With both the Shenzhou-15 crew and Shenzhou-14 crew working aboard China's nearly completed three-module space station, in-orbit rotations are set to become a norm, according to the China Aerospace Technology and Science Corporation(CASC) on Wednesday. 

The two crews, totaling half a dozen people, will live together at the station for about five days with many tasks lying ahead, and face-to-face information exchange is expected to be more efficient than previous remote chats.

"In-orbit rotation will become a pattern from now on as the station now has the capacity," a space station system designer told China Media Group.

Jin Jian, the deputy chief designer of the space station systems from the Fifth Academy at CASC, said a hands-on work handover is more direct and convenient.

According to Jin, apart from the renewal of consumables and supplies storage, the former crew will also guide the newcomers through the operating instructions for each piece of equipment, such as those for daily living, life support and experiment cabinets in particular.

"Consumables, such as air and water purifiers, need to be replaced with new ones every several weeks or months, just like those we use on Earth," Jin said.

He added that some scientific experiments require constant care, and therefore, some changes in parameters or swapping payloads need to be addressed in person. 

The two crews will also finish unpacking and setting up equipment in the second lab module, Mengtian. A directional camera, a gimbal camera, an emergency lamp and interior boards are among the items to be installed alongside the restoration of some sensors.

Before the Shenzhou-14 crew leaves the station for home, they'll have to clean up after themselves, set up the spaceship for departure, confirm the cargo storage and conduct other checks with the ground team.

A challenge for the station's life support system

Providing breathable air for six people aboard the China Space Station presents new challenges for the station's life support system.

According to Jin, the station's regenerative life support system has been designed to host six people, turning their exhaled carbon dioxide and released urine into oxygen and water.

"It is now set to a mode for six people, but the standard for temperature and humidity at the station remains the same," Jin said. 

"We've had enough tests on the ground and we are confident that the systems can function well in space and fulfill the needs of theirs."

The systems can achieve 100 percent oxygen regeneration and recover about 80 percent of the water resources inside the station, saving up to six tonnes of cargo supply.