GOCE: the first core Earth explorer of ESA's Earth observation programme

Abstract

Scheduled for launch in 2005, the Gravity Field and Steady State Ocean Circulation Explorer ( GOCE) satellite is the first of the Earth Explorer Core Missions planned as part of ESAs Earth Observation Programme. The aim of the GOCE mission is to provide global and regional models of the Earth's gravity field and of the geoid, its reference equipotential surface, with high spatial resolution and accuracy. Such an advance in the knowledge of the Earth's gravity field will help develop a much deeper understanding of the physics of the Earth's interior, the interaction of the continents and the ocean circulation. To achieve its objectives, the GOCE mission will have to satisfy the following requirements: • uninterrupted tracking of the satellite in three spatial dimensions; • measurement and compensation of the effect of the non-gravitational forces; • orbital altitude as low as possible; • enhance the strength of the high-frequency component of the gravity signal by differentiation. The above-mentioned requirements drive the design of the satellite which will be configured to minimise aerodynamic drag and will carry as payload a highly sophisticated three-axis gradiometer and a GPS/GLONASS receiver. The Phase B of the GOCE satellite started at the end of 2000 and will last for 1 year. The paper will briefly recall the mission, its challenges and the performances of the satellite, then focusing on the description of the various elements of the system design (instruments, platform, etc.) and on the envisaged operation strategy.