Flight Simulation of Orbital and Reentry Vehicles Part IV - A Study of Earth Oblateness Effects and Characteristic Oscillatory Motions of a Lifting Reentry Vehicle
Report Number: ASD TR 61-171 (IV)
Author(s): Isakson, Gabriel
Corporate Author(s): University of Michigan
Laboratory: Behavioral Sciences Laboratory
Date of Publication: 1961-12
Pages: 26
Contract: AF 33(616)-8385
DoD Project: 6114
DoD Task: 611407
Identifier: AD0274251
Abstract:
The present report is concerned with two distinct aspects of the simulation problem for a lifting reentry vehicle. The first relates to the effects of earth oblateness on the flight path of such a vehicle. The effects of oblateness of the gravity field on the orbital motion of a satellite are surveyed and are found to be small for a single orbit, probably sufficiently small to be neglected in a simulation for training purposes. Some of these effects are cumulative and would become substantial in a flight of long duration. The effects of oblateness of the earth's surface and atmosphere on the reentry trajectory are studied independently of the gravity oblateness effects. Typical trajectories are computed for the case of a nonrotating earth. Under the most extreme conditions, there is found to be a change in range of 690 nautical miles for a nominal once-around flight. The second aspect relates to the characteristic oscillatory motion of the vehicle during reentry. The pertinent literature on the topic is surveyed. Approximate expressions for the period of the characteristic long-period and short-period oscillations are presented.
Provenance: RAF Centre of Aviation Medicine
Author(s): Isakson, Gabriel
Corporate Author(s): University of Michigan
Laboratory: Behavioral Sciences Laboratory
Date of Publication: 1961-12
Pages: 26
Contract: AF 33(616)-8385
DoD Project: 6114
DoD Task: 611407
Identifier: AD0274251
Abstract:
The present report is concerned with two distinct aspects of the simulation problem for a lifting reentry vehicle. The first relates to the effects of earth oblateness on the flight path of such a vehicle. The effects of oblateness of the gravity field on the orbital motion of a satellite are surveyed and are found to be small for a single orbit, probably sufficiently small to be neglected in a simulation for training purposes. Some of these effects are cumulative and would become substantial in a flight of long duration. The effects of oblateness of the earth's surface and atmosphere on the reentry trajectory are studied independently of the gravity oblateness effects. Typical trajectories are computed for the case of a nonrotating earth. Under the most extreme conditions, there is found to be a change in range of 690 nautical miles for a nominal once-around flight. The second aspect relates to the characteristic oscillatory motion of the vehicle during reentry. The pertinent literature on the topic is surveyed. Approximate expressions for the period of the characteristic long-period and short-period oscillations are presented.
Provenance: RAF Centre of Aviation Medicine