China is expected to launch the second module for its Tiangong space station on Sunday (July 24) from Wenchang spaceport in south China.
The Wentian module will launch on board the huge Long March 5B rocket and should join up with the Chinese space station's Tianhe core module hours later, expanding the country's crewed space research facility.
China generally does not announce launch times ahead of time, nor does it broadcast most of its launches live. Spaceflight Now suggests the rocket will launch around 2:15 a.m. EDT (0615 GMT or 2:15 p.m. local time) based on airspace warning notices. Chinese state media will likely provide mission updates later in the day.
Tiangong is currently hosting three Shenzhou 14 taikonauts who have been on board the Tianhe module for about six weeks, since launching to space on June 5.
Related: The latest news about China's space program
Wentian is both a science module and an area to expand the living space aboard the small space station. It includes experiment cabinets for performing science work, along with more astronaut sleeping quarters to allow crew handovers. Once the module is ready, Tiangong will be able to host temporarily as many as six crew members.
The 174-foot (53-meter tall) Long March 5B is a Chinese heavy-lift rocket variant designed to launch China's space station modules, which each have a mass of about 48,500 pounds (22,000 kg).
The megarocket's first launch in 2020 sent a prototype new-generation crew spacecraft into low Earth orbit, while the second in 2021 launched Tianhe. On both occasions, the rockets' massive core stages made high-profile, uncontrolled reentries causing worries among space debris trackers, although both deorbited without incident.
Wentian's task post-launch will be to rendezvous with Tianhe, currently orbiting at 236 miles (381 kilometers) above Earth, and mate with Tianhe's forward docking port. Next, it will be moved to a lateral or side port using the module's 33-foot (10-meter) long robotic arm.
China is planning to launch another module later this year to bring more experiments to orbit. The module, called Mengtian, is scheduled to launch in October. Wentian and Mengtian together will create a T-shaped space station that China plans to operate for at least a decade.
The country tends to operate independently in space, and NASA is not allowed to "engage in any bilateral activities with China or Chinese-owned companies," according to the agency. Agency officials did express extreme displeasure with China's uncontrolled fall of the Long March 5B core stage in 2021, and the Biden administration has criticized China's space activities a few times recently.
Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom or Facebook.
Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.
