Laboratory Investigations of Cloud Nuclei from Combustion of Space Shuttle Propellant

Abstract

Small quantities of solid rocket motor propellant, of the type to launch the Space Shuttle, were burned at ambient pressure in the laboratory to provide aerosol samples for characterization. A portion of each sample was injected into an isothermal cloud chamber and the remainder into a 770 ? holding tank. Portable ice nucleus (IN) counters, filter devices for IN determinations and a cloud condensation nucleus (CCN) counter sampled from the tank. The measurements show that particles resulting from the combustion of the propellant are active IN (3.3 ? 108 to 1.5 ? 1011 g?1 active at ?20°C). The portable counters and filters detected significantly fewer IN than the isothermal cloud chamber. The propellant aerosol is a prolific source of CCN that swamped the instrument.