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Solar Sails And Space Propulsion
Doomie writes "The Economist has an interesting article about solar sails. It talks about the Russian ICBM that will launch Cosmos 1 (mentioned previously on /.) 'The first craft powered by solar-sail technology to orbit the Earth', and the link between this technology and interplanetary travel. Cosmos 1 will orbit Earth starting on June 21st and could, in theory, reach '200,000kph after three years of acceleration' due to the fact that 'particles of light, or photons, that strike a surface give it a tiny push'. The official homepage of the project has more details." Update: 06/18 18:57 GMT by Z : While space trains would be cool, that wasn't the intent of the story. Changed rails to sails.
Solar rails???
New web development venture?
Space trains?
L. Ron Hubbard was right?
Get your Unix fortune now!
These solar sails really blow!
Isn't this supposed to be a professional website? I'm not the first poster, I realise, which means I'm certainly not the first person to notice the spelling error. But... hasn't this gone past an editor? I mean... what is going on here. Every post has an error of some kind... spelling, grammar... anything...
I'd offer my services as a proofreader but I don't think I want to be associated with something so consistently shoddy...
Slashdot has Ruby on Rails on the brain...
Union Pacific is to build the ship?
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
Sail of the century
Jun 16th 2005
From The Economist print edition
One small step into orbit may be one giant leap for interplanetary travel
Rick Sternbach, The Planetary Society
ON JUNE 21st, a Russian nuclear submarine is due to launch an intercontinental ballistic missile (ICBM) from beneath the surface of the Barents Sea in the Arctic Ocean. Fortunately, this will not be the opening volley in a global thermonuclear war. Rather, it is intended to open up a new age of space exploration.
The ICBM's payload is Cosmos 1, an experimental spacecraft being launched by the Planetary Society (a space-advocacy group founded in 1980), in conjunction with NPO Lavochkin (a Russian firm which built the craft) and the Makeev Rocket Design Bureau (which modified the ICBM). If the mission, which will cost $4m and has been paid for entirely by private subscription, is successful, Cosmos 1 will become the first craft powered by solar-sail technology to orbit the Earth.
Solar sails rely on the fact that particles of light, or photons, that strike a surface give it a tiny push. Ideally, such sails should be as big as possible, to maximise the amount of sunlight collected, and as reflective as possible, because a photon bouncing off a perfectly reflective sail produces twice as much thrust as one absorbed by a non-reflective sail. Even so, the thrust generated is tiny: a sail with an area of one square kilometre would feel the same force that a kilogram weight exerts on a table on Earth. But there is no air resistance in the vacuum of space, and the sun shines continuously. Slowly but surely, the light-propelled tortoise outruns the rocket-driven hare, reaching 200,000kph after three years of acceleration.
The Planetary Society has details of the forthcoming launch of Cosmos 1. The Makeev Rocket Design Bureau modified the ICBM which will carry the craft.
Solar sails would thus be especially useful for journeys to distant planets or vastly more distant stars, as they do not need to carry any fuel with them. But while they have lived in the imaginations of scientists and science-fiction writers for over a century, their track record in real life has been limited. The Japanese Aerospace Exploration Agency has tested the unfurling of solar sails on sub-orbital rockets, but no one has put solar sails into orbit. Cosmos 1 should change that and, if it works, it will prove the feasibility of the technology for future missions.
Eight triangular sails arranged like the petals of a flower will propel the craft. Each of the sails is 15 metres long, and in total they span 600 square metres--roughly the size of the penalty area on a football pitch. During launch, the sails will be rolled up like so many sleeping bags. Once the ground crew has decided that the craft is in a stable orbit, though, a series of tubular "masts" will be inflated that will unfurl the sails as they expand.
Solar sails require special materials if they are to reflect sunlight efficiently while weighing as little as possible. They must also be able to fold up easily into a small space. Cosmos 1's sails are made from plastic sheets just five microns (millionths of a metre) thick. That is about a quarter of the thickness of a plastic dustbin liner. The plastic in question, Mylar, is coated with aluminium to make it reflective. Mylar is perhaps more familiar from its use in helium-filled party balloons.
