Japan To Launch Solar Sail Spacecraft "Ikaros" 138
separsons writes "On May 18th, Japan's Aerospace Exploration Agency (JAXA) will launch Ikaros, a fuel-free spacecraft that relies completely on solar power. The spacecraft's 46-foot-wide sails are thinner than a human hair and lined with thin-film solar panels. After a rocket brings the craft to space, mission controllers on the ground will steer Ikaros by adjusting the sails' angles, ensuring optimal radiation is hitting the solar cells. If the mission proves successful, the $16M spacecraft will be the first solar sail-powered craft to enter deep space."
Icarus? (Score:5, Funny)
It's always seemed like a bad idea to name anything after a figure whose claim to fame was that he ignored warnings against exceeding the tolerances of his vehicle, causing it to break up and kill him.
Re:Icarus? (Score:5, Funny)
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This whole thing is so Anime-esque I can barely stand it. Not only does it have an unfortunate name, but it's an English acronym, the name is pulled from classic Greek... Now all we need is some Shirow suits and we've got a movie.
Re:Icarus? (Score:4, Funny)
Re:Icarus? (Score:4, Informative)
This thing goes away from the Sun, not nearer it.
Nope. Tilt the sail so there is thrust against the direction of orbital motion and the ship will fall inward toward the sun. Think of the spacecraft with the sail at 45 degrees to the radial direction ot the sun, so light is reflected along a tangent to orbit in the direction of motion.
So long as a solar sail craft is in orbit, it can either raise or lower its orbit more-or-less at will, although it is easier nearer the sun than further out. Once it is out of orbit, however, it can't ever return.
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Not sure about that. I've seen claims that a lot of the thrust of a solar sail would be due to the solar wind...which would tend to stick, and thus couldn't be tacked against.
Also, solar cells tend to absorb photons, capturing their momentum, and when they re-radiate it (at a lower frequency) the direction is random.
If this is correct, then the simple model of solar sails tacking using reflected light is at least an oversimplification, and possibly so much of an oversimplification that it doesn't properly
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Not sure about that. I've seen claims that a lot of the thrust of a solar sail would be due to the solar wind...which would tend to stick, and thus couldn't be tacked against.
Those claims are wrong. The force on a solar sail due to solar radiation pressure is about a thousand times that of the solar wind.
Also, solar cells tend to absorb photons, capturing their momentum, and when they re-radiate it (at a lower frequency) the direction is random.
The solar cells are going to be absorbing a small fraction of the incoming photons. If the sail is designed properly, the rest will be reflected in a controllable direction.
If this is correct, then the simple model of solar sails tacking using reflected light is at least an oversimplification, and possibly so much of an oversimplification that it doesn't properly predict the effects.
Your assumptions are wrong, and the model is correct.
MESSENGER has used its mostly reflective solar panels to make deliberate course changes. The basic physical principle is already proven, not just in the la
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The efficiency isn't changed much by having a few holes punched in the sail, and meteors actually do less damage to the sail than they do to something thicker. The sail doesn't stop them, so they don't turn into heated balls of vaporized stone. Generally that hole caused by a meteor in a resistive craft is several times the size of the meteor. If it leaves a pit an inch across, the original was probably smaller than a pinhead. (This is just my rough guess...I don't know enough to calculate it...but figu
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Creativity points, though, for coming up with a name whose acronym gives the Greek spelling "Ikaros". I've always hated Latinized spellings or names for Greek mythological characters.
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The Latin spelling is Íkaros. So they are using the Latinized name.
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I highly doubt the Latins used "Ikaros" very often. Maybe when they were referring to the Greek. Ovid certainly used "Icarus": http://users.telenet.be/daedalus/Ovid/DaedIcar.htm [telenet.be].
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The spelling "Icarus" is derived from the Etruscan spelling which was Vicare.
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That's possible, but I would doubt it. Greek words and names were usually transliterated by the Latins with "c" for Greek kappa (and "us" for cases with Greek second-declension masculine[omicron-sigma/"os"]). And this was done even after Etruscan had gone extinct. Maybe the tradition of transliterating as such came from the Etruscans, I don't know.
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Shouldn't your name be "SputnikPanik" then?
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Isn't that Apple's new product?
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iKarOS?
Sounds like an open source project to replace the faulty code in the oft crashing Toyotas. Using a Darwin kernel.
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It's always seemed like a bad idea to name anything after a figure whose claim to fame was that he ignored warnings against exceeding the tolerances of his vehicle, causing it to break up and kill him.
