Orbital flight of CubeSats at altitudes between 150 and 250 km has the potential to enable a new class of scientific, commercial, and defense-related missions. A study is presented to demonstrate the feasibility of extending the orbital lifetime of a CubeSat in a 210 km orbit Propulsion consists of an electrospray thruster operating at 2W, 0.175 mN thrust, and an Isp of 500s. The mission consists of two phases. In Phase I the CubeSat is deployed from a 414 km orbit and uses the thruster to de-orbit to the target altitude of 210 km. In Phase II the propulsion system is used to extend the mission lifetime until propellant is fully expended. A control algorithm based on maintaining a target orbital energy is presented which uses an Extended Kalman Filter to generate estimates of the orbital dynamic state, which are periodically updated by GPS measurements. For Phase I, the spacecraft requires 25.21 days to descend from 414 to 210 km, corresponding to a ΔV = 96.25 m/s and a propellant consumption of 77.8 g. Phase II lasts 57.83 days, corresponding to a ΔV = 119.15 m/s during which the remaining 94.2 g of propellant are consumed.
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机译：CubeSats的轨道飞行在150至250 km的高度上具有实现新型科学，商业和国防相关任务的潜力。提出了一项研究，以证明延长CubeSat在210 km轨道上的轨道寿命的可行性。推进系统由一个工作在2W，推力为0.175 mN，Isp为500s的电喷雾推进器组成。任务分为两个阶段。在第一阶段中，CubeSat从414 km的轨道部署，并使用推进器将其解轨道至210 km的目标高度。在第二阶段中，推进系统用于延长任务寿命，直到推进剂完全耗尽。提出了一种基于维持目标轨道能量的控制算法，该算法使用扩展卡尔曼滤波器来生成轨道动态状态的估计值，该估计值会通过GPS测量值定期更新。对于第一阶段，该航天器需要25.21天才能从414下降到210 km，这相当于ΔV= 96.25 m / s和77.8 g的推进剂消耗。第二阶段持续57.83天，对应于ΔV= 119.15 m / s，在此期间消耗了剩余的94.2 g推进剂。
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