans' 'inability to imagine a non-American English speaker', of course they don't generally assume that, it wouldn't make any sense for them to do so in context.

              Secondly, what other countries seem to interpret as arrogance appears to be some sort of reverse projected narcissism: "OMG you are so self-centered, you never notice me!"...and if you don't get the irony in that statement, well, then you're hopelessly humorless.

              To suggest that lack of regard equals arrogance is naive, presumptuous, and ultimately self-defeating. To then use THAT as a motivation to generically HATE someone, based on nothing more than their country of origin? I'd call that a self-justifying conceit - dare I call it arrogance? - itself.

              Get over yourself - nobody automagically is entitled to that level of importance; not Americans individually, and certainly not you.

        • Re: (Score:2, Informative)

          by revjd909 (749913)
          The part that's most frustrating is "What's the size of the NASA budget?" And how does that compare to the size of our military budget? We could have a colony in space or on the moon by now, if we weren't spending close to $1 trillion/year making war. Here's a little look at more of what Japan's planning: http://pinktentacle.com/2010/06/futuristic-mega-projects-by-shimizu/ [pinktentacle.com]
          • by oatworm (969674)
            Correct - instead of spending $1 trillion/year making war, we could instead spend an additional $1 trillion/year on various entitlements like Europe. Whether that's a good thing or a bad thing depends on your point of view, of course; many people would rather just keep the $1 trillion in their pockets and not redistribute it all over the place.

            The reason we're (by "we", I mean everyone, not just the US) not spending a bunch of money on sending people to space is because, outside of a few die-hards on Sla
        • by astar (203020)

          Precise is good. US manned space exploration is dead. Indeed, there s reasonable evidence that OMB is in charge of NASA. From there, it is reasonable to wonder about the future of unmanned space exploration by the US.

          On the other hand, what do I know? Perhaps you can point to concrete officially announced plans for a manned misson even to a lagrange point?

          And if everything is all so sensible and rosy, it is odd that there is substantial concern that Obama et al is violating the law with his cutbacks. S

        • I think the point is that we're holding NASA and the US space program to a different standard. It's been 40 years since we first landed on the moon. Sure, there have been tons of other things since then, rovers and faint traces of molecules possibly-maybe connected with life, but people want something that can top that. People want something as significant and monumental and inspirational as putting humans on another body. And we're just not getting it. I'm not saying the US is a has-been, just an unde

      • by c++0xFF (1758032)

        I hadn't thought about it before, but Pioneer and Voyager are still on that list. Considering the science that's still being done by Voyager (mild, but still ground-breaking), I think it's more than appropriate.

        Maybe one day we'll contact Pioneer 11 again.

    • by copponex (13876)

      No, we're an ex jock with a coke problem they are still in denial about. We're wondering why we're always broke, when the answer is under our proverbial noses. [youtube.com]

    • We're kind of like that pathetic ex High School jock that's trying to relive his glory days.

      Absolutely not. If only the US tried to revive the old glory! Instead, it's more akin to a guy watching TV all day and drinking beer, overweight, lacking curiosity, enthusiasm, courage. His greatest ambition is watching the Super Bowl.

      The USA could not get back to the Moon even if she wanted to - the knowledge is lost, gone. There is no past glory, because the Apollo program could not be re-created today, without a massive investment in research. The Apollo program is not past glory, it's lost glory, and do

      • by Nyeerrmm (940927)

        Of course we could go back to the moon in 5-10 years if we wanted to -- we just need the budget. Constellation (which I believe should be shut down) was perfectly capable of getting back there, if only it were funded properly.

        The research we need is in ways to do it better and cheaper, because Apollo-level funding was an apparition of the cold war and was unsustainable. Things like propellant depots, electric propulsion, radiation shields, and long term life support are what we need.

        Going back to the anal

    • by Sycraft-fu (314770) on Thursday June 10, 2010 @06:54PM (#32529594)

      I mean they most certainly didn't recently deploy two rovers to Mars that WILDLY exceeded expectations. They didn't then also deploy another, fixed, lander which while not as wildly successful exceeded it's planned mission significantly. Nope, none of that happened...

      Oh wait, yes it did.

      Please, while the US space program is not without troubles, it isn't as though it is at a standstill. NASA continues to do some amazing work, and much of it like the landers are pure science, to further our knowledge.

