Accession Number:

AD0603134

Title:

A SATELLITE LANDING CONTROL SYSTEM UTILIZING DRAG MODULATION,

Descriptive Note:

Corporate Author:

AVCO EVERETT RESEARCH LAB EVERETT MASS

Personal Author(s):

Report Date:

1961-08-01

Pagination or Media Count:

1.0

Abstract:

A system is developed which controls a satellite vehicle to a selected landing point using a minimum of on-board equipment and relying upon atmospheric drag as the only control force. The resulting system requires no attitude indicator or stabilized platform for instruments it employs just one accelerometer which is body-mounted and a modest computer. The development of this system begins with the derivation of a set of linearized differential equations which describe the deviation of the reentry trajectory from a prescribed nominal. These equations hold for trajectory parameters in the vicinity of circular orbital conditions which exist during the time when this system is capable of exercising an important degree of control. This description of the trajectory dynamic is simple enough to permit a rational approach to the design of the control system. The controlled variable is taken to be a pseudo difference in altitude from the nominal altitude at any time the controlling variable is taken to be the difference in drag acceleration from the nominal drag acceleration.

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE