On March 17, 2002, a pair of satellites nicknamed “Tom” and “Jerry” launched aboard a Russian Rockot vehicle from the Plesetsk Cosmodrome in Russia. It was the start of the Gravity Recovery and Climate Experiment, aka GRACE, a partnership mission between NASA and the German space agency (DLR) to map Earth’s gravity field and how it changes over time due to the movement and variations of surface and ground water. Originally planned to be a five-year mission, GRACE has now been continuously operating in orbit for over 15 years, and has revealed much about what’s been happening to the water on—and in—our planet.
“With GRACE, we effectively created a new field of spaceborne remote sensing: tracking the movement of water via its mass,” said Michael Watkins, director of NASA’s Jet Propulsion Laboratory in Pasadena, California.
Some of the things GRACE has discovered are:
• Land ice melt rates in Greenland and Antarctica are increasing;
• One-third of Earth’s large groundwater basins are being depleted;
• Groundwater reserves have dwindled in much of the southern United States;
• In many places around the globe groundwater is being extracted faster than can be naturally replenished. (Source)
Even though Tom and Jerry have been operating well through their main and extended missions they will finally run out of fuel this summer. But the next generation of GRACE spacecraft is already planned with the GRACE Follow-On (GRACE-FO) mission, slated to launch at the end of 2017 or early 2018.
The video below is a touching tribute to the GRACE mission, and a promise of continued research to come with GRACE-FO.
“Through GRACE-FO, we will extend into the next decade our capacity to gain an accurate picture of the global water cycle,” said Frank Webb, GRACE-FO project scientist.
Lights in the Dark 
That was very nice, and of course sad. 😦 I love space, too. 🙂
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