Yeah... "Daidalos" would have been a better name I would think. Or "Daedalus" if you prefer Latin spellings (which I assume you do, since you titled your post "Icarus" instead of the more accurate to the original Greek "Ikaros").
Gloster Meteor! (was: Re:Icarus?) (Score:2)
As in, "Those things that, every time you see one, it always seems to be falling out of the sky in a screaming ball of flame before smashing into the ground".
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Of it can refer to the physically impenetrable Walls of Troy which were only breached through cunning trickery...
Much like when she takes all your condoms and secretly pokes holes in them through the packaging so that she can have your baby... actually that's more likely to happen the other way round but anyway.
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Sounds like a reminder, too. "Fly this puppy too close to the sun and your wings will melt off and you'll turn into a rock."
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Daedalus flew too close to the sun, melted his wings, and died.
His father, Icarus, the creator of the wings, then landed and never flew again in mourning over his son, who's death Icarus was in part responsible for.
Mythology fail! Icarus [wikipedia.org] flew too high and fell.
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-1 Exactly Backwards.
http://lmgtfy.com/?q=daedalus+and+icarus/ [lmgtfy.com]
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Was that before or after Laius killed Oedipus and married Jocasta?
Thin sails (Score:2, Insightful)
Won't that easily break if something even touches it? (lots of space rock going a few km/s out there, or am i totally off?)
Re:Thin sails (Score:4, Insightful)
Well yeah, but you could make it 100x thicker and all that debris whizzing around would still poke holes in it. This way, it's light enough to be a.) cheap to launch and b.) actually efficient enough at harnessing the solar "wind" to move its mass.
Re:Thin sails (Score:4, Informative)
...harnessing the solar "wind" to move its mass.
I guess you didn't mean this, but just to avoid confusion. There is something called "solar wind", charged particles ejected from the sun, it has nothing to do with this sail. The sail uses light pressure, the pressure of light emitted by the sun.
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I guess you didn't mean this, but just to avoid confusion. There is something called "solar wind", charged particles ejected from the sun, it has nothing to do with this sail. The sail uses light pressure, the pressure of light emitted by the sun.
I'm pretty sure it uses both, seeing as how both light and charged particles will impart momentum to the sail when they hit it. Ihe solar light pressure is larger, so it's accurate to say it's powered by light pressure. But the solar wind does have something to d
Re:Thin sails (Score:5, Insightful)
No, I suspect that's an expectation, but if the materials are built right it'll have some rip-stop capability so it'll just make a hole. That will affect the solar sail, but not significantly until you get a lot of them.
The alternative is to make something that is heavier and less effective, which will still get punctured if a bit of debris goes through it.
After all, things in space are usually not moving very slowly in relation to each other, so anything that touches it is likely to go right through anyway, regardless of the material. I suppose with something like this, the less resistance the material puts up the less its course is going to be screwed up by a space rock.
It's also relatively unlikely (though certainly not impossible) for them to have a strike in the first place. Look at how cluttered Low Earth Orbit is with Mankind's crap, and how many active satellites have ever been knocked out of commission by our own cesspool of concentrated garbage in LEO? Two that I recall, and they hit each other. I know there have been occasional stories about impacts, but they aren't terribly common, and the chances of them dwindle off rapidly past LEO and Mankind's junkyard.
Plus, $16 million?!? for a deep space probe that requires no fuel? That's chicken feed in terms of space travel. The Japanese could probably mass-produce them for $12 million a pop or less given economies of scale, send 10 of them out in different directions, lose 8 of them to debris strikes and whatever, and STILL get better science longer than pretty much anything short of nuclear we could send up today.
Mankind's Junkyard (Score:2)
itself: "Mankind". Basically, it's made up of two separate words -
"mank" and "ind". What do these words mean ? It's a mystery, and that's
why so is mankind."
-Jack Handy
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Basically, it's made up of two separate words -
"mank" and "ind". What do these words mean ? It's a mystery...
Well, I don't know about "ind", but for mank [wiktionary.org]:
mank
1. (British, slang) disgusting, repulsive
When he eats, he never closes his mouth. It's so mank
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Sure, but 46 feet wide is a pretty small target in the vast, empty vacuum of space. Beefing up the thickness wouldn't make it tough enough to resist impacts at the velocities that space rocks would be hitting it at anyway. And if an object with mass hits your solar sail, probably it's better for it to punch clean through and impart as little kinetic energy into your vehicle as possible, so that it doesn't get knocked off course as badly.
