A SpaceX rocket Tuesday blasted off a duo of sports car-sized satellites built by the US and Germany to reveal changes in sea level rise, ice melt and drought on Earth.
"Three, two, one, liftoff!" said a SpaceX commentator as the Falcon 9 rocket launched from Vandenberg Air Force Base in California at 12:47 pm Pacific time (1947 GMT).
The $521 million payload is called the Gravity Recovery and Climate Experiment Follow-on (GRACE-FO).
It picks up from GRACE, a satellite pair that launched in 2002 and tracked, among other things, precisely how much ice was lost each year in Greenland and Antarctica until 2017.
Groundwater, oceans, lakes, rivers and ice sheets will be monitored by the twin satellites, a joint mission between the US space agency and German Research Centre for Geosciences (GFZ).
The pair will fly 137 miles (220 kilometers) apart, or about the distance from Los Angeles to San Diego.
The SpaceX Falcon 9 rocket carrying satellites to study changes in sea level, ice melt and drought as seen in this NASA photo before liftoff at the Vandenberg Air Force Base in California