In-Flight Winds from the Drift of a Rocket Exhaust Trail

Abstract

The study presents an analysis of free drift of the exhaust trail obtained from television photos of India's satellite launch vehicle, ASLV-D2, in flight. Triangulation is not possible, necessitating the use of in-flight trajectory data and a wind model for line-of-sight drift correction in the analysis. The crosswind component, up to the height of 11.7 km where the mission tailed, and the associated vertical wind shears have been estimated. The crosswind magnitude above 9 km appears close to the summer extreme (95th percentile) for the launch station. On a 300-m vertical scale, the in-flight estimate of wind velocity is observed to be significantly different from the only available rawin data obtained 6 h prior to launch. The analysis points to a possibility of the launch vehicle passing through a turbulence zone between the altitude range of 7.4?7.6 km.