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I don't know anything about this project, but one strategy for handling micrometeorite impact in large deployed thin-film solar panels (which is what these sails really are... plus "steering mechanisms"... thin-film ion drives?) is to deliver massively more sail area than is required, and to use a grid network design in the sails themselves such that power is carried through highly redundant parallel paths. If you lose a large percentage of the total sail area, you still retain the ability to operate. Nanos
Re:Thin sails (Score:5, Informative)
Yes, you are right -- micrometeoroid impacts are definitely an issue that you have to deal with when you are using thin-membrane materials in space. Hopefully the engineers will design features called "rip stops" (among other names) into the sail to prevent tears from spreading through the sail. These are usually accomplished by putting a grid of perforations throughout the sail -- when a tear encounters one, the circular shape spreads the tensile stresses across the adjacent material, reducing the likelihood that the tear will propagate. This way a micrometeoroid impact won't ruin your entire sail, just the local grid element.
There are probably other methods of implementing rip stops, but I haven't read any significant literature on them. Anything bigger than a micrometeoroid, and you have bigger problems -- but in this case, a traditional satellite would have just as big a problem.
Aikon-
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Macroscopic objects are extremely rare (even microscopic objects are rare). Space is mostly, well, empty. The craft will cover some space, so it's expected to encounter something, but nothing big. The Sail can't be thicker, the sail area to mass ratio is what defines the efectiveness of the sail. As long as tiny holes in it won't cause it to collapse in some way or tear down, I can't see any problem.
Even if it's destroyed, it's very cheap...
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I believe that "Saran Wrap" is about this thin, but you still trust it to protect you from the mold growing on the leftover beans in your fridge. Thin doesn't mean it has to be extremely fragile.
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You're thinking about it wrong. They've seriously reduced the odds of side-impact damage with this clever thinner-than-hair technology. Glass half full, right?
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Well , they will certainly melt if they get too close to the sun , that's for sure.
meh (Score:5, Funny)
the bjorans did this centuries ago :)
repeat
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the bjorans did this centuries ago
While I enjoyed this episode of DS9, it really wasn't clear to me how this Bajoran ship left Bajor's surface, did a de-orbit burn to start its journey into space and then did a re-entry onto Cardassia. They conveniently glossed over that piece.
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That's true, but even in terms of Trek, you can't help but wonder why when Sisko recreated a Bajoran lightship, he had the ship launch from a space station, instead of the surface of Bajor. He was supposedly going for a almost genuine (with the exception of zero g) experience afterall.
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If you want overly technical scifi-babble about the technology and methods used in Star Trek, I suggest you watch Voyager instead. The stories aren't nearly as good, but they use lots of $2 words.
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$2 words???!!! I thought you were supposed to watch Voyager because of 7 of 9...
So, give him partial credit for getting '2' right, then.
Rather irrelevant... (Score:2)
The point was that Bajorans have made it to Cardassia long before either species had developed warp technology.
Kinda like as if Ikaros would suddenly made it to Alpha Centauri in a matter of minutes. And found Na'vi there.
Whether Bajorans used chemical rockets, space elevators or giant catapults to get their solar-sail ships to space in the first place is rather irrelevant compared to that.
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And NASA first used light pressure in an interplanetary probe decades ago... Mariner 3 [wikipedia.org] and Mariner 4 [wikipedia.org] both used light pressure to assist in controlling attitude during the trans Martian cruise phase of their flights. (That's what the paddles on the end of the solar arrays are for.)
It wasn't used on later Mars missions because the craft became too large and heavy to use that method.
Which is the real drawback of light pressure sails - from a purely mathematical standpoint they're the most eff
Coolness Factor and Project Name (Score:3, Funny)
Very cool project, I can't wait to see this baby in action!
That said, someone already mentioned the project vehicle name, but we all know it should have been Odin: Photon Sailer Starlight.
I suddenly feel very nerdy, much more so than normal.
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Are you suddenly speaking more fluently in Javascript or Klingon?
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I just had a conversation over IM in regex patterns about Jack Kirby, there is no hope for me now...
What could possibly go wrong? (Score:1, Troll)
"The craft's 46-foot sails come equipped with solar cells thinner than a human hair. When solar particles hit the cells, they generate power for Ikaros. Mission controllers on the ground will steer the craft by adjusting the sails' angles, ensuring optimal amounts of radiation are reaching the solar cells."
What could possibly go wrong?
Re:What could possibly go wrong? (Score:5, Insightful)
1) try > succeed > learn
2) try > fail > learn
Given the amazing low price tag for the mission, both are good outcomes.
