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  (Source: NerdModo)

The Sagan-inspired LightSail-1 will launch next year aboard a Russian or American rocket.  (Source: Rick Sternbach/Planetary Society)

The solar sail will unfold once in orbit and hopefully catch the sun's light, helping it to acclerate.  (Source: Frank O'Connell/The New York Times)
Design may be suitable for carrying probes to the stars

The problem of making space travel more efficient is a complex one.  First there's the challenge of getting materials cheaply into orbit.  Space elevators are currently viewed as perhaps the most promising solution for this.  Then there's the challenge of developing sufficient impulse and thrust to push probes or spacecraft to the stars.  For this challenge everything from plasma, to ion, to nuclear engines have been dreamed up.

Joining the various in-space alternative propulsion technologies to be tested in the near future is a relatively old idea -- the solar sail.  Next year the Planetary Society, a space research group, and Cosmos Studios of Ithaca, N.Y., headed by Ann Druyan, a film producer and widow of the late astronomer and author Carl Sagan, will launch LightSail-1, a solar sail design. 

Louis Friedman, Ph.D, director of the Planetary Society, brags, "Sailing on light is the only technology that can someday take us to the stars."

The solar sail was embraced by late writer Carl Sagan, and now is championed by his widow.  The concept is simple -- absorb the energy from incoming light and cosmic rays and use it to accelerate the spacecraft, much like wind on an ocean sail.  A solar sail's ability to constantly draw on solar energy for thrust enables it to, in theory, traverse the solar system in 5 years -- a feat likely not possible with other engine designs.  With a concentrated laser, a 100 year trip to another solar system might be possible, allowing humans to potentially explore another solar system for the first time.

Currently radiation on such a trip would be prohibitive and would likely kill any humans that went solar sailing.  Weight restrictions also would make such a long trip hard to manage -- the more weight you want to transport, the bigger the sail you need.

Both NASA and Japan's space agency, JAXA, have developed and tested solar sails, but thus far no one has tried to sail them anywhere.  The collaboration between the Planetary Society and Cosmos Studios aims to be the first to do that, launching a series of solar sails over the next few years.  It looks to first prove the technology, then launch a sail into deep space.

The group first tried to launch as solar sail called Cosmos-1 back in 2005.  Approximately 100-feet per side, the square sail was launched from a Russian missile submarine in June 2005, but the launch failed, leaving the sail at the bottom of the Barents Sea.

Undeterred the team turned to a NASA contract for funding, developing a smaller 18-foot-per-side Nanosail, which could be used to deorbit satellites.  They took that design and used it as a basis for the new LightSail-1. 

The LightSail-1 features an aluminized Mylar sail, about a quarter as thick as a trash bag.  The sail will carry three 4 in. x 4 in. x 4 in. CubeSats, tiny electronics boxes developed by students at Stanford.  Two of the boxes hold the sails, before they are stretched, while the third will contain the electronics to control positioning of the sails.  By positioning the sails to balance gravity with the force from solar energy, the spacecraft will be able to perform complex maneuvers like braking or hovering in place.  The system will weigh a scant 5 kg to make the most of the small sail area.

The groups are looking to piggyback the design on an American or Russian rocket launch carrying another satellite.  This should be possible thanks to the small size.

The first planned flight will simply send the sail into orbit and hopes to spot signs of acceleration via a built in camera.  The team describes this as their "Kitty Hawk moment", referring to the famous Wright brothers flight.  The next flight will involve a larger sail, which will orbit for several days building enough acceleration to raise its orbit tens or hundreds of miles. 

A third flight will look to send a sail out of Earth's orbit, attempting to place it at the L1 point, about 900,000 miles from the Earth, where the solar gravity will be balanced by the force from light energy on the sail, causing the sail to stall in place, orbiting the sun.  This most ambitious objective will likely require a small chemical rocket to provide the extra power needed to escape orbit, something that may frustrate fans of the design, admits Dr. Friedman.

However, Mr. Friedman likens the chemical rocket to the motor that is typically needed to get sailboats out of the harbor and onto the open sea.  He says that once the Earth's gravity well is escaped, the sail can take over.  If the team can achieve its goal, the positioned satellite will then be used to watch the sun's activity for magnetic storms that could damage spacecraft or on-Earth electronics.


