Online Journal of Space Communication


This paper offers a new space solar power reference design based on an elliptical 3-Hour sub-Molniya orbit. Most studies of space-based solar power (SBSP) systems to date have assumed that satellite stationing and photovoltaic (PV) solar energy conversion will take place in geostationary orbit (GEO). This paper argues that GEO/PV systems are not the most feasible solutions for SBSP, not technically and not economically.

Thirty six thousand kilometers above earth is a logical destination for a number of reasons, but that orbit is already largely committed. What is more, this great height and the mass and number of space solar systems proposed for GEO will not be cost-justifiable anytime soon. Decades will pass before this promising location will be a major solar power satellite (SPS) destination due to incumbent player resistance over possible signal interference. Also, dramatic improvements in space-based PV cell technology will be needed, as will reductions in the cost of space launch. SPS systems will be a predictable contributor to our energy future when these birds are built to operate in space at costs competitive with energy systems on Earth. Successful SPS designs will be those that are technically feasible, economically affordable and can be proven to work.

One way to shorten time-to-term, and thereby alleviate some of these constraints, will be to look for a workable non-GEO orbit. The author suggests a highly elliptic 3-hour orbit similar to the Molniya orbits used by the Soviets only operating much closer to Earth. This orbit will provide about 2 hours of transmission time per orbit and 1 hours of non-transmission time. When compared to the GEO location, this new class of sub-Molniya orbits has the potential to substantially reduce SSP satellite mass.



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