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

On Feb 5, 2012, at 1:22 PM, Frank wrote:

> Am 05.02.2012 18:12, schrieb Al Globus:
>> I didn't do any propulsion. I just created a satellite with a mass
>> of
>> 100g/m2 (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).
>
> 100g/m2 would be around 80 tons for my reference design which would
> have
> about 30 tons of mass.
>
> Could you run your simulation for the 30 tons spacecraft with 37.5
> grams
> per m2 too? :-)

All that matter is mass/area. I've done sims at 50 g/m^2 and the
system gets blown all over the place. Doesn't work very well at all.
37.5 will just be worse. BTW: I used the STK (Satellite Toolkit) with
one of the propagators that includes light pressure, which you have to
pay for. You can, however, use the good propagator for 30 days for
free. So, make sure you have plenty of time, get the free STK and
sign up for the free 30 day trial and sim away.

My sim was a just a 1 m^2 satellite weighing 100 g (or 50, or whatever
I was interested in at the time).