A secret military payload successfully launched aboard a Long March rocket early Wednesday, continuing a feverish pace of Chinese space activity that includes a mysterious orbital rendezvous, an upcoming lunar probe and preps for continued human missions.

It was the fifth launch in barely 50 days for China, and the second mission in that period lofting a clandestine Yaogan reconnaissance satellite.

Wednesday's launch began with the blastoff of a Long March 2D rocket at 0242 GMT (10:42 p.m. EDT Tuesday) from the Jiuquan space center in the desert of northwestern China, according to the state-run Xinhua news agency.

It was 10:42 a.m. Beijing time.

The 135-foot-tall launch vehicle placed Yaogan 11 and two smaller satellites on a path nearly 400 miles above Earth.

The Yaogan 11 payload orbited Wednesday will conduct scientific experiments, survey land resources, estimate crop yields and contribute to natural disaster response efforts, Xinhua reported.

But the Yaogan satellite series are believed to provide the Chinese military with high-resolution reconnaissance imagery through electro-optical cameras and night-vision radar systems.

The successful rocket mission marked the 9th time China launched a satellite so far this year, and the country's government has several more flights on the books through the end of 2010.

The Long March manifest will continue with the expected launch of the Chang'e 2 orbiter to the moon in late September or early October.

Next year, China plans to send its Tiangong 1 module to space. A series of unmanned and manned Shenzhou capsules will visit the module, forming a modest space station for long-duration research missions by Chinese astronauts.

But more Chinese space developments are occurring 350 miles up, where two technology demonstration satellites have been flying in close formation since the middle of August.

Amateur satellite observers spotted the SJ-12 spacecraft approaching an older platform named SJ-6F, computing the objects approached within 200 meters, or 656 feet, of each other, based on published U.S. Air Force tracking data.

The satellites flew apart and closed their distance again in late August. Since then, analysts say, the Shijian spacecraft have maintained a separation of just a few miles, demonstrating stable station-keeping capabilities.

Chinese space officials have been silent on the matter, although state media repeated a Russian news report citing the observations of Igor Lissov, a respected space expert who released one of the earliest accounts of the rendezvous in August.