So far, calculations have shown that one of the major atmospheric effects of rocket effluents will occur in the ionospheric layer referred to as the F2 region (see Fig. 3.1). Here, exhaust products act to remove a large fraction of the total number of electron-ion pairs from the ionospheric region surrounding the position of the rocket burn. In the case of the 1973 NASA Skylab launch, the depleted region covered an area 2000 km in width for a period of several hours. Similar depletions, but of smaller scale, have been deliberately created in the 1977 experiments named LAGOPEDO. Theoretical predictions verified by these observations included enhanced airglow (visible emissions from excited molecules) and electron-ion pair depletion. Additional experiments and further analysis of data will be required to verify the occurrence of thermal effects and the formation of plasma striations that can cause interference with radio communication systems. The enhanced airglow, while not sufficient to cause harmful effects at ground level, may contribute to the background interference to optical sensing devices employed in satellite surveillance systems. The potential impacts of electron-ion removal and possible thermal effects are not well understood at this time and will be examined during FY 1979 and FY 1980, as will the nature and extent of the depletions themselves. To date only individual rocket launch effects have been observed and only preliminary calculations of multiple launch effects have been attempted. Much more theoretical emphasis will be placed on multiple rocket launch effects in the future. Beyond 500 km the major rocket propulsion system effluents will be heavy ions (argon ions) with smaller amounts of chemical propellants. Preliminary calculations suggest that the mass and energy increase in the plas- maspheric region surrounding the satellites will be substantially increased during transfer of the satellite cargo from low (550 km) to geosynchronous (35,000 km) earth orbit. The impacts of such increases will be undertaken and some experiments have been suggested to improve our understanding of these effects during the next two years. The SPS satellites themselves, composed of large metallic structures, may pose some hazards to the environment both in the vicinity of the satellites and perhaps even closer to the biosphere. First the satellites will tend to collect particles as they sweep through the ambient plasmasphere. Second, they may develop fairly large electric and magnetic fields as a result
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