The advent of radio occultation (RO) instruments aboard CubeSats leads to the possibility of a mission to sound atmospheric internal gravity waves if such satellites are deployed in close-flying constellation. The satellites in the constellation must have slightly perturbed orbital inclinations in order to spread the RO soundings within clusters in two horizontal dimensions, and consequently the satellites will disperse because they will experience different rates of regression of nodes. This dispersion must be countered by propulsive maneuvering in order to maintain the close formation of the constellation. Here, a theoretical approach to the necessary propulsive maneuvering is presented and simulations using comprehensive orbit propagators are performed to analyze four propulsive systems: two cold gas propulsion systems and two electrospray propulsion systems. Cold gas propulsion permits greater separations in inclination between satellites in a constellation by virtue of the greater thrust they can exert on a spacecraft: cold gas propulsion can permit inclination separations of 1 to 10$^\circ$ while electrospray limits separations to less than 0.2$^\circ$. On the other hand, electrospray propulsion provides much longer mission lifetime by virtue of the greater total thrust it offers: cold gas propulsion expends all of its fuel in maintaining the constellation formation in less than approximately 100 days while electrospray propulsion can maintain formation for greater than 1000 days before expending all of its fuel. Mission lifetime is the most critical consideration for a mission, thus electrospray propulsion is recommended for the constellation-flying of CubeSats, but the accelerations that they offer must be greatly increased to enable spacecraft separations useful for tomography of internal gravity waves. Note that any close-flying constellation involving satellites with slightly perturbed inclinations will experience the same dispersing effect as the constellations described herein and, thus, require the same propulsive maneuvering to maintain formation.

中文翻译：

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用于内部重力波层析成像的立方体卫星星座的轨道维持

CubeSats 上无线电掩星 (RO) 仪器的出现，如果将此类卫星部署在近距离飞行的星座中，则有可能执行探测大气内部重力波的任务。星座中的卫星必须具有轻微扰动的轨道倾角，以便在两个水平维度的集群内传播 RO 探测，因此卫星将分散，因为它们将经历不同的节点回归率。必须通过推进机动来抵消这种分散，以保持星座的紧密形成。在这里，提出了必要的推进机动的理论方法，并使用综合轨道传播器进行了模拟，以分析四个推进系统：两个冷气推进系统和两个电喷雾推进系统。冷气推进允许星座中卫星之间更大的倾角分离，因为它们可以对航天器施加更大的推力：冷气推进可以允许 1 到 10$^\circ$ 的倾角间隔，而电喷雾将间隔限制为小于 0.2 $^\circ$。另一方面，电喷雾推进由于其提供更大的总推力而提供更长的任务寿命：冷气推进在不到大约 100 天的时间内消耗其所有燃料来维持星座形成，而电喷雾推进可以维持形成超过1000 天，然后耗尽所有燃料。任务生命周期是任务最关键的考虑因素，因此，建议将电喷雾推进用于立方体卫星的星座飞行，但它们提供的加速度必须大大增加，以使航天器分离可用于内部重力波的断层扫描。请注意，任何包含倾角轻微扰动的卫星的近距离飞行星座都将经历与此处描述的星座相同的分散效应，因此需要相同的推进机动来保持编队。