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Uhhhh, not much? If the craft fails then they are only out a few million, same thing that happens when any other spacecraft fails (except they are usually far more expensive).
Generally we try to reserve the "What could possibly go wrong" meme for things that reek of a bad idea, like making walking titanium skeletal robots, giving them machine-guns and Austrian accents, then turning over control of them to google. Space sails are a pretty simple and much discussed idea, and lack any particularly bad failur
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Well...
If they're large enough you could use them to burn down cities and wipe out food supplies, but I guess we already have pretty effective ways of doing that.
Preparation (Score:5, Funny)
This has to be a bad joke... (Score:1, Flamebait)
You know the only reason the Japanese named it Ikaros instead of Icarus is so they could finally laugh at us mispronouncing something for once. Wow, the Abbot and Costello routine around this one almost writes itself....
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You would be right if they were aiming for the name in english. Íkaros is his name in latin.
At least its easier to write than greek: , which Slashdot can't even parse...
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Sadly, the linked article... (Score:2)
...is so infested with bad JS I can't view the actual text in FF. Anyone have a working link?
A Mote in Gods Eye (Score:2, Informative)
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Man I hope not, those Moties were pretty terrifying.
Fantastic book though, I should read that one again.
$16M seem cheap? (Score:2)
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I'm thinking that $16M does seem rather low, but I would expect the cost to be significantly less than a shuttle launch. The shuttle is pretty big, very heavy, and also has to carry and keep alive a bunch of people through launch, orbit, and return. This solar sail is designed for a much simpler set of tasks, and likely weighs in at a small fraction of what a shuttle orbiter does.
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As the article implies, the $16M price tag is the price of the ship, not including the price of using it. Given that it's being sent up as a secondary launch for another mission the price of using it should be pretty low.
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Tachyon Eddy (Score:5, Funny)
Now all we have to do is find a tachyon eddy and we could be on Cardasia in no time.
Is it just me or is Japan's space program awesome (Score:5, Interesting)
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That's an excellent attitude and it (unsurprisingly) mirrors my own thoughts on Japan's space program. They're doing *cool stuff* that can spark the imagination. And they're doing it for amazingly reasonable sums of money.
man who says impossible shouldn't interrupt man wh (Score:2)
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I'm sure there's plenty of pork. But this being Japan, it's raw and wrapped in seaweed with vinegar rice.
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But they recently landed a probe on an asteroid, and returned it to earth with asteroid rocks
Well, not exactly. They sent a spacecraft to an asteroid to hover above the asteroid, shoot a pellet at it, scoop up some debris, and come back. Instead, part of the system failed. The spacecraft landed to preserve its health while possible fixes were discussed. The landing caused the pellet shooting system to fail so no asteroid debris was collected for sure. The Japanese decided there was still some chance that something, somehow, ended up in the collection bin. They uploaded some patches to the spacecra
Inhabitat Articles (Score:4, Insightful)
I guess what I am getting at is that just because Inhabitat stumbled upon something cool they didn't know existed, it doesn't mean there is any news regarding that particular item. Now, if Ikaros launched recently, or if it's mission was underway, or if it was experiencing some technical difficulties, that would be something. The fact that the mission exists in the first place is neither a recent development nor particularly newsworthy. It seems like the firehose is getting clogged with Inhabitat submissions and frankly its starting to seem like slashvertising for the blog.
How fast does it go? (Score:1)
Minmatar Frigate, anyone? (Score:2)
I'm surprised that there hasn't been a single EVE reference to this project yet.
Soon as I saw this project, I thought, "It's like they're developing a Minmatar frigate [eveonline.com] of some sort!"
With that in mind, I genuinely hope that this project exceeds expectations, and that we may see more projects like this in our near future. Good luck and best wishes.
Two words (Score:2)
Name FAIL
That name! (Score:2)
Calling it the Ikaros is sort of like calling a new ship you build "The Titanic". It doesn't do a lot to inspire confidence.
Here's to hoping to works for them though, it's definitely ambitious and way cool.
deep space (Score:2)
spacecraft will be the first solar sail-powered craft to enter deep space
Depends on your definition of "deep space". I understood that to mean outside the solar system. A quick googling shows two definitions: 1. interstellar 2. interplanetary and beyond. So definitely not clear. In any case, it's somewhat moot since there's never been any solar sail-powered craft, ever, that succeeded in deploying its sail. Even in Earth orbit.
