Re: Recycling solar sails

From: Spike Jones (
Date: Fri Mar 23 2001 - 10:28:38 MST

Anders Sandberg wrote:

> While we all seem to be in space colonisation mode, what about
> re-using solar sail material?
> In my asteroid mining scheme, I send extra equipment using solar sails
> to the NEO mining base. So what do we do with them once at Orpheus; we
> can't have them litter the landscape.

It would be possible to keep them in a parking orbit by turning them
nearly edge on to the sun. Then the raw materials could be later used
for something else, if not a return trip to Earth.

> A solar sail would make a
> rather easily constructed solar oven when bent into a paraboloid and
> somehow anchored to the asteroid.

Or a reflector to direct sunlight down to the surface of the asteroid.
Sunlight being a scarce commodity out there, I could see where a
group of solar sails shining in the night sky would be a good thing
to have.

> They can also make a solar shade
> for the extracted fuel tanks during the trip back home to keep cooling
> of the hydrogen simple.

That sounds like the most reasonable use for them.

> (I guess they are not that useful for transporting propellant
> or other heavy products from the asteroid)?

No. The forces they provide are very small.

> Another use would be for the aerobraking part of the mission, where
> the fuel tanks are aerobraked for entry into LEO. The sails are
> definitely too flimsy to survive aerobraking in themselves, but I
> wonder if they might help provide some extra drag during the first
> pass. Any views on this?

I wouldnt think that would be a good use for them. An
aerobraking maneuver has all the *drag* it needs, simply
by plunging a little lower into the atmosphere. The limiting
factor there is the amount of heat dissipation the craft can
take. The little bit extra provided by (I assume you meant)
folding a sail over and over, then attaching to your ablative
shield would be too small to bother with perhaps. Theres
nothing stopping us from doing the calculations, however.

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