On May 22 2018, a joint US/German space mission was launched to track the continuous movement of water and other changes in the Earth’s mass.
The pair of spacecraft was launched by the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO), a joint NASA/Germany Research Center of Geosciences (GFZ).
“GRACE-FO will provide unique insights into how our complex planet operates,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate at NASA Headquarters. “Just as important, because the mission monitors many key aspects of the Earth’s water cycle, GRACE-FO data will be used throughout the world to improve people’s lives – from better predictions of drought impacts to higher quality information on use and management of water from underground aquifers.”
Over its five-year mission, GRACE-FO will monitor the movement of mass around the planet by measuring where and how the moving mass changes Earth’s gravitational pull. The gravity changes cause the distance between the two satellites to vary slightly. Although the two satellites orbit 137 miles (220 kilometers) apart, advanced instruments continuously measure their separation to within the width of a human red blood cell.