On March 17, 2002, the German-U.S. satellite duo GRACE (Gravity Recovery and Climate Experiment) was launched to map the global gravitational field with unprecedented precision. The mission lasted 15 years, more than three times as long as expected. When the two satellites burned up in the Earth’s atmosphere at the end of 2017 and beginning of 2018, they had recorded the Earth’s gravitational field and its changes over more than 160 months.