Pollution of the upper atmosphere by rockets

Abstract

This report estimates the amounts of various constituents that would have to be continually injected by rockets into the upper atmosphere in order to double the worldwide natural concentrations there. Involved in the calculations are: (a) the natural atmospheric abundances of constituents such as H2O, CO2, NO, Na, K, Li, H, etc.; (b) the residence times in various regions of the atmosphere, since these determine how rapidly a constituent will be removed; and (c) the chemical or photochemical stability of a substance exposed to the upper atmosphere environment. It is concluded that a doubling of the CO2, H2O, or NO content would require per year on the order of 103 to 105 Saturn-type rockets, each injecting 100 tons of exhaust above 100 km. On the other hand, a few hundred small rockets per year, each containing 10 kg of the chemical, would probably double the Na content; similarly, less than two such rockets per year would be expected to double the Li content. These last conclusions have implications for future tracer experiments using these substances.