Lidar Detection of Subvisible Reentry Vehicle Erosive Atmospheric Material.

摘要

This report describes a lidar technique employed to detect conventionally undiscernible atmospheric particulate concentrations which cause unexpected nose-cone erosions of reentry missiles. It also describes the experiment,data,and data analysis results obtained during several Athena-H reentry missions conducted at White Sands Missile Range,New Mexico. Lidar data recorded on the Athena-H reentry nights of 26April and 24August 1973provided information on subvisible tenuous layers located at heights of 9.3km and 14.3km,respectively. Analysis of the lidar data,concurrently recorded radiosonde meteorological data,and a clear day aerosol model yielded an average volume backscattering coefficient of 0.000043/m for the 9.3km layer which was 310 m thick and 0.000032/m for the 14.3km layer which was 500 m in depth. Calculations based on previous in-situ measurements of particulate sizes and elemental composition yielded an average concentration of 3.7 x 10to the 5th power liquid droplets/cu/m or 26,000ice crystals/cu/m for the 26April cloud striation and an average concentration of 20,000ice particles/cu/m or 2.2 x 10to the 8th power arid particles/cu/m for the 24August layer. The lidar data clearly distinguished between a truly clear atmospheric path, 21March,and an apparently clear atmospheric path, 26April and 24August. (Author)