China's land-based tracking telemetry and comm (TT and C and) network is fully prepared for the upcoming Shenzhou-21 crewed mission, set to ensure a smooth liftoff of the manned spaceship and safe trip of astronauts to the space station. As one of the seven major subsystems of China's crewed space program, the TT and C system serves as the only communication link between spacecraft and ground control after the aircraft's liftoff. The TT and C network that is composed of TT and C stations plays a vital role during the rocket's ascent phase thanks to its high reliability, precision, real-time performance, and data rate.
"After the launch, we mainly rely on TT and C stations along the rocket's flight path, including Dongfeng, Weinan, and Qingdao, to provide TT and C support. It's like a relay race, with each station passing the baton to ensure smooth liftoff and orbital insertion. Once the spacecraft enters orbit, TT and C support is primarily provided through the Tianlian relay satellites. Land-based tracking equipment and relay satellites complement each other, forming an integrated space-ground network that ensures the astronauts' safety throughout their journey," said Yan Yuan, an engineer with the Xi'an Satellite Control Center.
Located on the shores of the Yellow Sea, the Qingdao TT and C station will soon support the launch of Shenzhou-21. During the mission, engineers of the station will be responsible for sending remote control commands during the rocket-spacecraft separation phase, receiving telemetry data, and preparing key safety instructions. It will be the final baton in the land-based TT and C relay during the launch process.
"The combination of rocket and aircraft flies almost directly over us. We have to rotate antenna by nearly 180 degrees within just a few seconds as the target passes overhead. Then, in the following dozen seconds, we must quickly reacquire the target and issue critical commands," said Zhao Guohua, an engineer at the Qingdao TT and C station of Xi'an Satellite Control Center.
To this end, engineers have developed and rehearsed over a dozen operational plans. Through repeated drills, they have perfectly resolved the potential issues and risks during launch, ensuring that each crew can reach the space station safely.
"The Qingdao TT and C station was established for China's space program. As we shoulder bigger responsibilities, as our teams expand and the number of equipment grows, we'll continue to refine our TT and C models and innovate new methods to provide solid support for every Shenzhou crewed mission," said Zhao.
Land-based tracking telemetry, command network ready to support Shenzhou-21 mission
