from the getting-back-lost-gravity dept.
Less than three weeks after launch, the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission has successfully completed its first mission phase and demonstrated the performance of the precise microwave ranging system that enables its unique measurements of how mass migrates around our planet.
The twin spacecraft launched May 22 from California's Vandenberg Air Force Base. NASA and German Research Centre for Geosciences (GFZ) engineers and mission controllers at the German Space Operations Center in Oberpfaffenhofen then spent the first few days completing the mission's launch and early operations phase and moving into an 85-day in-orbit checkout period. Science operations will begin when that period has been successfully completed.
During the initial phase, the twin GRACE-FO satellites were maneuvered into their operational orbit formation approximately 137 miles (220 kilometers) apart. Spacecraft systems were powered on, checked out and found to be performing as expected. Engineers also activated both primary instruments: the accelerometers, which measure forces on the satellites other than gravity, such as atmospheric drag or solar radiation pressure; and the microwave ranging instruments, which precisely measure the distance changes between the two satellites as they orbit Earth. Variations in Earth's gravity field caused by changes in the distribution of Earth's mass on and beneath the planet's surface—such as groundwater withdrawal and ice melt—cause the distance between the two satellites to vary ever so slightly.
[...] GRACE-FO data will provide unique insights into Earth's changing climate, including large-scale changes in our planet's ice sheets and glaciers; Earth system processes that define our environment, such as droughts and earthquakes; and even the impacts of some human activities, such as changes in the levels of aquifers resulting from pumping underground water for use in agriculture. GRACE-FO observations promise to provide far-reaching benefits to society.