Orbit determination and analysis for Aureole 2 rocket at 27:2 resonance

Abstract

The Aureole 2 rocket (1973-107 B) was launched on 26 December 1973 into an orbit of inclination 74° and eccentricity 0.1 and has an estimated lifetime of 30 years. The orbit has been determined from observations for 90 epochs between September 1983 and December 1984, during which time the orbit was expected to be influenced significantly by the effects of 27:2 resonance with the Earth's gravitational field: exact resonance occurred on 28 April 1984. The observations numbered nearly 7400, of which 344 were from the Hewitt cameras of the University of Aston which are sited at Herstmonceux in England, and Siding Spring in Australia. The orbital inclination and eccentricity of the orbits derived had standard deviations corresponding on average to positional accuracies of 130 m cross-track and 80 m in perigee distance. The variations in inclination and eccentricity have been analysed individually to determine values of two pairs of lumped harmonics of order 27 from each parameter; when these parameters were fitted simultaneously they gave three pairs of harmonics with standard deviations corresponding to accuracies of approximately 2.5 cm in geoid height.