15TH-Order Harmonics in the Geopotential, from Analysis of Decaying Satellite Orbits.
Abstract
A satellite with an initial orbital period greater than about 96 minutes will, as it decays under the action of air drag, pass through 15th-order resonance when successive equator crossings are exactly 24 degrees apart, so that each day the satellite follows a fixed set of 15 ground tracks. If the decay is slow enough, the inclination i of the orbit to the equator changes appreciably as the satellite passes through resonance, because of the build-up of perturbations caused by the tesseral harmonics in the Earth's gravitational potential of order 15 and degree 15, 17, 19, 21 ... . Equations between the coefficients of these harmonics can be obtained by analyzing the changes in orbits at a variety of inclinations, offering a method of evaluating 15th-order harmonics almost free of contamination from other harmonics. The paper describes the results so far obtained in these studies, from the satellites Ariel 3 (i = 80 degrees), Transit 1B (i = 51 degrees), Cosmos 373 (i = 63 degrees) Cosmos 387 (i = 74 degrees). A set of values is derived for the coefficients of order 15 and degree 15, 17, 19 and 21. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1972
- Accession Number
- AD0750424
Entities
People
- Desmond King-Hele
Organizations
- Royal Aircraft Establishment