From NEO to GEO --- an SPS scenario

Beaming energy directly from the NEO to Earth orbit is, I think, infeasible because of the huge, huge required size of the antenna/rectenna pair. The distance from GEO to Earth is 40,000km, and researchers have worked out the required sizes of the antenna/rectenna pair for that scenario, and they are already large at that distance. The distance from a NEO to GEO would be three orders of magnitude larger, and this fact would pump up the required antenna/rectenna sizes to ridiculous proportions.

Flying the SPS back from the NEO to GEO would be a better idea. The SPS is, of course, a huge power source. This power source can be used to drive some electrical propulsion system. Some electrical propulsion system will be needed anyway in order to do station-keeping in GEO, so it is already required to know how the SPS will respond to propulsive inputs. Having the electical propulsion system move the SPS back from the NEO to GEO is merely an extension of the technology that will be required for station-keeping anyway.

Ron Menich

"Tom Musgrove"
07/05/2001 04:52 PM

Depends on whether the NEO is closer or further from the sun than the earth
is.

Since the radiation intensity decreases with the inverse square of the
distance, further away means less energy/m^2.

Also, rectennas would have to absorb and retransmit, so a reflector that
reconcentrates the beam would be preferable.

Additionally, the distance from the NEO to HEO is likely to be further than
say, the moon to HEO, so the size of the rectenna/reflector would have to be
much larger and hence more expensive...

Tom M.
TomM@...