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pirates
By SonicIce on 11/13/2009 12:02:18 PM , Rating: 3
We're already paving the way for space pirates. Ahoy! We're boarding your ship. Asteroid ho!




RE: pirates
By Cr0nJ0b on 11/13/2009 12:37:49 PM , Rating: 5
I think we're safe, at least until Somalia's space programs takes off.


RE: pirates
By quiksilvr on 11/13/2009 12:44:57 PM , Rating: 2
Don't hold your breath.


RE: pirates
By amanojaku on 11/13/2009 12:56:42 PM , Rating: 2
The solution is space sharks. With lasers. The only booty those pirates will see is the moon! ;-)


RE: pirates
By stirfry213 on 11/13/2009 1:33:49 PM , Rating: 2
You're close, but its not the Somalian's we have to worry about. Its the Sariens and their dirty, no good, worthless leader Vohaul. They are the real enemy here.

Where is Roger when you need him?


RE: pirates
By JediJeb on 11/13/2009 4:08:28 PM , Rating: 2
Just hope you are not transporting any ice, or the Ice Pirates will get you.


RE: pirates
By foolsgambit11 on 11/13/2009 6:04:04 PM , Rating: 2
Nice. Equally old school, I'm worried the space pirates will come and steal all my crystite (or smithore, depending on difficulty level).


RE: pirates
By Motoman on 11/16/2009 2:32:59 PM , Rating: 2
Watch out for the space herpe!


RE: pirates
By lainofthewired on 11/13/2009 12:49:17 PM , Rating: 3
I can almost see the Jolly Roger stuck to a corner of those sails.

"Louis Friedman...brags, 'Sailing on light is the only technology that can someday take us to the stars.'"

Seems a little presumptuous to me there, buddy. Maybe the only current technology...


RE: pirates
By Master Kenobi (blog) on 11/13/2009 1:31:00 PM , Rating: 3
Ion and more so Nuclear (Or a combination of the two) will easily provide interplanetary capabilities, if not interstellar.


RE: pirates
By randomly on 11/14/2009 9:10:05 AM , Rating: 3
Ion is a thruster technology, it won't go anywhere without a power source. None of the current Ion design concepts have a high enough exhaust velocity for interstellar travel.

Nuclear thermal rockets are limited to exhaust velocity of 10,000 m/sec. This is about twice what the Shuttle engines do. You can improve this by a factor of 1.5-2 if a gas core reactor design can be realized. but this is still insufficient for interstellar travel.

For interstellar travel you will need some type of fusion drive or beamed energy propulsion to achieve sufficient speed to get to a nearby star in less than a thousand years.

Interplanetary travel is another matter. A high power nuclear reactor providing electrical power to an ion thruster such as the VASIMR would get you to anywhere inside the orbit of Jupiter before you got a fatal dose of radiation from the Galactic Cosmic Ray background, something our current chemical rockets can't do.

Unfortunately until somebody builds a high power space capable nuclear reactor to power an Ion drive it will be difficult for humans to get out of the inner solar system.


RE: pirates
By mezman on 11/16/2009 2:59:52 PM , Rating: 2
I am NOT an "Asteroid ho!"


I dont think so...
By freeagle on 11/13/2009 3:17:39 PM , Rating: 2
quote:
Louis Friedman, Ph.D, director of the Planetary Society, brags, "Sailing on light is the only technology that can someday take us to the stars."


Without help of a laser, it wont get near stars with higher light output than sun. The light from these stars would stop it and send it back where it came from before the sail could enter the solar system. This is not a problem with stars that have <= light output.

With the help of a laser, the gained speed would be so high it would just pass through the solar system very quickly, with no real way to slow down. Not to mention the fact that should one need to alter the laser intensity, he'd have to think about this a few years before the change would have any effect on the sail.

I'm not saying sails are useless, but saying they are the
quote:
only technology that can someday take us to the stars
is dumb at the very least.




RE: I dont think so...
By Randomblame on 11/13/2009 4:11:34 PM , Rating: 2
the laser is used to add acceleration beyond the inner range of our solar system, the sails would only cause deceleration upon reaching the inner range of another solar system - which would be very useful for actually entering orbit of that particular star.