If all goes as planned, the spacecraft will go into an orbit that flies over the Earth's poles. Four days later, the sails will be deployed. Once this has happened, the team will monitor Cosmos 1's altitude. The sails are able to swivel slightly, and the ground crew can tilt them individually in order to catch the most sunlight. The resulting increase in the altitude of the orbit will indicate that the sails are indeed feeling the sun's push.
Provided all this works well, the team will then try one last experiment. In order to use solar sails to travel to the outer planets, where the sun's l
Whoever posted the link to the Article failed to comprehend the fact that I have to pay and register to view it - so please why don't you also publish your username and password so others can also see it.
/.ers are rich enough to afford to pay for the thousands of rip-off subscriptions.
Not all of us
200,000kph = 200,000 km/h
The similarities are striking, in that with both solar rails and solar sails, you don't have much option what direction you want to go.
When can I buy my first-class tickets on the Starship Titanic?
Now all they need to do is hit a tachyon eddy and we can reach Cardasia
The only things certain in war are Propaganda and Death. You can never be sure which is which though
So..this sail will orbit earth?
What about all the space debris that will rip the hell out of the sail?
I don't think that the sail will last anymore than someone throwing a paper airplane in the air and have a firing squad shoot at it until their is no more. Lets see that plane fly for 4 years
$sig$
I have always been facsinated by the idea of solar sails. Something about them seems so elegant and simple. The idea of branching from sailing ships to sailing starships just seems so right to me.
I don't think Union Pacific builds their own equipment anymore. But maybe General Electric or Electro-Motive / GM EMD could provide build the ship.
Hmm, I can't seem to find the "Add To Shopping Cart" button on either of those websites. Internet shopping revolution my foot!
Darn, I was in the middle of preparing a submission on Cosmos 1 when I saw this. Anyways, I have a little more info which people might find interesting, so I'll go ahead and paste it below:
Countdown to First Solar Sail Spacecraft
The Planetary Society's Cosmos 1, the first spacecraft to be propelled by a solar sail, has just been loaded onto a converted ICBM in preparation for its launch from a Russian submarine this Tuesday, June 21. This is the first mission by a non-profit space advocacy group and is being funded by private donations. Project Operations Assistant Emily Lakdawalla is posting a running description of events on the official blog. Videos and animations describing the mission are available, including commentary from the Planetary Society's Vice President, Bill Nye the Science Guy. Downloadable print-out model kits are also available.
One of the many neat things about this project is that if the first phase of regular solar sailing is successful, they'll run a later experiment with focusing a microwave beam on the sail to see how well it propels the craft. I wish the Planetary Society the best in this high-risk endeavour.
What about using a giant rail-gun to launch a space vehicle from the moon?
Once spaceborn, the vehicle could deploy its deep-space propulsion, such as solar sails or ion drive.
Raise your children as if you were teaching them to raise your grandchildren, because you are.
Can't post without a "body". Stoopid /.
Check out this week's Quirks and Quarks podcast, which covers the same topic. They interview the Planitary Society project manager about the upcoming solar sail launch.
While I'm at it, they've also got a segment on quantum cryptography this week which is kind of interesting.
ENDUT! HOCH HECH!
Am I missing something? Is that two hundred thousand thousand per hour? What are the units?
GENERATION 25: The first time you see this, copy it into your sig on any forum and add 1 to the generation. Social exper
Its about a training voyage with six cadets and a instructor who thorougly trains his cadets by making the voyage a living nightmare of failures, as well as making sure they make it on their own ( as he's already seen to it the radio does not work, and he's let it be known very clear to the cadets he expects to die in space - the ship is theirs to navigate using the forces of nature at their command, and he's not lifitng a finger to help.).
Jack seems to have his physics pretty accurate -
I have re-read that story often. It would make a helluva movie.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
I'm unclear as to how energy is conserved in this case.
Clearly the energy of the reflected photon must be less than the incident photon.
Since the energy of the photon is inversely proportional to the frequency, does the frequency of the light change after it is reflected ?
Absolute statements are never true
But then the Loonies could revolt and use the rail gun to bomb the Earth!
I read a scientific article about it once.
I respond to your sigs
So let them build a space cable out to the Earth-Moon L1 point.
One line blog. I hear that they're called Twitters now.
The kinetic energy of the sail
initially: 1/2*m*v0^2
after some time: 1/2*m*v1^2
Since v1 > v0 and there is this thing called "conservation of energy", some extra energy is needed.
