China launched a Long March 4B rocket Wednesday carrying two Tianhui radar mapping satellites into orbit more than 300 miles in altitude. The two satellites will join a similar pair of spacecraft launched in April 2019, working in tandem to bounce radar beams off Earth’s surface to generate detailed three-dimensional global maps.
The satellite mapping system uses a technique called interferometric synthetic aperture radar to gather stereo data for 3D topographic maps. The data will be used by Chinese military and civilian agencies.
The two new Tianhui 2 satellites, known as the Tianhui 2-02 pair, took off at 6:32 p.m. EDT (2232 GMT) Wednesday from the Taiyuan launch base in northern China’s Shanxi province atop a Long March 4B rocket.
Liftoff occurred at 6:32 a.m. Thursday Beijing time, kicking off China’s 29th orbital launch attempt of the year.
U.S. military tracking data indicated the rocket deployed the two Tianhui 2-02 satellites into a near-circular polar orbit at an average altitude of 317 miles (511 kilometers), with an inclination of 97.45 degrees to the equator.