The planned project is made up of 3 different sails:
the first for low earth orbit
the second for high earth orbit

the third is planned to reach a lagrange point to evaluate a design as a solar weather outpost, due to it's sails it can find equilibrium far closer to the sun than a traditional satellite and give us more advanced warning of solar flares with the potential to disrupt communications, power grids etc.

"How could it stay closer to the sun though with solar sails pushing it away" - a question I'm sure someone will ask

A Lagrange point is a region of gravitational equilibrium between two planetary bodies in this case the earth and the sun. The solar sail could stay closer to the sun than traditional satellites because the pressure from the light will help to counter the larger gravitational pull from the sun.

quote:
quote: only technology that can someday take us to the stars is dumb at the very least.


You are dumb at the very least.
Using a traditional chemical rocket to get us quickly to another solar system would necessitate a MASSIVE vehicle, with 80% of it being fuel and fuel containment which adds a considerable inefficiency as that fuel burns and the weight of the container does not. With a solar sail the propulsion, and energy storage Necessary for propulsion does not have to be moved itself, it can stay at L1 in the form of a large solar powered tightly focused laser and transmit it's energy to the sail. That means more room for food, and less mass for faster travel.

A large chemical rocket would also have to be very carefully controlled on acceleration - to prevent gforces from damaging the structure of the vehicle and/or killing it's occupants. A solar sail provides gradual constant thrust.

I'm not saying it's perfect by any means, I'm saying that it is the best technology for this purpose that we currently have at our disposal and possibly the best we will ever have. Louis Friedman has a Ph.D, where is yours?


RE: I dont think so...
By cochy on 11/13/2009 4:27:47 PM , Rating: 2
He didn't say that the solar sail was a dumb idea only that saying it's the only technology available for inter-stellar travel is a dumb statement.


RE: I dont think so...
By freeagle on 11/13/2009 5:15:51 PM , Rating: 2
The first half of your post doesnt reply to anything i've written.

If you use laser for propulsion, how are you going to decelerate? There is not a laser in the targeted solar system to slow you down, and it's star would not be enough. Not to mention, again, there is no reasonably quick way to control the thrust as the sail gets further away. Your decision to increase/decrease the power of the laser would make effect on the sail 2 years after you decided to do so ( assuming the sail is half the way to alpha centauri )

I did not propose to use traditional chemical propulsion systems for the task. I didn't even hint at it. Disadvantages of these systems are well know to me for this type of project. Ion, plasma and the likes on the other hand...

quote:
I'm not saying it's perfect

That means there is or will be a better alternative. You are contradicting yourself:
quote:
it is the best technology for this purpose that we currently have at our disposal and possibly the best we will ever have.


quote:
Louis Friedman has a Ph.D, where is yours?

So I'm not entitled to objection if I dont have one?


RE: I dont think so...
By psychmike on 11/13/2009 9:25:48 PM , Rating: 2
You raise important questions.

Some people have given thought to deceleration. There is one model in which part of the sail detaches and continues to accelerate away from Earth while reflecting the laser from Earth back onto the ship causing deceleration.

Perhaps you disagree with the way in which Dr. Friedman expressed his view, but if you absolutely had to send something into deep, deep space, there is no better technology in the foreseeable future than solar sails. There are certainly options that might become viable in the future but his statement (at least in my opinion) is accurate at this point in history.

Given the vast distances involved, a gentle, continuous push is far more effective that a massive brief push and there have not been any realistic models in which that continuous push can be generated internally by the ship. Various forms of ion propulsion seem like candidates but the high amount of energy that would have to be produced on the ship, the enormous amount of mass needed for fuel, the accelerator corrosion, and the extremely high cost of ideal fuels suggest that this technology is currently better suited for intrasolar system exploration.


RE: I dont think so...
By freeagle on 11/14/2009 9:47:27 AM , Rating: 2
Maybe I have misunderstood what he meant exactly by his statement, but it did give me an impression he thinks there will never be anything better. I can not agree with this.

I agree that it might be one of the options from currently available technologies. Maybe even the best. It's not my place to decide that


RE: I dont think so...
By psychmike on 11/14/2009 10:38:33 AM , Rating: 2
You're right, of course. People (including scientists) have a long history of saying that something is impossible only to find a few years later that they were wrong (e.g., manned flight, breaking the sound barriers, etc.).

