With 25 scienctific experiment racks, ion thruster, high efficiency solar array wing, 7 degree of freedom 10 m robotic arm, automatic speed rendezvous etc. newer technology allow the smaller CSS to carry out tasks comparable to the 400 ton ISS.
View of Tianhe core module from exterior camera.
CSS modules are designed to be highly integrated with the "1+1=1" concept. This high degree of integration allow efficient resource sharing, removing unnecessary redundancy, make possible because the CSS is designed by a single country.
SZ-13 docked with Tianhe core module, with TZ-2 in the background.
"1+1=1" as explained by chief designer Wang Suo, means that while each module is indepedent, when seamlessly integrated they function as if they're one single module.
Current CSS configuration with TZ-2 and TZ-3 docked at both end, SZ-13 docked underneath.
CSS is constructed in two phases. In 2021, the verification phase, and in 2022, orbital construction phase. Six mission related to CSS were launched in 2021, the maiden launch of CZ-5B with next-gen spacecraft, the CZ-5B launch of Tianhe core module, the launch of TZ-2, TZ-3 cargo spacecraft, and SZ-12, SZ-13 manned mission.
The end of SZ-13 mission will signify the completion of the verification phase. The four major tasks of the SZ-13 are to carry out two EVA, deploy robotic arm to test transposition of the TZ cargo spacecraft, and perform manual rendezvous. SZ-13 will return in mid Apr.
The fourth EVA carried out in SZ-13 mission, with Ye Guangfu on the robotic arm.
Robotic arm deployed to transpose the TZ-2 cargo spacecraft.
Manual rendezvous with radial docking, as seen from the view point of TZ-3 cargo spacecraft.
After the verification phase started in 2021 is completed, the orbital construction phase will commence with SZ-14 mission in 2022. The pace will pickup in the construction phase, with four launches TZ-4, SZ-14, Wentian (WT) space lab, Mengtian (MT) space lab, carry out successively within five months, an average of a launch every five weeks.
The WT space lab will be docked to the left as pointed by the blue arrow, and the MT space lab will be docked on the right, as pointed by the red arrow.
The addition of the two space labs will complete the CSS construction. Both space lab modules of the CSS are above 20 tons, diameter 4.2 m, length 17.9 m. The length of the space lab modules are longer than the 16.6 m of the Tianhe core module.
Each space lab module will approach the Tianhe core module from the front with solar array half extended, before being transposed to each side by the robotic arm.
Combined, with TZ cargo space craft and SZ space craft docked, the CSS will be a 100 ton class space station. The transposition of the space lab module is critical to the construction of the CSS, two transposition method are prepared. The plan A is to utilize the transposition robotic arm installed on the space lab module. This method is simple and reliable.
The space lab transposition robotic arm on each space lab will connect with the Tianhe utility node at the two interface highlighted.
The plan B to transpose the space lab is to utilize the 10 m robotic arm installed on the Tianhe core module, which is capable of handling a payload up to 25 tons. Although the procedure is simple with plan B, it require high precision to carry out. The transposition test carried out by the SZ-13 crew with the TZ-2 is the plan B.
