Sailing

[Plane]

NASA researchers, thinking "out of the box" (or maybe "out of the rocket") have long dreamed of the possibility of sailing among the planets with sails propelled by sunlight instead of by wind. Except in works of fiction, though, no one has yet successfully deployed such a sail anywhere beyond Earth.

Right: An artist's concept of a sailing ship and a solar sail.

"There's a first time for everything," says Edward "Sandy" Montgomery of NASA's Marshall Space Flight Center.

Montgomery's team and a team from Ames Research Center (led by Elwood Agasid) hope to make history this summer by deploying a solar sail called NanoSail-D. It will travel to space onboard a SpaceX Falcon 1 rocket, scheduled for launch from Omelek Island in the Pacific Ocean during a window extending from July 29th to August 6th (a back-up window extends from August 29th to September 5th).


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"NanoSail-D will be the first fully deployed solar sail in space, and the first spacecraft to use solar pressure as a primary means of attitude control or orbital maneuvering," says Montgomery, who is NanoSail-D's payload manager.


http://science.nasa.gov/headlines/y2008/26jun_nanosaild.htm

[Michael Tee]

I remember this a long time ago in a science fiction story where the ships were propelled by an "ion wind," a rain of ions emanating from the sun.  This had to be in the 1950s.  Hope they find the author and name the first ship after him.  Or her.

[Xavier_Onassis]

In an episode of Star Trek DS9, Siskal and his son build a lightsail ship of I believe antique Bajoran design,  and take it for a spin.

There are a lot of wacko and unworkable concepts in SciFi, but lately there are more and more theoretically workable ideas.

[Amianthus]

I remember this a long time ago in a science fiction story where the ships were propelled by an "ion wind," a rain of ions emanating from the sun.  This had to be in the 1950s.  Hope they find the author and name the first ship after him.  Or her.

The concept was first proposed by German astronomer Johannes Kepler in the seventeenth century. It was again proposed by Friedrich Zander in the late 1920s and gradually refined over the decades. Recent serious interest in lightsails began with an article by engineer and science fiction author Robert L. Forward in 1984.

http://en.wikipedia.org/wiki/Solar_sail

[Xavier_Onassis]

In space there is no friction, so any impulse from any direction should result in acceleration in the opposite direction forever.

[Amianthus]

In space there is no friction, so any impulse from any direction should result in acceleration in the opposite direction forever.

There is friction in space, but it's very, very low. Even the hardest of vacuums has some particles present, this is how a Bussard ramjet works.

[Xavier_Onassis]

There is friction in space, but it's very, very low. Even the hardest of vacuums has some particles present, this is how a Bussard ramjet works.

By "no friction", I meant, "practically no friction".

No doubt by "works", you mean, "theoretically works".

I don't suppose that the tiny number of Hydrogen atoms in space would do much to slow down a solar sail powered craft.

[Plane]

At present the solar sail is the fastest spacecraft that we know how to make.

There are ideas for very fast spacecraft but none that don't require some more development.


If a cable is raised to stationary orbit , so that an elevator system makes freight to space cheap, then solar sails power ferrys to the planets , it is just barely conceiveable that the colinisation of the planets could commence in our lifetime , and be a going concern in the lives of our children.

[Xavier_Onassis]

At present the solar sail is the fastest spacecraft that we know how to make.


Since we have never actually made one that works yet, and do not know how fast they will go, I would say that the rockets we have are the fastest. Speed might approach half the speed of light, but acceleration might be rather slow.

Warp speed was a necessity for decent sci-fi, because igt is hard for the public to identify with an array of multi-generational Kirks, Spocks, McCoys and Scotties.
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The only spacecraft we have any experience with at all are rocket-powered.
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I would imagine that a rocket will be needed to get a spacecraft into space, then and only then will unfurling the sails be practical.

[Amianthus]

No doubt by "works", you mean, "theoretically works".

Well, ramjets have been made, just not ones that used fusion power.

[Xavier_Onassis]

Well, ramjets have been made, just not ones that used fusion power.

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Isn't fusion power being used for anything rather theoretical?

[Amianthus]

Isn't fusion power being used for anything rather theoretical?

Not really. We have a number of fusion bombs already. It's the control of fusion power that is difficult. At this point, once we touch off the reaction, it goes until it consumes all of it's fuel.

[Brassmask]

If I remember right, the speed from a solar sail increases over time.

[Amianthus]

If I remember right, the speed from a solar sail increases over time.

It's a constant acceleration, so speed must increase. Well, unless you turn it around, then the constant acceleration in the other direction will force your speed to decrease.

[sirs]

I'm still amazed that members of the starship enterprise never turn to liquid goo, in the rear of the ship, every time they go into warp.