Yuanwang No.3 escorts Chang’e through the black barrier and successfully completes the task of maritime TT & C

On the early morning of December 17, the chang’e-5 spacecraft returned to Beijing, and yuanwang-3, a ship affiliated to China Satellite maritime TT & C department, escorted it in the deep Indian Ocean. < p > < p > in this mission, yuanwang-3 is the only maritime TT & C force, which needs to complete the telemetry, external measurement and optical measurement tasks near the black barrier of the first reentry. Zhang Wei, chief dispatcher of Yuanwang No.3 ship, introduced: “in the mission, the S-band unified measurement and control equipment of Yuanwang No.3 ship sends out the attitude adjustment command for the first time within a short 100 second window before the returner enters the black barrier; the photoelectric theodolite undertakes the optical tracking task of the returner and provides the flight image information of the returner; the monopulse radar is mainly responsible for the external measurement task of the returner in the black barrier area, providing reliable data for the whole area It is the first stick of the reentry relay measurement and control, and also an important part of the whole measurement and control support system. ” < / P > < p > it is understood that the returner can only capture and track through shipborne monopulse radar and photoelectric theodolite in the black barrier, which seems to take only three minutes, but the difficulty of measurement and control is beyond imagination. < p > < p > in view of the complex TT & C process, Wang Erjian, engineer of the general technology office of China Satellite maritime TT & C department, explained: “the optical tracking equipment is like using the naked eye to look for a meteor flying at high speed in the sky through a telescope. The target flies very fast and it is very difficult to capture. The monopulse radar on the ship has a narrow search beam, and there is no earth earth response signal on the returner. The radar needs to use the reflected signal of the plasma shell for tracking. The surface of the plasma shell is very irregular, and the reflected signal fluctuates greatly. All these bring great challenges to the target search, acquisition and stable tracking. Our scientific and technological personnel successfully complete all the steps under pressure And contributed to the success of the mission. ”