Zhou Weijiang, a member of the National Committee of the Chinese People's Political Consultative Conference and a researcher at the 11th Academy of China Aerospace Science and Technology Corporation, revealed to Science and Technology Daily on the 10th that my country's Mars probe, which is scheduled to be launched in 2020, has completed its aerodynamic shape design, as well as its aerodynamic and aerothermal design.
It is understood that my country's Mars exploration mission aims to achieve its three major objectives—orbiting, landing, and roving—in a single mission. The landing process, in particular, involves several aerodynamic challenges.
Zhou Weijiang explained that the lander's initial descent speed is very high. To prevent it from burning up due to excessive heat generated by air friction, a certain amount of lift is needed to help it decelerate. For spacecraft with this type of axisymmetric structure, generating lift requires making it asymmetrical, and there are several methods to do this. Some probes at home and abroad adopt the strategy of adjusting the center of gravity, while my country's Mars lander generates lift by activating active control components in conjunction with jet control.
At the same time, controlling the attitude of the lander is very important; if it flips over, it may be burned or deviate from its trajectory.
Zhou Weijiang explained that during the lander's descent, components will continuously separate. For example, the front cover must be jettisoned first, and the parachute must be deployed; this process must not affect the spacecraft's stability. Upon reaching a certain altitude, the bottom cover must be jettisoned; since the lander is landing bottom-facing, this action is essentially performed against the wind. Next, the rover inside the capsule must be jettisoned. This results in several components landing together, and if they interfere with or collide with each other, it will significantly impact the mission. These issues must be thoroughly considered in the aerodynamic design.
He further explained that my country's Mars probe is relatively small, and its aerodynamic, aerothermal, and related operating system designs are subject to strict weight limitations. "For example, with heat shield materials, if too little is used, the lander will burn up; if too much is used, the weight will exceed the limit," he said. "Each system and structure must be carefully calculated, with every bit of margin being strictly controlled, leaving almost no room for error."
However, Zhou Weijiang stated that all aerodynamic design work for the Mars probe has been completed and is currently undergoing testing and verification.