      Stop with the US hate that is so popular on Slashdot. The US is not perfect, no nations is, indeed no human endeavor is. There's plenty to criticize and that includes in the space program. However trying to pretend as though they accomplish nothing of note is silly. Two successful recent Mars missions shows that. No, they weren't manned, neither is this Japanese craft. Putting people in space is dangerous and often not worth the expense. We can learn a lot with remote operated equipment.

    • by geekoid (135745)

      "nd in the process put a halt to much basic research."

      False.

    • Re: (Score:2, Interesting)

      by sexconker (1179573)

      Seems to me that the US and Russia (and the Germans working on both sides) did all of the leg work in the field.

      Seems to me a satellite, however fancy, is orders of magnitude simpler than manned space travel.

      Seems to me Japan doesn't exactly a military to waste money on, on account of that whole World War II thing. Or two current wars. Or failed banking and auto industries. Or morans who bought houses they couldn't afford. Or...

      Seems to me the US is shying away from public space exploration, while the p

      • by oatworm (969674)
        Actually, Japan is still cleaning up the mess from when its banking sector collapsed in the early '90s; it's a big part of the reason that Japan's public debt is nearly 200% of GDP [wikipedia.org]. How did it collapse? Well, back in the late '80s, the Japanese were heavily speculating in... you guessed it... real estate [wikipedia.org].

        As Mark Twain once said, history doesn't repeat itself, but it does rhyme.
    • by grumpyman (849537)
      Sounds like Al Bundy :)
    • Sadly, I think that you might be about as bright as one.
      Yes, W did in fact cancel the shuttle program with none to replace it.
      But, will that put a halt to basic research? Not even close.
      Since we lost the columbia, it has been used ONLY for the ISS (and the hubble rescue). Since the start of the ISS, it is been dominantly used for the ISS (and from my perspective, that is all that it should have been used for; The ISS is a much better platform for science missions than the shuttle).

      Now, exactly what sc
    • by murdocj (543661)

      No, I wouldn't have that thought, because we in the USA have increased the space budget, cancelled the underfunded retread program to go to the moon, and have started focusing on the cool advanced space technologies that will propel humans to other planets.

    • Re: (Score:2, Insightful)

      by UK Boz (755972)
      Why does Japan's Success have to mean America's failure?
    • by steve_bryan (2671)

      With the confirmation that ice (water) is available in some craters near the moon's poles (and lots of it) much has changed. It could be possible to build self sufficient bases on the moon. I don' know what other activities might be pursued but it would be a great place for astronomical observatories away from signal pollution of the Earth (ok, actually mainly people) on the far side of the moon. Also there really is tritium in the moon's regolith. I don't know about the economic issues of sending it back t

    • by sunspot42 (455706)

      we have canceled the Shuttle program with no other vehicle to replace it, and in the process put a halt to much basic research.

      What basic research? The Shuttles have been diverting literally tens of billions of dollars a decade away from basic research since the 1970's. They've proven to be scientific and financial black holes. Pretty much the only thing we learned from the Shuttles is that the Shuttle didn't live up to any of the promises that were made while it was being developed and built. They prov

  • Which force? (Score:5, Insightful)

    by icebike (68054) on Thursday June 10, 2010 @06:31PM (#32529312)

    Centripetal or Centrifugal?

    Spinning creates what is commonly called Centrifugal force, and the tethers of the sails constitute what is generally referred to as the Centripetal force.

    About here is where some physicist jumps up and tells me everything I learned in the past is wrong and I should shut up and sit down.....

    • Re: (Score:3, Funny)

      by Fluffeh (1273756)

      About here is where some physicist jumps up and tells me everything I learned in the past is wrong and I should shut up and sit down.....

      Yes. Sit down and shut up. Also, because you didn't pay attention the first time you learned it, I won't waste time explaining it again.

      *smirk*

      *sips coffee*

    • by Anonymous Coward on Thursday June 10, 2010 @06:34PM (#32529358)

      Obligatory xkcd:

      http://xkcd.com/123/

    • Re: (Score:3, Informative)

      by pluther (647209)
      You are correct. Centripetal force is the force exerted by the tethers holding the sail to the spacecraft. (Force from the edge towards the middle).

      Centrifugal force is what pulls the sail out. (Force from the middle to the edge.)

