NASA to Launch Solar Sail

arbitraryaardvark writes "Physorg reports that NASA will launch a solar sail around the end of July. It'll be the first of its kind; a previous attempt blew up. It's a small proof-of-concept gizmo, not a full-on spaceyacht. Solar sails operate on photon pressure from sunlight. They are well known to science fiction readers, otherwise not so much." C-net has coverage, too.

Comments

Beating against the solar wind?

[DerMatsi]

From TFA: "And like a marine sail, a solar sail could also bring you home. You could use the solar sail to tack your vessel, making it travel "against the wind," back to Earth." I don't see how this would be possible.. sailboats can do this because of a keel which exerts force on the water, which cannot be done in the near vacuum of space. Or am i missing something?

Re:Beating against the solar wind?

[techno-vampire]

AIUI, wearing and tacking are two separate ways to change course across the wind. In tacking, you turn your ship across the wind, using the ship's momentum to keep you going until your sails can catch the wind. (If you fail, your ship is said to be "in irons," pointing directly into the wind with no forward motion.) Wearing ship is much easier but, as you note, takes more room. You turn away from the wind going all the way around in a big turn and emd up with the wind on the other side of your ship. Although it's slower, it does have the advantage of avoiding any chance of getting stuck.

Rail Sail

[Doc Ruby]

I'd like to see a maglev train on an Andean mountain firing a ship into Earth orbit, which then deploys solar sails to catch the much more plentiful direct solar radiation to accelerate it away from the Earth. That seems like a better way to use the infrastructure we have on Earth, where at least 25-30% of the solar power is lost in the atmosphere and the air creates drag on the accelerated ship, and to use the microgravity and vacuum of space where it's easier to deploy light, flimsy solar collectors in the full sunlight.

Re:Ah, sigh

[Plazmid]

What do you mean? Wood has strength to weight ratio similar to that of carbon fiber, however wood is much cheap than carbon fiber. The main reason wood isn't used to build spacecraft is that wood is porous, but this might be solved by vacuum coating the wood with aluminum.

Re:I wonder...

[Orange Crush]

A solar sail craft's maximum speed will be considerably less than c. Mass-to-sail ratio and diminishing radiation pressure as the craft travels further from its star will be the biggest limiting factors.

Re:Ah, sigh

[ricegf]

In the book "The Trouble with Tribbles", David Gerrold mentioned that an early Star Trek script included three pages of technically accurate dialog between the Good Captain and his crew to get the Enterprise turned to head to the newest monster-of-the-week. Gene Roddenberry scratched out all three pages and replaced it with a single Captain Kirk command: "Turn around!"

Re:Ah, sigh

[CrimsonAvenger]

Solar sails are nothing but gossamer (light weight) sails. If it was that easy to get something like that to generate electricity with something as thin as standard garbage-bag plastic I'm sure we would have done it before. Solar panels are pretty much a similar process related to CPU/microchip fab == silicon chip == expensive and heavy.

Every time I read something like this ("but that's impossible!"), I think about 1900. Amazing the number of things that were "impossible" in 1900 that we do routinely now....