太阳与地磁活动对超低轨重力卫星电推进系统工作的影响

面向当前第25太阳活动周, 评估太阳与地磁活动对超低轨重力卫星电推进系统工作的影响。通过对超低轨道重力卫星进行轨道仿真和分析GOCE任务数据, 得出大气阻力的变化规律, 并获得了太阳活动极大年附近任务和极小年附近任务对携带工质量的影响、地磁暴对电推进系统保持"无拖曳"工作的影响。结果表明: 其余情况相同下, 卫星在太阳活动低年附近任务的工作轨道高度可较高年降低约20 km, 有利于提高重力信号强度。强地磁暴通常引起超低轨道卫星阻力增加30%~90%, 飞行控制需为克服地磁暴影响留足够的推力裕度。推力器设计应保证最大推力的10%~70%推力区间具有高比冲, 且着重考虑此区间的寿命问题。 

Influence of Solar and Geomagnetic Activities on Electrical Propulsion System of Ultra-Low Orbit Gravity Satellite

The influence of solar and geomagnetic activities on electrical propulsion system of ultra-low orbit gravity satellite was evaluated for the current 25th solar cycle. The orbit simulation was carried out and the data of GOCE mission was analyzed. The variation of atmospheric drag was analyzed. The influence of solar activity on propellant consumption and the influence of geomagnetic storm on drag-free operation were obtained. The results show that the orbit altitude of the satellite in the low solar activity years can be reduced by about 20 km compared with that in the high solar activity years, which is conducive to improving the gravity signal intensity. Strong geomagnetic storms usually increase the drag by 30% to 90% at ultra-low orbit, so thrust margin is required for geomagnetic storms. Designer should ensure high specific impulse in thrust range of 10% to 70% of the maximum thrust. The life consideration of this range is important.