​“北京明白！”航天员在太空漫步时，地面工作人员为什么重复这句话？

During the past two years, mission controllers at the center, which is located inside the strictly guarded Beijing Aerospace City compound in a northwestern suburb of the capital, have often appeared on television monitoring spacecraft operations, calculating trajectories, uploading commands and conversing with astronauts.

The controllers, in aquamarine uniforms with the "China Space" logo on the back, were attentive, energetic and sharp-eyed on TV.

Behind that glamorous appearance, though, the work of these men and women is demanding, challenging and painstaking.

A nonstop flow of information related to trajectories and positions pours into the windowless control halls 24 hours a day from orbiting spacecraft and telemetry stations across the country, as well as tracking ships on the oceans. The controllers monitor the data with rapt attention, make quick decisions on the measures to take in the event of alarms about in-orbit malfunctions or emergencies, and produce specific plans for the next step of each mission.

“Our controllers on the Tiangong space station program work 12-hour shifts that start at 8 am or 8 pm. Their job requires them to be utterly focused on information that changes in a matter of minutes or even seconds. Actually, they spend much longer than 12 hours here every day because they need to attend briefings before and after their shifts, and also often need to participate in workshops on mission details,” Hu Guolin, head of the controllers in charge of long-term spacecraft operations, said during a recent media tour of the center.

“It is not unusual that we have to move our space station higher or lower than its normal altitude to avoid incoming hazardous debris — and that is never easy. Adjusting a spacecraft's position is not as simple as just typing some codes and sending them out, as some people may imagine. It requires systemic considerations: you must decide which tracking station or ship will upload the commands and monitor the spacecraft during the process; you need to pick another station or ship as backup; you also need to take a host of factors into account, including the orbital adjustment's impact on the space station's condition, like its power generation and the operation of internal equipment.”

The controllers must have clear, sharp minds and be quick and decisive to figure out solutions to potential risks.

All the efforts have one ultimate goal, which is to guarantee the astronauts’ safety and the long-term, smooth operation of the space station.

“Our task is to make the astronauts feel safe and comfortable, and let them know that they have our full support and that of the entire nation so they can do their jobs in a happy mood.”

“It has been their support that always makes us feel good inside the space station,” Wang Yaping said.