1. Patent soalr sails. 2. Wait for Technology to develope. 3. Lawsuite. 4. Profit.
"I helped my uncle Jack off a horse"
versus
"I helped my uncle jack off a horse"
I posted a question about using a giant rail-gun to ASSIST the use of SOLAR SAILS, the subject of the story.
How is that off-topic?
Yeesh.
Raise your children as if you were teaching them to raise your grandchildren, because you are.
The idea of rail-guns for launching vehicles came about because on other planets there wasn't enough atmosphere for aerodynamics to work or for jet engines to work. The relative vacuum and low gravity was an advantage for anything that didn't need to carry its own fuel. The rail gun would use electromagnetic fields to accelerate the vehicle to beyond escape velocity.
However, for Earth, you need a take off velocity of at least 7 miles/second (or 25,000 miles/hour). And that doesn't take into air friction. Assuming you could build such an aerodynamic capsule, you would need a considerable acceleration for a period of the launch phase.
To minimize the amount of energy you need to use, you'd want to travel straight up, and to generate enough energy you would probably have to burn gallons of hydrocarbons or run a whole chain of nuclear reactors. Since energy is most efficient when you use the least number of conversion stages, you really end up with a vertical rocket launch with solid or liquid fuel.
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
"Solar sails would thus be especially useful for journeys to distant planets or vastly more distant stars" But, as the distance from Sun increases, light intensity DECREASES as SQUARE of distance. When the sail reaches half way to another star, Sun will push it almost as much as that star (ok, a bit less because of difference in reflection).
But I asked about doing it from the Moon. Not much air friction there :-).
Raise your children as if you were teaching them to raise your grandchildren, because you are.
The shuttle blowing up didnt delay the ISS? comeon....
Any hoe, USA GOVT wont allow nasa to give any $$$ to russia so if russia hasnt got the cash what do you expect? The mafia to fund it?
OT: yes i know russia is spending billions in secret underground/mountain NORAD type cities with capacities for 50000+ people.
Which leads me to ask why any nation really 'prepares for ww3' and still economicaly deals with the enemy? -dont trust china-
Liberty freedom are no1, not dicks in suits.
If this is to "orbit" the earth it faces alot of challenges. Out atmosphere extends quite a distance to the moon. Sure it is atoms per cubic meter but it's appreceable . I suspect there will some frictional losses that will constrain the top end velocity. If it orbits that means that it has to go back around the other side, while the front surface is facing to the sun. Sure you can play tricks where maybe one side is reflective and the other approaches an ideal black body object and just absorbs. Or maybe when it is on it's orbit facing to the sun and while it is "tacking the wind" you retract the solar sail to reduce drag. Lots of challenges there to consider. You probably could get better performance if it had a highly elliptical orbit, in other words, more acceleration as it has the "wind in it's sails" and then when it reaches apogee you close the sails and let it accelerate back to earth using gravitational attraction. As this thing accelerates the orbit would become even more elliptical and as it does a swing by the earth (to go back into space) it faces frictional heating, geomagnetic forces where the electric charges on the instrumentation packages begin to wear on the electronics packages. Remember what happens when you move a piece of metal rapidly through a magnetic field, it induces voltages into the object being moved. It would be cooler, probably easier and more impressive if you sent it into deep space. Then when in mid course to another star, once it senses decelleration caused by the star it's heading to it would either close or eject the sail. Think of a solar sail built like a umbrella. Put the instrumentation package in the "handle" and also a microwave transmitter and feed horn. Face the feed horn right at the surface of the solar sail and this thing can do double duty as a giant microwave antenna (50-100 meters across). This would have a greater communication range than any deep space probe out there that are limited by the gain that their antennas can produce because of their relatively small size (a few meters across). Let's say you want to decellerate at the other end. Use a small thruster to turn the thing around mid-course and re-deploy the sail. The probe would slow down the closer it gets to the distant star. Possibilities, possibilities, my mind is awash.
Tisha Hayes
Give me something that goes 299 792 KM/s and we can talk then! :P
It's not the destination that matters, but rather the journey.
No, the point is that Russia has been funding its solar sail research, while being subsidized by the US in the ISS. Now the US is behind Russia in the more promising solar sail research, which we wouldn't be if we'd spent our subsidies on that instead. This doesn't require conspiracy theories - it's simple, obvious economics.
