Laboratory Cabin Module
The Laboratory Cabin Module (LCM) () is a modular component of the Tiangong space station. Based on the Tiangong-2 experimental space module, the LCMs complete the third and final stage of Project 921, the CNSA's program to establish a permanent Chinese space station. While China's small unmanned spacecraft can provide platforms for zero gravity and exposure to space for scientific research, the LCMs offer a long term environment combined with ready access by human researchers over periods that far exceed the capabilities of Shenzhou spacecraft. Operations will be controlled from the Beijing Aerospace Command and Control  Center in China. The first two LCMs scheduled to launch are Wentian in 24 July 2022 and Mengtian () around October 2022. Purpose. The first laboratory module will provide additional navigation avionics, propulsion and orientation control as backup functions for the Tianhe Core Module (TCM). Both LCMs provide 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 the LCMs will be fitted with rendezvous equipment and will first dock to the axial port of the CCM. A mechanical arm similar to the Russian Lyappa arm used on the Mir space station will then move the module to a radial port of the CCM. Electrical power is provided by two steerable solar power arrays, which use photovoltaic cells to convert sunlight into electricity. Energy is stored to power the station when it passes into the Earth's shadow. Resupply ships will replenish fuel for LCM 1 for station-keeping, to counter the effects of atmospheric drag. Dimensions . The length of each module is 17.9 m. They are cylindrical with a maximum diameter of 4.2 m and an on-orbit mass of approximately apiece. Launch. Both modules are due for launch in 2022 on Long March 5B launch vehicles from Wenchang Satellite Launch Center. "Wentian" is scheduled to launch in 24 July 2022, while "Mengtian" is scheduled to launch in October. They will be inserted into a low Earth orbit with an average altitude of at an orbital inclination of 42 degrees, centered in the Earth's thermosphere.