JERS-1 development status

Abstract

The Earth Resources Satellite-1 (JERS-1) is an advanced remote sensing satellite carrying, as a mission instrument, an L-band synthetic aperture radar and optical sensors (OPS). The OPS feature short wavelength i.r. spectral bands and a stereoscopic imaging band. The satellite is unique with its combination of mission instruments and global coverage capability with Mission Data Recorder. The satellite development is progressing toward a scheduled launch in 1992, the International Space Year. It is a joint development program between the National Space Development Agency of Japan (NASDA) and the Ministry of International Trade and Industry (MITI). NASDA is responsible for developing the satellite bus, while MITI for the mission instruments. The satellite bus provides a stable platform with precision attitude control, large power supply and heat dissipation capabilities required for accommodating mission instruments. It is notable that the satellite bus is capable of accommodating many high power, large heat dissipating components of mission instruments within its limited space, mass and power. Featuring the satellite bus design are Japan's first use of strap-down, digital zero-momentum attitude control system, remarkably light-weight structure, active thermal control incorporating thermal louvers and heat pipes, use of Satellite Data Bus System, etc. Many of the design features derive from advanced R&D efforts preceeding the outset of the program. The program started in 1984 and the critical design review was held in July 1989. This paper presents outline of the satellite system, design features of subsystems and operation profiles, based on the CDR outcome. An emphasis is placed upon describing technical and operational aspects of the satellite bus.