磁阻尼对火星探测器降落过程的动力学效应

Dynamics of magnetic resistance during Mars descent

火星稀薄的大气使得探测器再入火星时难以获得足够的减速阻力,为此,文章提出利用磁阻尼增加阻力的概念。高速再入的探测器与火星大气剧烈摩擦产生等离子体,利用探测器上的磁偶极场将等离子体捕获,同时在火星大气中形成一个"磁泡"区域并跟随探测器。由"磁泡"束缚的等离子体与来流的中性气体发生碰撞获得动量,又通过磁场作用将动量传递给探测器,从而使探测器获得一定的减速阻力。在磁阻尼的作用下,在同样的开伞高度探测器速度可降至更低,而低速开伞又可提高阻力伞打开的可靠性。因此,磁阻尼不仅可加快降低再入速度,而且还有助于提高探测器着陆火星的安全性。

It is difficult to decelerate in a descent on the Mars because of the thin atmosphere there. This paper proposes an idea of supplying the spacecraft with extra magnetic resistance. Plasma would be generated in the fierce friction between the high-speed craft and the atmosphere, and the plasma would be captured by the magnetic dipole field added to the craft. As a result, there is a magnetic bubble generated, which moves along with the craft. The exchange of momentum between the neutral airflow and the plasma generates a drag, which helps slow down the craft. With the help of the magnetic resistance, the craft achieves a lower Mach number at the same altitude. The reliability of the parachute deployment will be enhanced under a low velocity. As a result, the magnetic resistance may provide a great help to the security of Entry, Descent, and Landing（ EDL） on the Mars.