Light sail SPS; Sun-Earth L1 (was Correcting my own math -- CORRECTED)

On Feb 5, 2012, at 12:58 AM, Frank wrote:

> On 05.02.2012 01:36, Al Globus wrote:
> > Requires detailed engineering to answer. If you use solar electric,
> > the exhaust velocity is so high that you don't need much mass.
>
> I think, using your simulation you would have to make assumptions of
> the
> mass of a power sat. and the propulsion used.
>
I didn't do any propulsion. I just created a satellite with a mass of
100g/m^2 (actually, I tried various masses), put it in GEO and let it
go. Ran for one year to see how things went. Semi-major axis went
down a bit, eccentricity got pretty bad and there was some deviation
in inclination as well. However, the sat stayed in more-or-less
reasonable range of a ground station (it moved about, but beam
steering is possible).

The fact that the sat didn't really move around much suggests that one
can station keep without too much fuel, but I didn't quantify that.