Title

Flight Simulation of Orbital and Reentry Vehicles Part I - Development of Equations of Motion in Six Degrees of Freedom

Description

Equations governing the motion of a lifting reentry vehicle in six degrees of freedom are developed for simulation purposes. Effects of earth rotation, earth oblateness and wind velocity are included. The rotational equations are conventional equations involving angular rates referred to body axes. Two different formulations of the translational equations are presented, using different coordinate systems. One involves spherical coordinates referred to the equatorial plane of the rotating earth; the other involves spherical coordinates referred to a nominal trajectory plane fixed with respect to inertial axes. The former has the advantage that earth rotation and oblateness are taken into account more simply, but an indeterminacy is encountered in the event of flight over a pole. The latter formulation eliminates this indeterminacy but is otherwise more complex.

It is concluded that the equations developed are suitable for digital or hybrid analog-digital computation, but that accuracy requirements would be excessive for analog computation exclusively. An alternative formulation, suitable for analog computation, is presented in Part II of the present series.

Date

1961

Index Abstract

Contrails and DTIC

Photo Quality

Not Needed

Report Number

ASD TR 61-171 (I)

Corporate Author

University of Michigan

Laboratory

Behavioral Sciences Laboratory

Extent

41

Identifier

AD0269282

AD0269282

Access Rights

OTS

Distribution Classification

1

Contract

AF 33(616)-5644

DoD Project

6114

DoD Task

611407

DTIC Record Exists

Yes

Distribution Change Authority Correspondence

None

Abstract

Equations governing the motion of a lifting reentry vehicle in six degrees of freedom are developed for simulation purposes. Effects of earth rotation, earth oblateness and wind velocity are included. The rotational equations are conventional equations involving angular rates referred to body axes. Two different formulations of the translational equations are presented, using different coordinate systems. One involves spherical coordinates referred to the equatorial plane of the rotating earth; the other involves spherical coordinates referred to a nominal trajectory plane fixed with respect to inertial axes. The former has the advantage that earth rotation and oblateness are taken into account more simply, but an indeterminacy is encountered in the event of flight over a pole. The latter formulation eliminates this indeterminacy but is otherwise more complex.

It is concluded that the equations developed are suitable for digital or hybrid analog-digital computation, but that accuracy requirements would be excessive for analog computation exclusively. An alternative formulation, suitable for analog computation, is presented in Part II of the present series.

Report Availability

Full text available

Date Issued

1961-10

Provenance

RAF Centre of Aviation Medicine

Type

report

Format

1 online resource (viii, 33 pages) : ill.

Creator

Isakson, Gabriel

Subject

Flight Simulators

Reentry Vehicles

Artificial Satellites

Atmosphere Entry

Differential Equations

Dynamics

Equations

Flight Paths

Mathematical Analysis

Orbits

Pilots

Training Devices

Publisher

Wright-Patterson Air Force Base, OH : Behavioral Sciences Laboratory, Aerospace Medical Laboratory, Aeronautical Systems Division, Air Force Systems Command, United States Air Force

Distribution Conflict

No