China's Shenzhou 18 astronauts prep for 2nd spacewalk (video)

China's Shenzhou 18 astronauts are getting ready for a new extravehicular activity outside the Tiangong space station.

The upcoming activities and training include science experiments and orbital maneuvers, according to state broadcaster China Central Television (CCTV).

Commander Ye Guangfu and crewmates Li Cong and Li Guangsu have been aboard Tiangong since April 25 .

The trio have been using advanced remote-control systems for rendezvous and docking operations on in-orbit training systems and metacognitive training systems. They have also been practicing skills such as recognizing images, manual docking, remote docking and safe undocking of the spacecraft under different initial conditions. Ye and Li Guangsu completed a national-record spacewalk on May 28.

China's human spaceflight agency confirmed on Tuesday (July 2) that the spacewalk would take place in the near future. Often, the spacewalk will follow the day after such announcements.

The Shenzhou 18 crew have also undergone exercise-based cardiopulmonary function tests. The tests assess the cardiovascular and respiratory capabilities needed for upcoming spacewalks, using methods to simulate exercise-induced metabolic demands, according to CCTV.

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Meanwhile, science activities have been continuing aboard the station. Ye, Li and Li conducted maintenance of the combustion science laboratory cabinet by replacing burners, vacuuming and exhausting and organizing related materials, CCTV reported. The crew also replaced samples in the fluid physics laboratory cabinet, which is used to conduct on-orbit microgravity experiments on kinetic and other processes, including the behavior of different fluid systems.

The astronauts are now just over one-third of the way through their six-month stay aboard Tiangong. They will be joined in orbit by the Shenzhou 19 crew around October or November. Ye and crew will then hand over the station to the incoming astronauts and prepare to return to Earth .

China plans to operate Tiangong for at least a decade.