电动绳系在低极轨卫星中的应用研究

低极轨卫星具有轨道周期短、对地观测分辨率高等优点,但由于所在轨道大气阻力大,其使用寿命受到较大限制。文章提出采用水平结构电动绳系抵消低极轨卫星大气阻力的方法,通过系绳电流与地球磁场相互作用产生洛仑兹力进行推进,进而在无燃料消耗的情况下实现对低极轨卫星轨道高度的维持。初步分析了该方法在低极轨不同尺寸卫星中的应用潜力,计算了160、400和800 km典型高度低极轨卫星所经历的地球磁场、电离层和高层大气环境相关参数变化,比较了不同条件下电动绳系推力与大气阻力大小随轨道位置的变化。分析结果表明,该方法适用于400 km轨道高度以上大卫星;在满足一定系绳长度和轨道高度的条件下,电动绳系可以有效延长低极轨卫星的轨道寿命。

Applications of electrodynamic tether in low altitude polar orbit satellites

The low altitude polar orbit satellite has the advantages of short orbital period and high resolution observation on the ground. However, the high atmosphere drag force shortens its orbital life, which restricts its applications. In this paper, we propose to increase the low polar satellite''s orbital lifetime by using a horizontal direction electrodynamic tether. We analyze the possibility of its application in low polar orbit satellites with different sizes at three typical altitudes (160 km, 400 km and 800 km). The magnetic field strength, the electron density and the atmosphere density are calculated by tracking the satellite''s motion. By comparing the tether''s Lorenz forces and the satellite''s atmospheric drag forces, it is shown that the horizontal direction electrodynamic tether can increase the orbital lifetime for low polar orbit satellites within a limit of the tether length, the orbit altitude and the satellite''s size, and is especially suitable for large satellites at the altitude above 400 km.