      Also, there's no such thing as centrifugal force: as explained by, who else, xkcd [xkcd.com]

    • [Emily Litella]

      What is all this fuss I hear about centipedes being forced out? It's terrible! Centipedes have enough problems as it is!

      [/Emily Litella]

  • Commence Whining (Score:5, Insightful)

    by RobinEggs (1453925) on Thursday June 10, 2010 @06:33PM (#32529338)
    Commence whining about the death of the US Space program, the US falling behind other nations, and how it's all the (Pick one: Obama, Bush, Clinton, Bush Sr.) administration's fault in 3.....2......1....blastoff.

    Don't get me wrong, it's all basically true; it's just tiresome whining to listen to.
    • I blame Jack Thompson. If he had pushed just a LITTLE harder against violent video games, none of this would have happened.

      And don't ask how, I hate spelling out every little detail. Figure it out.

    • by pluther (647209)

      What killed the American space program was not any one administration (let's start with Nixon for that, and include every president since).

      It was the American people themselves, with their apathy, demand to be constantly amused, and lack of imagination.

      We've all heard it:
      "We went to the moon, there's nothing there!"
      "Why spend money in space when there are still problems on Earth that need solutions?!"

      That said, though, NASA, as defunded as they are, are still doing some pretty damn awesome things - just not

      • Re:Commence Whining (Score:4, Interesting)

        by Nyeerrmm (940927) on Thursday June 10, 2010 @07:44PM (#32530152)

        It's a common theme -- but I think its a little misguided. It occurs to me that part of the problem is that NASA thinks of Apollo-level funding as the rule rather than the exception.

        Done right, we could do quite a bit with the current Human Spaceflight (HSF) budget. Given that the post-Apollo budget levels are relatively consistent, it seems that current funding level is the politically sustainable level, without external influences (i.e. Cold Wars). If there had been no space race, I can't help but think that NASA would be much better at doing impressive things on the HSF side on their more modest budget.

        $17B is a pretty good chunk of change, and the fact that its been increased despite an across-the-board budget cut on other non-defense discretionary spending shows that there is some significant support for it. We (the space community) tend to think of 1% GDP as the "correct" amount that should be spent on space exploration. Maybe if we get used to the idea that what we have now is closer to normal, we'll be much better off.

    • by D Ninja (825055)

      administration's fault in 3.....2......1....blastoff.

      Won't happen. We don't have any rockets for a successful launch because the U.S. Space program is dying.

    • by grumpyman (849537)
      X Prize did push this sector from a private angle.
  • by Firehed (942385) on Thursday June 10, 2010 @06:35PM (#32529366) Homepage

    Seriously. If you're going to make a real-life attempt at a Bond plot, at least change the name of your giant solar sail.

  • by hadesan (664029) on Thursday June 10, 2010 @06:42PM (#32529460)
    One question, how does it stop with no fuel (aka an ability to brake?)

    Also, how well does the membrane hold up to minuscule debris? Is it durable for extended voyages (outer solar system, extra solar)?

    What is the maximum velocity it could reach with the available solar wind prior to it ending at the heliosheath?

    If they could combine it with something to scoop up stellar gas, along with something to process the gas into energy for steering and braking, you would have something useful.

    And please no Uranus comments for my subject line...

    • by SixAndFiftyThree (1020048) on Thursday June 10, 2010 @07:05PM (#32529694)

      How does it stop? If it accelerates tangentially to the Earth's orbit, which is still the most efficient way to get to another planet, then it can decelerate by tilting the sail the other way. In each case, the acceleration vector will have a component outwards from the Sun; the ways to cancel that include furling the sail and waiting for the Sun's gravity to do the job, using a nearby planet's gravity, aerobraking in a nearby planet's atmosphere, or lithobraking. If none of the above work, then perhaps you can't stop. A bizarre scheme that has been suggested would be to bring a second, smaller sail along and use it to collect light reflected from the main sail towards the Sun (you cut the main sail loose and let it drift ahead of you), thus providing reverse thrust until the main sail is too far away. Hard to be sure how well this would work.

      Debris hitting the sail? A few pinholes will make no appreciable difference to its performance. A real sail would have to be made with some sort of "ripstop" reinforcement.

