Electric Solar Wind Sail Pole Sitter Spacecraft

太阳能风帆极电动航天器方案总结 传统航天器能力的一个主要限制是它们可以携带的燃料数量有限。弹道一般是弹道的，通过短推进器爆炸或重力助攻进行修改。然而，太阳是一个无限推力的来源，如果适当地利用它，可以允许航天器进行常规航天器不可能的操纵，例如完全离开黄道面的“轨道”。其中之一是利用动态和太阳力(由太阳光子通量或太阳等离子体通量--太阳风提供)来平衡太阳和地球的重力，以便航天器可以在地球两极之一上方的固定位置盘旋。这就是所谓的“政客”轨道。 为利用太阳风而设计的一种类型的航天器是电动帆航天器(e-sail)，它由一个中央集线器组成，从该集线器辐射一些(约80公里)长的绳索(约20公里)，所有绳索都充电到高正势，以便与太阳风的质子发生反应，提供推力。整个结构被旋转以提供陀螺刚度 策略者使用电子帆船的想法是一个令人兴奋的新研究领域，但具有非常实际的潜在应用。北方通信就是一个例子。纬度60度以上的地球静止卫星的通信价值有限，其结果是迄今认为解决办法是在高度偏心轨道上建立昂贵的航天器星座。最近的加拿大极地通信和天气(PCW)计划就是这种类型的，当它对两颗卫星的成本估计达到天文数字时，该计划被搁置了。另一方面，策划者可以作为通信卫星在极点上空盘旋，也可以从相对固定的地点监测天气。作为遥感平台，政客也有许多优势，但最重要的应用可能是监测太阳天气和警告地磁风暴。太阳耀斑和物质抛射的结果是，这些事件摧毁了卫星，扰乱了通信，摧毁了电网，造成了巨大的经济损失和生命威胁。Ace和SOHO航天器是目前我们监测太阳天气的最佳手段，它位于太阳-地球L1，为这些事件提供30到60分钟的预警。一个策略者可以停在这些航天器朝太阳方向的两倍远的地方，从而使我们在地球上的警告时间增加一倍。 这项研究的最终目的是进行电子帆坐杆飞行的技术示范飞行，但首先必须了解这种类型的航天器在这种轨道上的动力学和控制。这项提议的电子帆杆位以前从未被考虑过。 因此，这一提议的目标是：确定电子帆上的太阳等离子体推力的特征；调查电子帆极点轨道的稳定性和可控性；设计控制系统，使电子帆航天器在地球一极上方的某个固定点悬停；设计一种方法，保持电子帆航天器的结构完整性；以及研究一种激进的新技术--光子腔推进器，这将利用激光光压对电子帆进行结构控制。

Electric Solar Wind Sail Pole SItter Spacecraft Proposal Summary A major constraint on the capabilities of conventional spacecraft is the limited amount of fuel they can carry. Trajectories are generally ballistic with modifications by means of short thruster bursts or gravity assists. However, the Sun is a source of unlimited thrust which if appropriately harnessed can allow spacecraft to perform manoeuvres impossible for conventional spacecraft, such as "orbits" entirely out of the plane of the ecliptic. One of these balances the gravity of the Sun and the Earth with dynamic and solar forces, (provided by either the solar photon flux or the solar plasma flux - the solar wind) so that the spacecraft can hover in a fixed position above one of the Earth's poles. This is called a "polesitter" orbit. One type of spacecraft designed to use the solar wind is the electric sail spacecraft (e-sail) consisting of a central hub from which radiate a number (approx 80) of long tethers (approx 20 km) all charged to a high positive potential so as to react against the protons of the solar wind to provide thrust. The whole structure is spun to provide gyroscopic stiffness The idea of a polesitter using an e-sail is an exciting new research area which nevertheless has very practical potential applications. One example is northern communications. Above 60 degrees latitude geostationary satellites are of limited value for communications, with the result that expensive constellations of spacecraft in highly eccentric orbits have been seen as the solution thus far. The recent Canadian Polar Communications and Weather (PCW) program of exactly this type, was put on hold when its cost estimates for just two satellites became astronomical. A polesitter, on the other hand, could just hover above the pole as a communications relay satellite and could also monitor the weather from a relatively fixed point. A polesitter would also have many advantages as a remote sensing platform, but perhaps the most significant application would be for monitoring solar weather and warning of geomagnetic storms. The result of solar flares and mass ejections, these events destroy satellites, disrupt communications and knock out power grids at great financial cost and threat to lives. The Ace and SOHO spacecraft, currently our best means of solar weather monitoring, are at Sun-Earth L1, providing 30 to 60 minutes of warning of these events. A polesitter could be parked twice as far sunward as these spacecraft, thus doubling the warning time for us on the Earth. The ultimate objective of this research is a technology demonstration flight of an e-sail pole sitter, but it is necessary first to understand the dynamics and control of this type of spacecraft in such orbits. The e-sail pole sitter of this proposal has never before been considered. The goals of this proposal then are: to characterize the solar plasma thrust on an e-sail; to investigate stability and controllability of e-sail polesitter orbits; to design a control system to hover an e-sail spacecraft at a fixed point above one of the Earth's poles; to design a method to maintain the structural integrity of an e-sail spacecraft; and to investigate a radical new technology, the photonic cavity thruster, which would use laser light pressure for structural control of an e-sail.