Designs for geostationary SPS are extremely large in scale, more than an order of magnitude larger than
the International Space Station. The problem of how to control the orbital motion of such large structures,
accounting for various perturbing forces, is therefore a topic worthy of further study. The primary objective
of the proposed research is to perform a detailed study of SPS orbit dynamics, obtaining a comprehensive
understanding of the effect of perturbations on orbits of large SPS structures over a time-frame commensurate
with proposed SPS lifetimes (30-40 years). Analytical equations derived by the process of averaging of the
SPS equations of motion shall be used in determining the long-term orbital behaviour. Previous studies have
simply assumed a geostationary orbit (GEO) then designed control systems for maintaining it thus. It is
found that an alternative SPS orbital location known as the geosynchronous Laplace plane (GLP) is superior
to GEO. An SPS in GLP requires virtually no fuel to maintain its orbit, avoids the main orbital debris
population originating from GEO satellites and is extremely robust, i.e. loss of control is inconsequential.
The GLP SPS saves of order 10<sup>4</sup> to 10<sup>5</sup> kg per year in fuel compared to a GEO SPS for equivalent power
delivery compared to GEO
