Posted: Fri, Jan 6, 2006, 8:17 AM ET (1317 GMT)
Topex/Poseidon, a joint US-French earth sciences mission, officially ended Thursday because of spacecraft problems. The spacecraft, launched in 1992, was designed to operate for five years, but continued working until a reaction control wheel failed on October 9. Spacecraft engineers concluded that the problem could not be resolved, and NASA, in conjunction with the French space agency CNES, terminated the mission Thursday. Topes/Poseidon performed measurements of ocean topography, including studies of seasonal and annual current changes, rising sea levels, and other data used by scientists to develop models of global tides and ocean circulation. A successor spacecraft, Jason, was launched in 2001; a similar spacecraft, the Ocean Surface Topography Mission, is scheduled for launch in 2008.
