Aerosols and Trace Gases in the Effluents Produced by the Launch of Large Liquid- and Solid-Fueled Rockets

Lawrence F. Radke Department of Atmospheric Sciences, University of Washington. Seattle 98195

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Peter V. Hobbs Department of Atmospheric Sciences, University of Washington. Seattle 98195

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Dean A. Hegg Department of Atmospheric Sciences, University of Washington. Seattle 98195

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Abstract

Airborne measurements over periods of several hours were made in the effluents that collected in the boundary layer in the form of “ground clouds” when an Atlas/Centaur and Titan III rocket were launched at night-time from Cape Canaveral, Florida. The ground cloud produced by the ATLAS was dry, whereas that produced by the TITAN was initially wet, then dry, and finally wet again. Both clouds dispersed primarily in the horizontal plane. Their volumes at time t (min) were given by V = V0tn where V0 = 1.3 × 106 m3 and n = 0.98 for the ATLAS and V0 &equals 1.76 × 107 m3 and n = 0.94 for the TITAN.

The ATLAS ground cloud initially contained elevated concentrations of NO, N02, hydrocarbons and particulate mass. However, dispersion of the cloud quickly reduced these concentrations and the light-scattering coefficient of the cloud. Gas-to-particle conversion (postulated to be the result of the oxidation of NO to NO2 followed by the Formation of NH4NO3) produced smoke particles at a rate of - ∼1016 s−1 in the ATLAS ground cloud but these did not contribute significantly to the total mass of particles in the cloud.

Gas-to-particle conversion in the TITAN ground cloud during its dry phase (probably produced by the reaction of HCI, from the rocket exhausts, with NH3, from the ambient air, to produce NH4Cl) created mass at a sufficient rate (∼0.1 μg m−3 min−1) to provide the potential for a significant source of pollution for several days.

Abstract

Airborne measurements over periods of several hours were made in the effluents that collected in the boundary layer in the form of “ground clouds” when an Atlas/Centaur and Titan III rocket were launched at night-time from Cape Canaveral, Florida. The ground cloud produced by the ATLAS was dry, whereas that produced by the TITAN was initially wet, then dry, and finally wet again. Both clouds dispersed primarily in the horizontal plane. Their volumes at time t (min) were given by V = V0tn where V0 = 1.3 × 106 m3 and n = 0.98 for the ATLAS and V0 &equals 1.76 × 107 m3 and n = 0.94 for the TITAN.

The ATLAS ground cloud initially contained elevated concentrations of NO, N02, hydrocarbons and particulate mass. However, dispersion of the cloud quickly reduced these concentrations and the light-scattering coefficient of the cloud. Gas-to-particle conversion (postulated to be the result of the oxidation of NO to NO2 followed by the Formation of NH4NO3) produced smoke particles at a rate of - ∼1016 s−1 in the ATLAS ground cloud but these did not contribute significantly to the total mass of particles in the cloud.

Gas-to-particle conversion in the TITAN ground cloud during its dry phase (probably produced by the reaction of HCI, from the rocket exhausts, with NH3, from the ambient air, to produce NH4Cl) created mass at a sufficient rate (∼0.1 μg m−3 min−1) to provide the potential for a significant source of pollution for several days.

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