Jul 21 2003
From The Space Library
NASA announced the release of the first scientific product of the Gravity Recovery and Climate Experiment (GRACE) mission, a joint effort of NASA and the German Aerospace Center. The GRACE mission had produced the most accurate map to date of Earth's gravity field, using preliminary data collected over 111 days. Project scientists had created the map from selected data, which they had used to calibrate and validate the instruments of the pair of American and German satellites comprising GRACE. The satellites had measured Earth's gravitational force from orbits 500 kilometers (310.7 miles) high, with 220 kilometers (136.7 miles) separating them, making a pass of the entire planet once each month, and producing measurements of unprecedented accuracy. The measurements provided precise views of ocean currents and tidal changes, enabling scientists to better understand how the oceans affect climate. Although the data was preliminary, NASA had released it to oceanographers immediately, months in advance of the scheduled start of routine GRACE scientific operations, underscoring the mission's importance and the data's value. (NASA, “Oceanographers Catch First Wave of Gravity Mission's Success,” news release 03-244, 21 July 2003, http://www.nasa.gov/home/hqnews/2003/jul/HQ_03244_gravity_success.html (accessed 23 December 2008); Larry O'Hanlon, “Gravity Map Shows Earth Is Very Lumpy,” Discovery News, 29 July 2003.
NASA announced the successful implementation of new software in three computers controlling the precision pointing of NASA's Far Ultraviolet Spectroscope Explorer (FUSE) satellite. In mid-April 2003, NASA had installed the software for the spacecraft's Attitude Control Instrument Data System and the processor for the Fine Error Sensor guide camera, and testing of the new configuration had been ongoing since that time. George Sonneborn, FUSE Project Scientist at NASA's GSFC, explained that the uploaded software would allow FUSE to operate with any number of gyroscopes, or none, in the event of gyroscope failure. Tests showed that FUSE could operate with no gyroscopes without experiencing any degradation in quality of scientific data and with only a slight loss of efficiency in scheduling observations. Before the new software installation, FUSE had required at least one operating gyroscope on each of its three axes to conduct normal scientific operations. (NASA, “NASA Team Gives Fuse Spacecraft Triple Brain Transplant,” news release 03-243, http://www.nasa.gov/home/hqnews/2003/jul/HQ_03243_fuse_transplant.html (accessed 23 December 2008).
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