      Max speed? You have a misconception here: solar sails don't use the solar wind (much), but the pressure of the Sun's light. Since e=mc2, momentum equals e/c. I don't have the formula handy, but the important factors are the thickness of the membrane (thinner is better) and how close to the Sun you start (closer is better, provided the membrane doesn't melt). In theory, solar escape speed is attainable, if you're only pulling a small payload. Significant fractions of the speed of light are not attainable.

      Scooping up the gas would need one **** of a scoop!

    • by toygeek (473120)

      One question, how does it stop with no fuel (aka an ability to brake?)

      Flip it around at the half way point. Rockets. Solar parachute? That's question 1.

      Also, how well does the membrane hold up to minuscule debris? Is it durable for extended voyages (outer solar system, extra solar)?

      I thought you said you had one question. It would hold up just as well as a sailboats sail would with thousands of micro tiny itsy bitsy holes in it. Just fine, thanks.

      What is the maximum velocity it could reach with the available solar wind prior to it ending at the heliosheath?

      Hmmm this is three questions. I'm beginning to question the validity of your inquiries based on your lack of ability to count. The real answer to your question is yet another question: "Laden or Unladed?"

      If they could combine it with something to scoop up stellar gas, along with something to process the gas into energy for steering and braking, you would have something useful.

      At last, a statement instead of yet another question. A st

    • by DowdyGoat (1830958) on Thursday June 10, 2010 @07:39PM (#32530100)

      NASA had a proposed "Interstellar Probe" mission that was to use a 200 meter diameter solar sail to travel 200 AU in 15 years (the heliosheath, or edge of the solar system, is about 100 AU from the Sun). It was thought they could keep contact until 400 AUs distance. Link (go to the Interstellar Probe Report link there):

      http://interstellar.jpl.nasa.gov/

      This mission, as well as a proposed follow up mission (I think called Interstellar Probe 2) that would have had a bigger sail, gone twice as fast, and reached around 1000 AU, were both shelved quite a while ago. (There was a single NASA page on that second mission a long time ago, but I cannot find it now.)

      You could use probes like these to sort of act as galactic weather probes, testing the interstellar space that our solar system would encounter in coming decades/centuries and seeing how that "interstellar weather" affects the Sun the the Earth's environment as we pass through it.

      A theoretical improvement on a solar sail would be a "light sail"--you could set up satellites with powerful laser systems orbiting the Sun and use that focused and powerful light to push sails much faster. Some folks have hypothesized reaching 10% to 30% the speed of light using techniques like this if the lasers were powerful enough and coordinated enough. Assuming success, you could possibly send an unmanned probe to Alpha Centauri in a matter of decades. In this instance, you could theoretically use a solar sail to use the solar wind/light of the Alpha Centauri system to slow down once you started nearing it (although that could potentially add more travel time).

      Things like these could be a relatively fast, cheap, and safe (as compared to nuclear) way to explore our external solar system (Kuiper Belt) and nearby interstellar space (Oort Cloud), and get a good handle on how our surrounding interstellar space affects our solar system. Very interesting stuff. I hope more of it happens!

  • Better Articles! (Score:5, Informative)

    by BJ_Covert_Action (1499847) on Thursday June 10, 2010 @06:52PM (#32529568) Homepage Journal
    Oh for fuck's sake why do we keep linking to Inhabitat for news on space missions? The Ikaros project is, indeed, a newsworthy and exciting piece of nerd information. However, linking to a stupid environmental blog that holds informational gems like:

    "Solar sails offer the best hope for deep space exploration because they eliminate the need to carry fuel." (Hint: No, they don't. They don't do that at all. You need maneuvering thrusters to align your spacecraft before deployment. You need a power source to provide electricity to power your control motors when you get too far away from the sun. Saying solar sails eliminate the need to carry fuel is like saying that a spoiler eliminates the need for a gas tank on a car because it improves gas mileage. That is a completely asinine statement.)

    And:
    "spacecraft — unlike airplanes — don’t have to contend with drag," (Also untrue. Depending on what orbit/space environment you are in, you may still have to contend with the drag of Earth's atmosphere. If you are deploying in LEO, this could induce a significant moment on your spacecraft. Also, thank you for pointing out the difference between aircraft and spacecraft...that was really weighing on my mind while reading about a spacecraft mission that is proof-of-concepting a new technology).

