Russia's Augur-RosAeroSystems will finish in 2011 the construction of a third large-size tethered aerostat under a contract with a Chinese firm, the company's president said.

The Puma aerostat is primarily designed to carry an early-warning radar station, but could also carry other surveillance and communications equipment, which makes it a low cost alternative to satellites.

"We are not worried about China copying our design because we are well-protected by our technologies and know-how," Gennady Verba told reporters on Saturday, adding that two aerostats had already been delivered to China.

The aerostat could climb to altitudes of up to 5,000 meters (16,400 feet) and stay in the air for 30-35 days without landing.

The payload is located on a truss, suspended under the envelope in a protective soft-pressurized cockpit of an aerodynamic shape.

RosAeroSystems is a leading Russian manufacturer of airships and aerostats. Foreign partners include Kubicek (Czech Republic), Voliris (France), and the U.S. companies Worldwide Aeros and General Aeronautics Corporation.