Interstellar travel [was Re: Recycling solar sails]

From: Robert J. Bradbury (
Date: Sun Mar 25 2001 - 07:39:43 MST

On Sun, 25 Mar 2001, zeb haradon wrote:

> If you are going on a one way trip, the sails will become useless at some
> distance away from the sun (or the lasers, as they disperse). If you're
> making a trip to another solar system, you could then reel the sails in,
> grind them up, and use them as propellant. This would dictate what type of
> material you can make the sails out of.

Zeb, I think the general strategy for interstellar trips should be to
take as little mass with you as possible. You want to use "matter
beams" driven by mass drivers to provide the fuel over long distances.
Lasers will spread out, but matter bonded together will not. You
could even ship alternating packages of matter and anti-matter.
You can provide sufficient on-board navigational intelligence
in the matter shipments to keep them targeted properly over
many parsecs of travel.

So much of the discussion of space travel has always focused on
the problem of taking your fuel with you, while constraining
yourself to accelerations that humans can tolerate. If you
split the problem so the humans accelerate at whatever velocity
they can tolerate and the fuel is accelerated to a velocity
such that when it reaches the ship it can provide momentum transfer,
but not at a velocity that exceed the heat dissipation capacity
of the spaceship that is the best strategy. Divide and conquer.

Of course this isn't 'solar sailing' so its off the topic that
Spike was dealing with.


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