China is about to launch its second experimental space lab and another manned space mission
Advancing China's space program is a priority for Beijing, with President Xi Jinping calling for the country to establish itself as a space power, and apart from its civilian ambitions, Beijing has tested anti-satellite missiles.
China insists its space program is for peaceful purposes, but the U.S. Defense Department has highlighted its increasing space capabilities, saying it was pursuing activities aimed to prevent adversaries from using space-based assets in a crisis.
In a manned space mission in 2013, three Chinese astronauts spent 15 days in orbit and docked with an experimental space laboratory, the Tiangong 1, or "Heavenly Palace".
China will launch the Tiangong 2 just after 10 p.m. (0200 GMT) on Thursday, a space program spokeswoman told a news conference carried live from the remote launch site in Jiuquan, in the Gobi desert.
The Shenzhou 11 spacecraft, which will carry two astronauts and dock with Tiangong 2, will be launched sometime next month, mission spokeswoman Wu Ping said on Wednesday.
The astronauts expect to remain in Tiangong 2 for about one month, Wu added.
The launch, assuming it goes smoothly, will add a high-tech sheen to China's week-long National Day celebrations starting Oct. 1, as well as the shorter Mid-Autumn Festival holiday this week that coincides with the full moon.
China will launch a "core module" for its first space station some time around 2018, a senior official said in April, part of a plan for a permanent manned space station in service around 2022.
China has been moving to develop its space program for military, commercial and scientific purposes, but is still playing catch-up to established space powers the United States and Russia.
China's Jade Rabbit moon rover landed on the moon in late 2013 to great national fanfare, but soon began experiencing severe technical difficulties.
The Jade Rabbit and the Chang'e 3 probe that carried it there marked the first "soft landing" on the moon since 1976. Both the United States and the Soviet Union had accomplished the feat earlier.