On the evening of December 31, 2019, less than 5 hours before the arrival of 2020, the command and control hall of the Xi'an Satellite Measurement and Control Center was brightly lit. Song Chao is working with colleagues to implement the fourth mission of the 20th satellite. They sat in front of the computer and stared intently at the satellite status data on the big screen.
Four days ago, "Fat Five" carrying the practical XX satellite staged a "return of the king" at the Wenchang space launch site. The launch mission was a complete success, and the "Shepherds" were still afraid to take it lightly. "For us, completing the launch is only the first step," said senior engineer Zhu Yongjie. In their minds, accurately orbiting the satellite from the launch scheduled orbit to a geosynchronous orbit about 36,000 kilometers away from the earth, and completing the fixed point and opening the load are as important as completing the Fat Five launch mission. "This stage is like carefully caring for a newly born baby in the delivery room. The period before the satellite is successfully positioned to reach its best working condition is sleepless nights," said Zhu Yongjie.
In the orbital computer room, engineers Li Jinyuan and colleagues, as think tanks for carrying out orbit control missions, simulated a variety of methods before the launch to simulate more than 10 plans for the rocket to send satellites to different distant locations. What they have to do now is to calculate the most fuel-saving orbital strategy based on the current orbital state of the satellite, to ensure that the satellite can accurately complete the orbital change, and to extend the working life of the satellite as much as possible.
Li Jinyuan introduced that the satellite ’s super-synchronous earth orbit had a difference of more than 10 degrees between the ascending node and the apogee. For the first time, the Xi'an Satellite Measurement and Control Center implemented such an orbital change mission. How to put this 8-ton satellite into the target orbit under the most fuel-saving situation is the biggest test for them. Li Jinyuan has entered a 24-hour standby state. "My dormitory is only 5 minutes away from the computer room. Once the task is needed, I can come to deal with it as soon as possible," he said.
"The shutdown order was issued, the ignition was over, and the satellites were operating normally! Comrades, Happy New Year!" At 20:37, Song Chao called out the dispatch password. There was a warm applause in the command hall, and the festive "Congratulations on the successful completion of the fourth successful orbit control of the 20th satellite" was spread over the entire large screen.