Analysis of the orbit of Cosmos 72 (196553B) near 15thorder resonance
Abstract
Cosmos 72 (196553B) was launched on 16 April 1965 into a nearcircular orbit with an average height of 570 km and inclination 56°. Over the years, the orbit has contracted slowly under the influence of air drag, and On 27 June 1972 passed through exact 15thorder resonance, when successive equator crossings are 24° apart in longitude and the ground track repeats after 15 rev. The orbit has been determined at seven epochs between April 1972 and February 1973, using the RAE orbit refinement program PROP, with 544 optical and radar observations: the average orbital accuracy is about 50 m in height and 0.0008° in inclination. For Cosmos 72 the change in inclination at 15thorder resonance, due to perturbations by 15thorder harmonics in the geopotential, is greater than for any satellite previously analysed  nearly 0.07°  and analysis of the change, using the seven PROP orbits and 45 U.S. Navy orbits, yields equations accurate to 4 per cent for the geopotential coefficients of order 15 and odd degree (15, 17, 19 …). A similar analysis of the variation in eccentricity gives less accurate equations for coefficients of order 15 and even degree (16, 18 …). The variations in right ascension of the node and argument of perigee have also been analysed.
 Publication:

Planetary and Space Science
 Pub Date:
 September 1974
 DOI:
 10.1016/00320633(74)900452
 Bibcode:
 1974P&SS...22.1269K
 Keywords:

 Cosmos Satellites;
 Eccentric Orbits;
 Orbit Perturbation;
 Orbital Resonances (Celestial Mechanics);
 Resonance;
 Satellite Orbits;
 Computer Techniques;
 Curve Fitting;
 Geopotential;
 Inclination;
 Orbital Mechanics;
 Perigees;
 Zonal Harmonics;
 Astrodynamics