Concept
Wentian (), officially the Wentian laboratory cabin module (), is a major module of the Tiangong space station. It is the first Laboratory Cabin Module launched, and the first module to extend the existing Tianhe core module of the station. It was launched into orbit from the Wenchang Spacecraft Launch Site on 24 July 2022, successfully docking with Tianhe forward port at 19:13 UTC on the same day. On 25 July 2022 at 02:03 UTC, the crew of Shenzhou 14 opened the hatch and entered the module for the first time. Wentian was later relocated to the starboard port on 30 September 2022 at 04:44 UTC by the indexing robot arm to make way for the Mengtian module. The Wentian laboratory module provides additional navigation avionics, propulsion and orientation control as backup functions for the Tianhe Core Module (TCM). It also provides a pressurized environment for researchers to conduct science experiments in freefall or zero gravity which could not be conducted on Earth for more than a few minutes. Experiments can also be placed on the outside of the modules, for exposure to the space environment, cosmic rays, vacuum, and solar winds. The axial port of Wentian is fitted with rendezvous equipment and first docked to the axial port of Tianhe. A mechanical arm dubbed, as Indexing robotic arm, looking as a sort of Lyappa arm used on the Mir space station moved the module to a starboard port of the TCM on 30 September 2022. It is different from the Lyappa as it works on a different mechanism. Mir's Lyappa arm is needed to control the pitch of the spacecraft and redocking in a different plane, but the Wentian indexing robot arm is used when docking is needed in the same plane. In addition to this arm used for docking relocation, the Chinarm on Tianhe module, could also had been used as a backup of the indexing robot arm. In addition to this, it also carried a small long robotic arm like the Chinarm as a supplemental to that arm. It is used for manipulating extravehicular payloads and assisting EVAs.
