The Mengtian lab module docked with the front port of the Tianhe core module at 4:27 a.m. Tuesday after launching into orbit. Photo: Courtesy of China Manned Space Engineering Office

Mengtian measures about 17.9 meters in length and 4.2 meters in diameter and weighs about 23 tons. Its pressurized interior space has around 110 cubic meters, including an activity space of some 32 cubic meters for astronauts. Photo: Courtesy of China Manned Space Engineering Office

Shenzhou-14 crew members monitor the Mengtian module’s docking process in the Tianhe core module. The whole rendezvous and docking process took approximately 13 hours. Photo: Courtesy of China Manned Space Engineering Office

At the end of September, China moved the existing Wentian lab module to a side port of the Tianhe core module to vacate the front docking port for Mengtian’s berthing. Photo: Courtesy of China Manned Space Engineering Office

Shenzhou-14 astronauts Chen Dong (right) and Cai Xuzhe carried out the second extravehicular activity on Sept. 17. Photo: Courtesy of China Manned Space Engineering Office

Cai (front) and Chen installed additional equipment to the space station and carried out an extravehicular rescue for the first time during the spacewalk. Photo: Courtesy of China Manned Space Engineering Office

Cai exited the cabin first. He stayed inside the core module during the Shenzhou-14 crew members’ first spacewalk. The two astronauts took five hours to complete their extravehicular activities. Photo: Courtesy of China Manned Space Engineering Office

A photo by Shenzhou-14 crew member Liu Yang shows the Tibet autonomous region from space. Liu, Cai and Chen are expected to return to Earth next month. Photo: Courtesy of China Manned Space Engineering Office