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100% Flamebait
TrollMods can't deny that Russia is having our cake and eating it too.
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Oh, the same way. At the destination since it would be in orbit around a distant star it could use it's sail (coated with a radio reflective material) as a radio-telescope and look for signs of civilization (assuming they use radio)or even some more esoteric means like looking for the water spectrum, oxygen etc... Then, it would reverse course, head back to earth (or some other star on a grand tour). I don't think this would really be a very efficient means of moving people. The acceleration would be in the hundreth or thousanth or ten thousanth of a G and would take many many years to even reach our nearest star. It's cool because it's a low energy and fairly low tech way of going places, if you have a long time to get there.
Tisha Hayes
Just make some long rails between few large bodies in our solar system. The rails would transfer the electricity to points right behind the train with electro magnetics and superconductors on the train would repulse it from the magnetic field. So there wouldn't be any mass for propulsion to move. As a superconductors inside rails would move the propulsion power to the ship.
;)
Sure, sure I definitely read the article
Emacs is good operating system, but it has one flaw: Its text editor could be better.
Did a little back of the spreadsheet calculation. If you take thr trhrust numbers fomr the article, you get a kilogram of thrust from every square kilometer. That's a millionth of a Kg from every square meter. Or a thousandth of a gram. If you assume the sail weighs .1 gram per square meter, that's an acceleration of 1/100th of a G. Not terribly impressive. Certainly not enough to push anything out of earth orbit. And a very slow way to tour the solar system. And what do you do at night? :)
Best Book on Solar Sails:c larke.htm#5484
http://www-users.cs.york.ac.uk/~susan/sf/books/c/
Arthur C. Clarke, editor. Project Solar Sail. Roc/Penguin. 1990
Contents:
Poul Anderson. Sunjammer. 1964
Arthur C. Clarke. The Wind From the Sun. 1963
Arthur C. Clarke. The Winds of Space (forward to Project Solar Sail). 1990
Isaac Asimov. Sailing the Void (introduction to Project Solar Sail). 1990
Ray Bradbury, Jonathan V. Post. To Sail Beyond the Sun (A Luminous Collage). 1990
K. Eric Drexler. The Canvas of Night. 1990
David Brin. Ice Pilot. 1990
Jonathan Eberhart. A Solar Privateer. 1981
Chauncey Uphoff, Jonathan V. Post. A Rebel Technology Comes Alive
Alfred Lord Tennyson. Argosies of Magic Sails
Brian Palaszewski. Ion Propulsion: The Solar Sail's Competition. 1990
Charles Sheffield. The Grand Tour. 1987
Scott E. Green. Lightsail. 1990
Kevin J. Anderson, Doug Beason. Rescue at L-5. 1990
Robert L. Forward, Joel Davis. Lightsails to the Stars. 1990
Joe Clifford Faust. Goodnight, Children. 1990
Robert L. Staehle, Louis Friedman. Solar Sails in an Interplanetary Economy. 1990
Arthur C. Clarke. Afterword to "Project Solar Sail". 1990
Larry Niven. The Fourth Profession. 1971
Their website says the acceleration is ~ .0005 m/s/s, which is 5/100,000 of a g (not a G), and the 'g' referred to here is not a gram, but the acceleration due to gravity at the Earth's surface, 9.8 m/s/s. That's very impressive, considering that acceleration could continue for as long as the sun keeps shining, which is more than enough time to lift something out of Earth orbit. Assuming the craft doesn't trade any kinetic for gravitational potential energy, it could speed up by 1600 m/s in a year (if I remember the number of seconds/year right- ~pi*10^7 s).
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
You've still got to get your launch rail transported and built, along with your power supply (nuclear reactor/solar panels). The launch rail would have to be anchored to the ground rock (if there is any) to make sure nothing works loose. And it would still have to project the vehicle up to at least 3600 miles/hour, which means it would have to be a few miles long. Using rockets is still the most efficient method.
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
Moderation -2
100% Flamebait
Which is the sacred cow here, TrollMods? Is it NASA, the ISS, the Shuttles, or Russia? Or are you so stupid that you're afraid I'm criticizing solar sails, or internationalized space research? Without any rebuttal, just anonymous TrollMod'ing, it's impossible to tell.
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