This is the final report of a two-year assessment of magnetospheric effects of the construction of an SPS at LEO. The operational activities of the SPS and a major segment of the constructional activities take place in the magnetosphere, which is a region of near-earth space where the ionized medium is controlled by magnetic and electric fields. These activities in space represent a loading upon the tenuous but spatially vast magnetospheric environment. The magnitude of this loading, in the form of injections of matter and energy, can be qualitatively accentuated by comparison of the mass of the SPS spacecraft at GEO with the largest spacecraft operated to date [Skylab] at LEO. While Skylab did not seem to have any appreciable effects upon the magnetosphere, the key question is whether the scaling-up of spacecraft mass by three orders of magnitude and the scaling-up of orbit altitude by two orders of magnitude would have appreciable magnetospheric effects.