Jamie Davison wrote:
> Erm, Solar sails aren't really massively steerable, unless you can find
> another source of light pressure to fly away from.

The transfer of momentum to/from a reflected photon, and thus the force
of light-pressure on the sail, is perpendicular to the sail.  You steer
by changing the angle of the sail to the sun.

For maximum efficiency, i guess the sail needs to be flat.

-- 
Anton Sherwood  --  br0### [at] p0b0xcom  --  http://ogre.nu/

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Ken wrote:
> A few years ago Arthur C. Clark wrote a book on the subject. One of
> the articles mentioned intersteller travel using solars sails with
> the assitance of space based sun driven laser systems. The speculation
> was that it is possible to not only drive a craft to a nearby star
> with a laser but it is also possible to return it with the same
> system. You can use tacking (just like in sailing against the wind)
> for the return trip. It would naturaly take longer to return but
> it is technically feasable.

Against the `wind' *and* against the gravity of the star at the other
end?

In Robert Forward's _The Flight of the Dragonfly_ / _Rocheworld_, the
ship jettisons part of its sail when it approaches the target, and uses
light reflected from that part to brake.

-- 
Anton Sherwood  --  br0### [at] p0b0xcom  --  http://ogre.nu/

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