Antenna pointing mechanism for ESA ENVISAT polar platform

INTA is currently developing a two-degree-of-freedom antenna pointing mechanism (APM) as part of the ESA ENVISAT POLAR PLATFORM (PPF) program. This mechanism will drive a Ka-band antenna within the Data-Relay Satellite System (DRS) on board the Polar Platform satellite. The first mission using PPF is ENVISAT, which is expected to be flown in 1998. This paper describes the main requirements, design, and test results of this pointing system, as well as the main technical problems from customer requirements and how those have been faced to achieve a final design.