New age of sail

I've been thinking for a while about the proposed use of solar sails for space exploration. (sadly, the last attempt went up on a failed rocket)

From my extremely limited knowledge of nautical sailing, it seems that for movement, you only really need 2 different mediums to apply force to a vessel. Wind, and some kind of stable refrence. On an ocean, the second force is the hull of the ship against the water, in space, it could be gravity. So it seems that if someone really wanted to make a solar-sail boat, the forces neccisaryare in place.

Where this becomes relevent is when one considers economical travel between planets. (IE: colonies) With a large enough sail, you could in theory travel almost anywhere in the solar system. (Okay, there would be practicle limits of too close and too far from the sun) More importantly, you could do so without having to drag along and expend fuel for propolsion all along the way. I'll grant however, that other craft would be neccisary, as solar sails will not lift you into planetary orbit, or easily escape that orbit. perhaps a form of orbital docking stations would become neccisary.

So what is everyone else's opinion? Could attempts at extra-planetary colonisation lead to a new age of sail? And if so, would the sudden availability of practicle craft usher in a new era of massive exploration of every planet and moon within reach? (leading of course to further refinement of 'sailing' vessels)

[edit on 11-1-2006 by Travellar]

What kind of speeds could you expect from such an arrangement?

And would there be any stopping ability available?

I'm not thinking so much of a slamming on the brakes deal, more of a bleeding off of speed if you find yourself on a collision course with a rock, asteroid or the like.

Would the craft be able to sail "against the wind"?

I'm assuming for practicle useage, you'd need the ability to manipulate your sail area, and aspect angle. So changing coursse, or even slowing down while on the way really just consist of shifting the sails.

As for "sailing against the wind", that's a really easy thing to accomplish. just pull the sail in and fall towards the sun.

Solar Sails show more promise in the form of being a good transport from one solar system to another...Not for close use like the moon or Mars.
As for light...On a mission that heads far out away from the sun, it could use an on board laser to keep increasing its speed.

It could still prove to be cheap and feasable for KBO's.

The sail is puched by light (photons), which bounce off the reflective sail to gently puch the craft, but the force they exert is very very small, It would take awhile to gain the nessesary speed. I would assume for any mission it would use the suns gravitational pull by getting pretty close to it and keep gaining speed, until you have enough speed to stop circleing it and head towards your destination. Its theorized that Solar Sails have the potential to go 1/10 the speed of light.

[edit on 11-1-2006 by Murcielago]

Solar sails get thier main thrust by solar particales from the sun. anotehr idea is to use very high powered lasers to provide extra thrust.

Modern day sail ships use the wind as a propellent, and even in a limited extend the Bernoulli effect. not really the best comparisons except that both solar sails, and wind sails, require no propellent or engine

ESA have been proposing the use of solar sails for some time now, first I heard of it was 2003, but I assume it had been going on for some time before that again.

sci.esa.int...

Originally posted by Travellar
I've been thinking for a while about the proposed use of solar sails for space exploration. (sadly, the last attempt went up on a failed rocket)

From my extremely limited knowledge of nautical sailing, it seems that for movement, you only really need 2 different mediums to apply force to a vessel. Wind, and some kind of stable refrence. On an ocean, the second force is the hull of the ship against the water, in space, it could be gravity. So it seems that if someone really wanted to make a solar-sail boat, the forces neccisaryare in place.

Where this becomes relevent is when one considers economical travel between planets. (IE: colonies) With a large enough sail, you could in theory travel almost anywhere in the solar system. (Okay, there would be practicle limits of too close and too far from the sun) More importantly, you could do so without having to drag along and expend fuel for propolsion all along the way. I'll grant however, that other craft would be neccisary, as solar sails will not lift you into planetary orbit, or easily escape that orbit. perhaps a form of orbital docking stations would become neccisary.

So what is everyone else's opinion? Could attempts at extra-planetary colonisation lead to a new age of sail? And if so, would the sudden availability of practicle craft usher in a new era of massive exploration of every planet and moon within reach? (leading of course to further refinement of 'sailing' vessels)

[edit on 11-1-2006 by Travellar]

There is more to consider here. The fact that space is not empty. To use the ocean sailing analogy, you'd be sailing an ocean of reefs. You'd have to have some kind of "force field" to protect both the sail and the vessel.

