Spacecraft formation flying using Coulomb forces is a relatively new technology for spacecraft control and may have application for a wide variety of mission objectives including attitude control, collision avoidance, and orbit perturbation correction. Coulomb-controlled formations appear ideally suited for close formation-flying in high Earth orbits to perform wide field of view imaging missions using separated spacecraft interferometry. This paper discusses the challenges and prospects of developing spacecraft formations utilizing Coulomb forces. Formation flying on the order of tens of meters is very difficult using conventional ion propulsion methods, because the exhaust plumes will quickly interfere with the delicate on-board sensors. The Coulomb forces would allow the relative motion of satellites to be controlled without such contanimations. Since the rise time of the spacecraft charging is on the order of milliseconds, very high bandwidth control is feasible. Further, the fuel efficiency of the control makes very long duration missions possible. Non-Keplerian steady-state orbits are discussed which could be used to generate in-plane or three-dimensional static spacecraft formations. The currently examined static solutions are unstable and require the development of a control strategy. Further, the behavior of a two-satellite Coulomb formation with constant equal or opposite charges is discussed at GEO. A nonlinear, orbit elements-based feedback law is then introduced to control the relative motion within a two-satellite formation by stabilizing the orbit element differences about desired values. Global stability is analytically shown and illustrated through a numerical example. Asymptotic stability is proven for a semimajor axis only control about a circular orbit. The lack of general asymptotic stability with inter-spacecraft Coulomb forces is discussed.

中文翻译：

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库仑航天器编队控制的挑战与前景

利用库仑力飞行的航天器编队飞行是一种相对较新的航天器控制技术，可能已应用于多种任务目标，包括姿态控制，避免碰撞和轨道扰动校正。库仑控制的编队似乎非常适合在高地球轨道上近距离编队飞行，以使用分离的航天器干涉仪执行宽视场成像任务。本文讨论了利用库仑力发展航天器编队的挑战和前景。使用传统的离子推进方法很难在几十米的数量级上飞行，因为排气羽流会迅速干扰精密的车载传感器。库仑力将允许控制卫星的相对运动，而无需进行这样的限制。由于航天器充电的上升时间约为毫秒，因此非常高的带宽控制是可行的。此外，控制装置的燃油效率使长时间任务成为可能。讨论了非开普勒稳态轨道，该轨道可用于产生平面或三维静态航天器编队。当前检查的静态解决方案是不稳定的，需要开发控制策略。此外，在GEO上还讨论了具有恒定等电荷或相反电荷的两卫星库仑地层的行为。然后引入基于轨道元素的非线性反馈定律，以通过稳定关于期望值的轨道元素差异来控制两颗卫星编队内的相对运动。通过数值示例对全局稳定性进行了分析显示和说明。对于仅绕圆形轨道控制的半长轴，已证明渐近稳定性。讨论了航天器间库仑力缺乏一般渐近稳定性的问题。