NEW DELHI—India and the U.S are working together to develop a dual-frequency synthetic aperture radar satellite – the NASA-ISRO Synthetic Aperture Radar (Nisar), expected to be launched in 2021.

The U.S. “will be the 20th country to sign up for a commercial launch by India,” says an official at the Indian Space Research Organization.

The next test will take place in Israel. If successful, it will be followed by a test aboard an Indian warship in October.