Nasa is also studying them, in hopes to launch the first interstellar spacecraft by 2010.
If launched in 2010, it could pass Voyager 1, which is the furthest away from us, launched back it 1977, the Solar Sail would pass this craft by 2018...meaning what took the voyager 41 years to reach, only took it 8 years!

Interesting that they seem to rely on booms to hold it's shape. I was imagining something more like a parachute. Only curved to more of an equalateral triangle, with a total of 6 lines running to it. (one for each corner, one for each midsection) That way, you could 'trim' the sail by pulling in the different lines, and even adjust how much thrust you recieve by using the mid-section lines to 'dump' your chute.

I've read about nanostructures holding the sails together, which have the ability to change shape, for the sail to manoeuvre and to slow down. I think there was a thread posted a while ago about space probes which talked about it.

Originally posted by Travellar
Interesting that they seem to rely on booms to hold it's shape. I was imagining something more like a parachute. Only curved to more of an equalateral triangle, with a total of 6 lines running to it. (one for each corner, one for each midsection) That way, you could 'trim' the sail by pulling in the different lines, and even adjust how much thrust you recieve by using the mid-section lines to 'dump' your chute.

They are very different from parachutes. They just get related to them a lot so the average joe schmoe can have a very limited idea of how they operate.

as for the booms...I've seen some that are designed to be inflated apon arrival to space...either by oxygen or some other type of gas.

I'd still liek to see them in greater use, as it still seems to be the most fuel efficient means we currently have the tech for to get from place to place. well, that, and Ion engines.

Unfortunately, I don't believe either propulsion is currently capable of lifting a craft away from a nearby planet it's orbitting. So you still need to drag along some rocket fuel.

Originally posted by Travellar
I'd still like to see them in greater use, as it still seems to be the most fuel efficient means we currently have the tech for to get from place to place. well, that, and Ion engines.

Unfortunately, I don't believe either propulsion is currently capable of lifting a craft away from a nearby planet it's orbiting. So you still need to drag along some rocket fuel.

Solar sails I dont think are very good for solar system use...since they take so long to get up to speed...but who knows...in the future they might be, by making them go faster quicker with the help of lasers or microwaves.

As for Ion engines...They aren’t just a concept, and couple different spacecraft have used them, the most current being ESA's moon probe called SMART-1.
And they are powerful enough to escape the gravity or in orbit around a planet (or moon), Hence the concept JIMO, which was a nuclear powered spacecraft that would get into orbit around 3 different moons, and have enough power to go into orbit, stay there awhile, and then leave when your done taking pics and other tests, and go to the next Jupiter moon on the list. I dont know its current status...last I knew Nasa cancelled it cause they wanted a mission before is to help test all of the equipment that would be needed for a mission of that magnitude.

Edit: I did some looking on the Ion engines, and Although JIMO has been cancelled, its not the only mission that Nasa had planned to use an ion thruster. Dawn, Is the name of a probe that will orbit 2 asteroids...a couple of the largest asteroids we know of. But unfortunatly Nasa has put Dawn on a stand-still, last November because of budget issues...it was scheduled for a mid-06 launch...I'm not sure what it is at now, but luckily for the Dawn team, they have a 1 year launch window, so the delay of launch could last until mid-07 and still be able to do its mission.
The Jimo replacement, is called Juno, and should launch in 2010, and will orbit Jupiter.

[edit on 17-1-2006 by Murcielago]

Can these solar sail craft fly a hull?

If a laser is to be used, where do you folks assume the emmition source would have to be located? How far out past Earth would this aperatus have to be or can this propulsion technique be accomplished from Earth orbit? How difficult is it going to be aiming that laser at a craft constantly becoming smaller in view and constantly being bombarded by the forces of our solar system and beyond? ie, gravity, clouds of gas, planets and other objects seeping in the way of the beam