‘Skimming' the atmosphere, GOCE was flying so low around Earth (about half the altitude of the International Space Station) that the air was still rather dense, meaning it experienced significant drag forces during its life in orbit.
This ‘fast and low’ orbit presented unique challenges to mission teams at ESA’s ESOC mission control in Germany, from where GOCE was flown. In order to determine this, the “mathematical figure of the Earth”, GOCE had to fly as low in orbit as possible, so as to sense the minute variations in Earth’s gravitational field.
Launched in 2009 on a Rockot launcher from northern Russia, GOCE spent four years mapping Earth’s gravity with unrivalled precision, resulting in a unique model of the ‘ geoid’ - the hypothetical shape that the surface of the oceans would take under only the influence of Earth’s gravity and rotation, ignoring the influence of winds and tides.īetter understanding of Earth’s gravity field and its associated geoid provides insight into global ocean circulation patterns, and these play a crucial role in climate regulation. Operating in the lowest-ever orbit of any Earth observation satellite, GOCE was on the edge of space flying at an altitude of just 224 km.
GOCE (pronounced go-chay), the Gravity Field and Steady-State Ocean Circulation Explorer, was one of ESA’s most remarkable missions.
