Accession Number : AD0700513

Title :   ORBITAL STABILIZATION OF 12-HOUR SATELLITES.

Descriptive Note : Technical rept.,

Corporate Author : ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (ENGLAND)

Personal Author(s) : Allan,R. R.

Report Date : JUL 1969

Pagination or Media Count : 29

Abstract : Artificial Earth satellites with periods of approximately 12 hours are subject to resonance effects similar to those suffered by synchronous satellites. Highly eccentric 12-hour orbits at an inclination of about 63.4 degrees are of special interest, since the apogee can remain in the Northern hemisphere. There is a stable state in which the ground track is fixed relative to the Earth, and the position of the stable ground track depends on the argument of perigee omega and on the eccentricity. Since there is scope for choice in the value of omega, it is possible to arrange that apogee occurs over Western Europe, for example. Such a satellite would be visible at a high angle of elevation from the whole of Western Europe for at least six hours. This system possesses some advantages over synchronous satellites for communications within a limited region of the Earth. Russian communication satellites have been of this type, with eleven Molniya 1 launches and three satellites in the Cosmos series to date. The advantages of a stable ground track, however, have not been much used in the Molniya system. (Author)

Descriptors :   (*COMMUNICATION SATELLITES(ACTIVE), ORBITS), (*ORBITS, STABILITY), RESONANCE, PERIGEE, ORBITS, AREA COVERAGE, SATELLITE TRACKING SYSTEMS, GREAT BRITAIN

Subject Categories : Spacecraft Trajectories and Reentry

Distribution Statement : APPROVED FOR PUBLIC RELEASE