And big reconnaissance satellites? No specifications are available from the U.S. National Reconnaissance Office, let alone the General Armaments Department, but the Delta IV Heavy launcher, which is used for such missions, can throw 13 tons to geosynchronous transfer orbit or 23 tons to low Earth orbit (LEO). The largest version of the Long March 5 is designed to lift 25 tons to LEO.

Official drawings show that the Chinese space station's modules will be broader than the cargo craft; quite possibly they will have the Long March 5's 5-meter diameter and therefore use much of its precision manufacturing equipment. That may be one reason the facility is being built in Tianjin. Another reason, as in the Long March 5 program, may have been the port city's access to sea transport to the new launch base under construction on the southern island of Hainan.

The 100,000-sq.-meter (1.08 million-sq.-ft.) spacecraft assembly plant will be substantially complete this August but not ready to begin operations until a year later. It is supposed to satisfy requirements for the next 15-20 years. Since the first Long March 5 is due to fly next year, the factory construction has clearly been timed to fit with the availability of the new launch capability.

The plant's test facilities will attend to the thermodynamic and mechanical properties of spacecraft, their electrical leaks and electromagnetic compatibility, state media report.

CAST has invested in building the factory. As is common elsewhere in the Chinese aerospace and commercial aviation industry, the local government is probably putting up quite a lot of the money. A defense budget contribution is also possible. CAST is a part of national space industry group CASC, which comes under the bureau responsible for defense science and technology industries.

CASC says has averaged 14 launches annually for the past five years and will make 16 this year, lofting 20 spacecraft. They will include the Shenzhou 10 mission, which will complete docking trials China is undertaking in advance of building the space station, and Chang'e 3, which will deploy a lander and rover in a soft landing on Moon. But for the remainder of the decade the launch rate will soar to an average of 30 a year, which CASC reckons will account for about 30% of the global total. By 2020, China will have more than 200 satellites in orbit, about 20% of the total.