Lanterna Rally

Author: Norman Sissenwine

Publisher:

Published: 1971

Total Pages: 48

ISBN-13:

The influence of atmospheric density on ballistic trajectories of re-entry vehicles usually attains a maximum below 20 kilometers. The most direct and accurate means of estimating this influence is from profiles of density specified at uniform intervals of altitude (usually 2 km) from individual soundings for the time and over the area of re-entry. Unfortunately, vertical distances between levels on constant pressure charts, normally available for obtaining density profiles, are generally greater than 2 kilometers. Unless interpolation between these pressure surfaces for obtaining densities at the 2-km intervals is based on the actual density-altitude relation, the interpolated densities will be in error. Three often-used methods of interpolation are: (1) assumption of a linear decrease of density with altitude, (2) assumption of a linear decrease of the logarithm of density with altitude, and (3) assumption of a linear decrease of density multipliers with altitude, where a density multiplier at the altitude of a constant pressure surface represents the ratio of density to the Standard Atmosphere density at that altitude. The three methods with resultant errors are discussed and evaluated in this report. (Author).