MINIMUM FUEL ANALYSIS OF A LUNAR SOFT LANDING MISSION USING FEEDBACK CONTROL.
Abstract
The problem of making a soft landing on the moon's surface with a vehicle using conventional chemical rocket engines with restart capability was studied in this paper. In particular, a minimum fuel control scheme utilizing readily computed controls has been sought and found. By studying the problem from a constant gravity viewpoint, it was found that by running several extremal trajectories backwards from the moon's surface, some very interesting similarities in the trajectories were noticed. When the thrusting angle was plotted against velocity direction for the various extremal trajectories, these curves fell very close together for the low thrust case, and fell on the same curve for medium and high thrust cases (see charts). The results of this paper show that a very simple feedback control exists which is for all practical purposes optimal. The trajectory has a thrust profile which is full on, or off in a coasting phase, depending on the initial conditions and the landing point desired.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1965
- Accession Number
- AD0624681
Entities
People
- John R. Hoffman
Organizations
- University of Michigan