Gravity Recovery and Climate Experiment
Artist's concept of the twin GRACE satellites
|
|
| Names | GRACE Tom and Jerry |
|---|---|
| Operator | NASA and German Aerospace Center (DLR) |
| COSPAR ID | 2002-012A and 2002-012A |
| SATCAT no. | 27391 and 27392 |
| Website | GRACE |
| Mission duration | Five-year primary mission extended |
| Spacecraft properties | |
| Manufacturer | Space Systems/Loral and Astrium GmbH |
| Launch mass | 487 kg (1,074 lb) each |
| Start of mission | |
| Launch date | 09:21, March 17, 2002 |
| Rocket | Rokot |
| Launch site | Plesetsk Cosmodrome |
| Orbital parameters | |
| Reference system | Geocentric |
| Semi-major axis | 6,700 km (4,200 mi) |
| Eccentricity | 0.001 |
| Perigee | 483 km (300 mi) |
| Apogee | 508 km (316 mi) |
| Inclination | 89.0° |
| Period | 91 min |
The Gravity Recovery And Climate Experiment (GRACE), a joint mission of NASA and the German Aerospace Center, has been making detailed measurements of Earth's gravity field anomalies since its launch in March 2002. Gravity is determined by mass. By measuring gravity anomalies, GRACE shows how mass is distributed around the planet and how it varies over time. Data from the GRACE satellites is an important tool for studying Earth's ocean, geology, and climate. GRACE is a collaborative endeavor involving the Center for Space Research at the University of Texas, Austin; NASA's Jet Propulsion Laboratory, Pasadena, Calif.; the German Space Agency and Germany's National Research Center for Geosciences, Potsdam. The Jet Propulsion Laboratory is responsible for the overall mission management under the NASA ESSP program.
The principal investigator is Dr. Byron Tapley of the University of Texas Center for Space Research, and the co-principal investigator is Dr. Christoph Reigber of the .
The GRACE satellites were launched from Plesetsk Cosmodrome, Russia on a Rockot (SS-19 + Breeze upper stage) launch vehicle, on March 17, 2002. The spacecraft were launched to an initial altitude of approximately 500 km at a near-polar inclination of 89°. The satellites are separated by approximately 200 km along their orbit track. GRACE has far exceeded its designed five-year lifespan. As of March 2017[update] the GRACE spacecrafts orbit has decayed by 150km, and is continuing to decay at 30km/year. Its successor, GRACE Follow-On, is expected to launch in 2017/18
The monthly gravity anomalies maps generated by GRACE are up to 1,000 times more accurate than previous maps, substantially improving the accuracy of many techniques used by oceanographers, hydrologists, glaciologists, geologists and other scientists to study phenomena that influence climate.
...
Wikipedia