Accession Number:

ADA171338

Title:

Optimal, Impulsive, Direct Ascent, Time-Fixed Orbital Interception.

Descriptive Note:

Doctoral thesis,

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s):

• Heckathorn,William G.

Report Date:

1985-01-01

Pagination or Media Count:

115.0

Abstract:

A method for determining optimal impulsive trajectories is applied to minimum fuel, direct ascent, time-fixed intercept trajectories. The optimal trajectory is obtained by satisfying Lawdens necessary conditions expressed in terms of the primer vector. The vehicle is initially at rest on the surface of a spherical planet and the target is assumed to be in a circular, equatorial orbit around the planet. Results are presented and compared for two planetary models a non-rotating planet, and one rotating with an angular velocity approximating that of the Earth. Each model is investigated for transfers in which the launch point is in the same plane as the target orbit coplanar and in which the launch point is not in the target orbit plane noncoplanar. Parameters varied during the analysis include transfer time, target radius, initial position of the target in relation to the launch point, the latitude of the launch point, and the direction of the transfer trajectory, i.e. posigrade or retrograde. Cost comparisons are made between the various cases, and generalizations indicated. Author

Descriptors:

• *INTERCEPT TRAJECTORIES
• *RENDEZVOUS TRAJECTORIES
• *TRANSFER TRAJECTORIES
• *CIRCULAR ORBITS
• *EQUATORIAL ORBITS
• MATHEMATICAL MODELS
• ALGORITHMS
• THESES
• APPROXIMATION(MATHEMATICS)
• FUEL CONSUMPTION
• MOMENTUM
• PLANETS

Subject Categories:

• Spacecraft Trajectories and Reentry
• Ground Support Systems and Facilities for Space Vehicles

Distribution Statement:

APPROVED FOR PUBLIC RELEASE