High Latitude Communications Satellite

Abstract

This paper presents preliminary design of a high latitude communications satellite. The satellite provides a continuous UHF communications for areas located north of the region covered by geosynchronous communications satellites. The satellite orbit is elliptic with 63.40 inclination with perigee at 1204 km altitude in the southern hemisphere and apogee at 14930 km altitude. The orbit period is 4.8 hours. The system consists of three satellites equally spaced in mean anomaly. It is launched by Delta II launch vehicle in three satellite staked configuration. The spacecraft uses three-axis-stabilization consisting of three reaction wheel system. Solar array surface is always normal to sun rays by spacecraft rotation about yaw axis and solar array drive rotation. The propulsion subsystem is a catalytic monopropellant hydrazine subsystem consisting of four 38-Newton and twelve 2-Newton thrusters. Electric power is provided by GaAs solar cell and nickel hydrogen batteries.