At the same time, scientists are trained to think and speak a little differently from others. Saying that 'another techology might come along some day' is a bit of an unprovable argument. How would you ever know if you were wrong? If nothing comes along in the next 10 years, something could still come along in the next 100, 1,000 or 10,000. Far be it for me to put words in the good doctor's mouth, but I believe that what he was saying is a lot more circumscribed. He seemed to be saying that there is no other viable option that exists or that is currently forseeable. To me, he didn't seem to be making a prediction about the future ('some day' seemed to be about the implementation of the technology) but about the general present.

Best,
Michael


RE: I dont think so...
By SPOOFE on 11/13/2009 9:51:27 PM , Rating: 2
His comment is even more ignorant than that; he's ignoring the prospects of nuclear pulse propulsion, also known as Project Orion back in the '50s. In the day, it was tossed about as an idea for lifting loads off the ground, but the nuclear detonations made that a very unattractive idea. Using NPP once already in space, however, has numerous advantages: The larger you scale the design the more efficient it gets (try that with solar sales), and as a result you could build the thing out of common steel and concrete. Further, it gives you the size necessary for a proper colonization vessel. And using some thousands of nuclear warheads can get your vessel up to around 10 percent the speed of light, not at all an unrealistic acceleration to travel to the stars.

Sure, it's not right around the corner, and one still has to tackle the problem of getting enough material in orbit is a problem, but nobody's claiming that we'll start Star Trekking next week.


RE: I dont think so...
By kattanna on 11/16/2009 10:39:22 AM , Rating: 2
quote:
I'm not saying sails are useless, but saying they are the

only technology that can someday take us to the stars

is dumb at the very least.


and since not a single one has even been tested in space, i couldnt agree more.

once they get a working one tested out in space, no not LEO, but actual deep space going somewhere, then that statement might have some validity.


1/5000th of an inch eh?
By Silverel on 11/13/2009 12:56:24 PM , Rating: 2
That thing is going to get ripped to shreds as soon as a little bit of space junk hits it... lol




RE: 1/5000th of an inch eh?
By jaericho on 11/13/2009 2:08:05 PM , Rating: 2
What about Magnetic sails. I always thought that was a neat idea. http://en.wikipedia.org/wiki/Magnetic_sail It's similar to a solar sail but no large, super thin sails to get shredded.


Huh?
By bhieb on 11/13/2009 1:55:53 PM , Rating: 2
quote:
With a concentrated laser, a 100 year trip to another solar system might be possible


Please correct me if I'm wrong (and I probably am), but I did not think this was possible (at least not with an onboard laser). Any energy gain from the laser light hitting the sails would be offset by the reverse thrust caused by "throwing" the beam out.

Also if your going to carry fuel to power the laser, why not just power an ion/plasma engine instead as they will not loose power as you get farther away from the sun.




RE: Huh?
By Etsp on 11/13/2009 2:00:27 PM , Rating: 2
Well, maybe they're thinking something along the lines of what's detailed in this article: http://www.dailytech.com/Scientists+Laser+Engine+M...

Rather than have the laser be onboard, it would be on the earth(or moon) and constantly shoot at it whenever it has line of sight.


Great Idea not.
By SuckRaven on 11/13/2009 1:56:56 PM , Rating: 2
quote:
We want to land a craft, deploy solar sails. You'll have a great big canopy. Solar winds will be caught by these Mylar sails!


Does this bright idea remind anyone else of one of those highly caffeinated astrophysicists in the movie Armageddon, when they are all sitting around thinking up ways in which to land on the surface of the asteroid?

LMAO




RE: Great Idea not.
By AstroGuardian on 11/17/2009 5:57:40 AM , Rating: 2
Yea, the whole idea is stupid. It won't work


this is why
By Randomblame on 11/13/2009 3:51:44 PM , Rating: 3
this is why I'm a member of the planetary society, for 20 bucks a year you get to support projects like this one, you get a subscription to their magazine and a bunch of other cool things. - plus it's a tax write off so why not do it?

www.planetary.org




Old news
By jebo on 11/13/2009 1:17:11 PM , Rating: 2
Captain (or was it Commander?) Sisko did this back in what, 1998, using a Bajoran design.

Wake me up when we're making real progress.




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