China launched two disaster monitoring satellites Saturday as officials announced the country's next piloted space mission could occur before the end of September, state media reported.

The two remote sensing birds blasted off at 11:25 p.m. EDT Friday (0325 GMT Saturday). It was late morning Saturday at the Taiyuan launch site in northern China.

The two-stage Long March 2C rocket released the two satellites in a sun-synchronous orbit shortly after launch.

Expected to last more than three years, the satellites are the first disaster monitoring spacecraft orbited by China, according to the Xinhua News Agency.

Optical and infrared cameras can provide global coverage every two days, Xinhua reported.

The satellites will be used to guide recovery efforts after large-scale natural disasters, such as the deadly Sichuan earthquake that struck China in May.

China relied on commercial imagery from U.S. and European providers to aid early responders in the Sichuan earthquake.

Xinhua also reported Saturday that Shenzhou 7, China's third human spaceflight, will launch between Sept. 25 and 30, several weeks earlier than previously announced.

Three Chinese astronauts will launch atop a Long March 2F rocket from the Jiuquan space base in northwestern China.

One of the crew members will leave Shenzhou 7's crew compartment to venture outside in China's first spacewalk. Six military pilots have been selected for the mission, with three prime astronauts and three backup crew members, Xinhua reported.

The astronauts' identities have not yet been revealed.

Shenzhou 7 will come two years after China's most recent human spaceflight in October 2005. China became the third nation to launch a person into space during the Shenzhou 5 mission in 2003.

• Video - Life Inside the Jules Verne Space Cargo Ship
• Shenzhou Rising: China's Second Manned Spaceflight
• Special Report: Emerging China, Engaging China