0191 -9067/80/040269-11 $02.00/0 Copyright ® 1980 SUN SAT Energy Council CHANGES IN THE TERRESTRIAL ATMOSPHERE-IONOSPHERE-MAGNETOSPHERE SYSTEM DUE TO ION PROPULSION FOR SOLAR POWER SATELLITE PLACEMENT S. A. CURTIS and J. M. GREBOWSKY Laboratory for Planetary Atmospheres NASA/Goddard Space Flight Center Abstract — In order to construct Solar Power Satellites using earth-based materials, sections of a satellite must be lilted from low earth to geosynchronous orbit. The most plausible method of accomplishing this task is by means of ion propulsion based on the relatively abundant terrestrial atmospheric component, Ar. The proposed propulsion system will release a dense beam of ~5 keV Ar* (1). The total amount of Ar* injected in transporting the components for each Solar Power Satellite is comparable to the total ion content of the ionosphere-plasmasphere system while the total energy injected is larger than that of this system. We give preliminary estimates of the effects massive Ar* injections have on the ionosphere-plasmasphere system with specific emphasis on potential communications disruptions. The effects stem from direct Ar’ precipitation into the atmosphere and from Ar* beam induced precipitation of MeV radiation belt protons. It is suggested that should more detailed studies find the environmental modifications intolerable, the use of lunar-based rather than earth-based satellite construction materials should be considered. 1. INTRODUCTION We wish to examine the possible environmental impacts of one aspect of Solar Power Satellite (SPS) construction involving the lifting of SPS components from low earth orbit to geosynchronous earth orbit using orbital transfer vehicles powered by solar arrays. In current studies, this is the second stage of a two-step process envisioned when terrestrial materials are used in SPS construction (1). The first step is lifting materials from the earth’s surface to low earth orbit with a heavy lift launch vehicle which is planned to be an enlarged later generation of the current Space Shuttle. In the second step, orbital transfer vehicles will inject ~2 x IO6 kg of ~5 keV argon ions into the near earth environment in the process of carrying the components that will comprise the £10* kg SPS (2) from low earth orbit to geosynchronous earth orbit. The physics of this Ar+ beam has been studied in detail by Curtis and Grebowsky (3). They show that only a small fraction of the total mass of the Ar+ beams emitted by the orbital transfer vehicles is stopped in the plasmasphere. We note that another preliminary study (4) has tentatively concluded that all of the Ar+ beam is stopped in the plasmasphere. However, even if only a fraction of the beam is stopped, this fraction represents a very large injection of energetic ions relative to the naturally occurring plasmasphere plasma. It is this massive release of energetic
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