    And:
    "Of course, aliens aren’t the only reason to want to travel through space without carrying rocket fuel. NASA is also working with solar sails to develop ultra-efficient spacecrafts. " (Aliens and ultra-efficient spacecrafts eh? That's your high-quality independent journalism right there? Give me a break this kind of stupid babbling about a very important mission does nothing but patronize the spacecraft industry and the folks who worked on this particular bird).

    Let me give you a hint Inhabitat readers, if you want to track the progress of an impressive space mission, try going to a news site that actually is focused on space. Maybe you should check out: Centauri Dreams [centauri-dreams.org] or one of JAXA's [jspec.jaxa.jp] own website's [www.jaxa.jp] regarding the hardwork and impressive design that went into designing this mission. Perhaps you should read and link to some articles that actually contain interesting, relevant, tech-centric discussions of the mission rather than your latest, retarded, three paragraph, juvenile blog whose most interesting mission detail: "....allowing it to launch the .0003-inch-thick sail," borders on painfully irrelevant.

    /endnerdrage
    • Re: (Score:2, Informative)

      by MMatessa (673870)
      I also came here to complain about the poor article. Good coverage comes from the blog of the Planetary Society [planetary.org], which is working on its own solar sail and actually has people visiting JAXA.
  • I always thought that it would be NASA that would be the first to announce the discovery of extraterrestrial life. Now i'm thinking Japan may have that honor.

    As a side note, maybe this will spark a new "space race". That would be probably be a good thing at this point.

  • Thank you Slashdot. (Score:3, Interesting)

    by CrazyJim1 (809850) on Thursday June 10, 2010 @06:57PM (#32529618) Journal
    I want to hear stories like this. I want to know if Solar Sails are viable. Back in highschool I wondered about a space ship propulsion device. My theory was to make particle accelerators to get the maximum propulsion out of hydrogen atoms and fire them out the back of the craft. The problem was you could run out of hydrogen. Its not something serious, but just trying to figure out something better than rockets. The solar sail sounds like it is plausible, and I'll be excited to hear this story develop. The last thing I was excited about was the Mars Rovers. How cool were those.
    • Re: (Score:3, Interesting)

      by TooMuchToDo (882796)
      Why not use magnetic fields to scoop hydrogen from in front of your craft and accelerate them out the back using a particle accelerator/cyclotron. This could be powered via solar near our/other suns, or nuclear RTGs further out. Similar to an ion drive, but without the need to carry the propellant.
  • ...unlike airplanes — don't have to contend with drag, so with each photon that hits the sail helps the spacecraft gather speed.

    Sorry, but I have complex instruments telling me that not only will there be drag, but that it will increase as the sail recedes from it's current solar power supply. My instruments are my eyes, and they tell me that a lot of the photons arriving here are going the wrong way to propel anything away from earth. You can verify my work by going to an unlit location on a clear night and taking note of all the starlight striking your eyes... Those are the wrong way photons and the weaker our sun shines on the s

  • Solar sails get less practical the further you go out from the sun due to the inverse square law. Somewhere between Mars and Jupiter is about the accepted limit. Certainly not useable for exploring Uranus and Neptune for instance. You can define "deep space" many ways but inner solar system isn't one of them.

    • by blair1q (305137)

      They'd better define it as this side of the oort cloud, because getting through that without powered guidance is a crap-shoot.

      • > They'd better define it as this side of the oort cloud, because getting
        > through that without powered guidance is a crap-shoot.

        The density of material in the Oort is so low that you would have to pass through it thousands of times to have an appreciable risk of hitting anything.

  • Looking at the photos in the referenced article, the fourth picture, showing the solar sail fully extended with all kinds of nice wonderful colors (photo from a perpendicular angle) cannot have been shot from the same camera as the other photos. Different color saturation, different focus, different depth, different starfield luminosity, a rather idealized picture of the earth. Offhand, I think this is an artistic or fictional or Photochop representation, and, it is not labeled as such.

    It's nice that the Ja

  • have to contend with drag, so with each photon that hits the sail helps the spacecraft gather speed."

    Only a very novice astrophysicist would ignore the fact that such a large sail is going to plow through dust too. And how many photons do you think it will take to counter the effects of even a small grain of dust, when the dust is stationary and you're clipping along at hundreds of km/sec? (or vice-versa for that matter - you could quite conceivably get hit by a spec of dust traveling at some fraction of c

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