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I think it is mistaken on some of the details. A solar sail works by being pushed by photons, just as a regular sail works by being pushed by the wind. A solar panel collects light and turns it into electricity. And solar panels are much thicker than a human hair. I don't doubt that it does have some solar panels but doubt it is as much as the article seems to imply since the panels are still much weightier than a solar sail needs to be.
Re:Solar power in deepspace (Score:4, Informative)
A solar panel collects light and turns it into electricity. And solar panels are much thicker than a human hair.
A solar panel is anything flat and, in this context, photovoltaic. The part of a typical solar panel where the magic happens is much thinner than a human hair; it's the junction between two materials. The rest of it is just there to protect that part (and to enable its production during manufacturing, of course.) But since thin-film solar panels have been around for more than a little while, you have no excuse for not knowing about them and yet simultaneously "contributing" to this discussion. Thin-film panels are now cost-competitive with crystalline panels and are expected to eventually be much less expensive due to their reduced energy cost of manufacture. This also reduces the time to energy payback, which was around seven years with crystalline panels in the 1970s. (I have GOT to find my source on that again, must be in some old homedir someplace...) And in space, nothing non-structural has to hold up its own weight or survive winds (aside from the solar wind) so it can be as thin as will provide sufficient tensile strength. Like, say, a sheet of plastic.
A solar sail converts photon impact to momentum. Anything photons are absorbed or reflected by is a solar sail. A solar panel converts a portion of photon impact to electricity, trading photon velocity for electron velocity. These are not incompatible goals. As far as I understand, a reflective solar sail actually imparts more velocity than an absorptive one, but both work.
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Both work, but they have different operating characteristics. An absorptive solar sail can only impart velocity directly away from the sun. A reflective solar sail can impart momentum at an angle, because the angle at which the photon leaves the sail also imparts momentum.
Unfortunately, both kinds are affected by the solar wind (which is usually approx. directly away from the sun, but can vary wildly when it's distorted by magnetic fields. And which can't be tacked against, unless you charge your sails s
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Unfortunately, both kinds are affected by the solar wind (which is usually approx. directly away from the sun, but can vary wildly when it's distorted by magnetic fields. And which can't be tacked against, unless you charge your sails sufficiently with a charge opposite to that of the incoming wind...and maybe not then. (Even if this would work, it's impractical.)
Nonsense! Simply build a keel of conductive material on the spacecraft that will give the ship a preferred direction of motion through the Lumini
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Simply build a keel of conductive material on the spacecraft that will give the ship a preferred direction of motion through the Luminiferous Aether and you can tack 'upwind' as easily as you tack up a river!
Generally speaking, having a surface charge on your spacecraft is dangerous. It tends to induce errors in the internal electronics and it can also enact a magnetic moment on the spacecraft itself. Of course, if the surface charge can be modeled in advance then such effects can be accounted for, but that adds a whole new layer of complexity to the design.
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You know, I'm thinking there just might be an additional problem or two with my "space keel" idea. :)
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They have a flashlight mounted under the solar sail to provide the becessary light when they get too far from the sun. That's why they need the solar panels, to provide power to the flashlight when it's too dark for the sail to work otherwise, which also powers the solar cells.
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The xkcd blog had an entry about this [xkcd.com] a while back. it showed that in combination with a large mirror to reflect the beam several times, you get several orders of magnitude in efficiency improvement.
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Re:Where's it going? (Score:4, Informative)
Anyone know where it's going? "Deep space" isn't much of an answer, as it includes everywhere that isn't Earth. Does it have a destination besides "away"? The article does not say...
As far as I can tell, it's an experiment to test the propulsion system with no other purpose. Here's a slightly better article [physorg.com] about it.
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As far as I can tell, it's an experiment to test the propulsion system with no other purpose. Here's a slightly better article [physorg.com] about it.
Then what a waste. Seriously.
One thing I admire about NASA is its ability to pull in secondary and tertiary missions. If you're just going to send it flying, at least put on a simple camera and send it somewhere useful. Fly by the outer planets, or visit the asteroid belt, or try for a comet or KBO. Surely there's at least one object in the solar system within range for simple observations.
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Earthquakes, Volcanoes, Climate Change, Wars, Plaques, vanishing bees and the possibility that George Lucas might make another movie? All of these are signs that the 4 Horseman are saddling up and getting ready for a ride.
So "away" is good enough for me.
Hopefully to a planet that was not colonized by the Golgafrincham B Ark.
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With a name like "Ikaros", it's obviously going to have a parabolic flight path.
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Ever see "Star Trek: The Movie"?
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As the term "deep" harbors pornographic connotations, I'd wager it's heading toward Uranus.
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