Space Forum / Space Flight / September 2003

I need help in calculating the gravitational drift at L1, 30,000+ km above
lunar near side.

I'm curious how much stationkeeping fuel, per period of time, a SPS located
there would require, per ton of SPS mass, with an ISP of 369. Something like
a reboost for 20 seconds duration, every 30 days, for every 10 tons of SPS.

For the simplicity sake I'm assuming NEO derived Methane with minimal
processing in orbit, and lunar derived LOX.

I'm trying to avoid the deep cryogenic temperature of LH2, and the extensive
orbital refining that'll be required for UDMH, hydrazine, nitric acid, and
other hypergolics.

I realize solar electric ion would make a lot of sense, but getting the gas
will involve Earth launch and I'm already assuming some NEO volitile
traffic, so getting the Methane isn't a sole purpose mission.

I've considered lunar derived aluminum and LOX but I'm not too confident in
the performance of this combination.

I'm also avoiding silane because I"m looking to have as simple an
infrastructure dedicated to fuel production. The LOX is produced through the
ilmenite reduction process. Hopefully, raw methane from NEO, with minimal
processing, does the trick.

Lastly, I don't know enough about a lunar sulphur and LOX combination, so
I've excluded it from consideration at this time.

Can anyone help with some realistic numbers?

TangoMan