The two GRACE (Gravity Recovery and Climate Experiment) satellites have continuously mapped the Earth's gravity field during their 15-years mission.
The GRACE satellites have been developed and produced by Astrium GmbH in Friedrichshafen, Germany for NASA/JPL.
Credit: Astrium/Airbus Defence and Space, GFZ
Today, March 17 the twin GRACE satellites have celebrated their 15th anniversary. This is three times longer than originally planned and they have helped scientists to perform climate change related studies based on GRACE mass transport data.
Further details can be found in the following GFZ press release (Link).
And a video presentation made by colleagues at JPL can be seen here.