China launched a pair of Shijian research satellites Oct. 6 atop a Long March 4B rocket, according to the state-run Xinhua news agency.

The launch, which took place at the Taiyun Satellite Launch Center in northern China, was country’s 11th space launch this year and the seventh since July.

The Shijian VI-04 satellites will study the space environment during a nominal two-year mission, according to Xinhua.

A pair of Shijian satellites conducted an orbital rendezvous in mid-August, according to orbital analysts using U.S. Air Force tracking data.