The orbital lifetimes of Molniya satellites.
Abstract
Between 1965 and 1974, forty Molniya communication satellites were launched by the USSR into highly elliptic orbits with a period near 12 hr, initial perigee height near 500 km and initial inclinations of either 65 or 63 deg. The orbits of the Molniyas are strongly affected by lunisolar perturbations, and the satellites decay when the perigee is forced down to near 100 km height by these perturbations, which are normally calculated by numerical integration. In this paper an approximate analytical method is developed for 65 deg Molniyas which shows that the lifetime must be between 1 and 7 years and successfully defines the domain of permissible lifetimes as a function of the initial right ascension of the node. The lifetimes of all the satellites lie within or very near the boundaries of this domain. For the 63 deg Molniyas the analytical approximations indicate that there is a small chance of decay within 4 years, and a good chance of decay between 9 and 13 years from launch, if right ascension of the node lies between 90 and 270 deg. If the perigee librates about southern apex and the absolute value of the node is less than 90 deg, no upper limit to the lifetime can be set.
 Publication:

Journal of the British Interplanetary Society
 Pub Date:
 December 1975
 Bibcode:
 1975JBIS...28..783K
 Keywords:

 Elliptical Orbits;
 Molniya Satellites;
 Orbit Decay;
 Satellite Lifetime;
 Numerical Integration;
 Orbit Calculation;
 Orbit Perturbation;
 Performance Prediction;
 Perigees;
 Astrodynamics