China sent into orbit a clandestine remote sensing satellite Wednesday during a launch that was announced less than a day in advance.

A Long March 2C rocket blasted off at 0255 GMT Wednesday from the Taiyuan space base in northern China's Shanxi province. The two-stage booster, propelled by a noxious mix of hydrazine and nitrogen tetroxide, deftly guided the secret Yaogan 6 satellite into orbit, according to the official Xinhua news agency.

Tracking data indicate the rocket achieved a sun-synchronous orbit with an average altitude of about 300 miles.

China will use Yaogan 6 for land resource surveys, environmental surveillance, urban planning, crop yield estimates, disaster response, and space science experiments, Xinhua reported.

But Western analysts believe the spacecraft is actually a military reconnaissance satellite, possibly outfitted with a night-vision, cloud-piercing radar that can observe objects on the ground during darkness and all weather conditions.

The Yaogan series is likely a cover for a fleet of spy satellites carrying radars and digital optical observation equipment.

Yaogan satellites have been launched from Taiyuan and the Jiuquan space center.

The flight was the second space launch of the year for China, coming eight days after the launch of a new navigation satellite.