Mar 17 2009
From The Space Library
ESA successfully launched its Gravity Field and Steady-State Ocean Circulation Explorer (GOCE), the first of seven planned ESA Earth Explorer satellites, aboard a Rockot/Breeze-KM launch vehicle from Plesetsk Cosmodrome at 14:21 (UT). ESA had designed GOCE to measure Earth’s gravitational field, so that ESA could use the data to create very high-resolution maps that would provide the baseline for measurements of ocean circulation and sea-level change. The 1,100-kilogram (2,425-pound) spacecraft was 5 meters long (16.4 feet long) by 1 meter wide (3.3 feet wide). GOCE had fixed solar arrays, designed to produce 1.3 kilowatts of power. To enable the craft to acquire the high-resolution measurements, ESA had designed GOCE to travel in a near-polar orbit at an altitude of only 263 kilometers (163.4 miles), rather than at the altitude of 600 to 900 kilometers (372.8 to 559.2 miles) typical for Earth-observation satellites. Mission managers remarked that, to their knowledge, nonmilitary satellites had never before operated in this orbit, an altitude that has significant atmospheric drag effects. To counteract the atmospheric drag, which could slow the spacecraft and potentially cause a premature end to the mission, GOCE had a unique arrowhead-like design that improved its aerodynamics. Additionally, ESA had designed the craft with a xenon-ion propulsion engine that would provide gentle thrust against the effects of the drag.
Spacewarn Bulletin, no. 665; Peter B. De Selding, “Russian Rocket Lofts ESA Gravity Mapping Satellite,” Spacenews.com, 17 March 2009, http://www.spacenews.com/civil/russian-rocket-lofts-esa-gravity-mapping.html (accessed 10 May 2011).
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