Self-Powered 1 mN Thruster for CubeSats

CubeSats are becoming more appealing for military applications due to continuing miniaturization of electronics, providing opportunities for distributed space assets and increased security through redundancy. In order for CubeSats to firmly establish relevance, however, they must be able to perform the same tasks as their larger counterparts, while keeping costs and deployment time low. Electrospray propulsion is a form of electric propulsion that uniquely suited for CubeSat operation due to the low power, high specific impulse, high efficiency, and low-pressure of the liquid propellant. These characteristics translate into exceptionally high dekta-V capabilities, enabling game-changing maneuverability and mobility. Busek will deliver a self-powered 1mN electrospray thruster that can deliver 200m/s delta-V to a 3kg CubeSat. Because of the heritage of this technology, the Phase I effort will focus on miniaturization of durable, reliable electronics as well as the propellant management system. Phase II funding would enable a space-qualified propulsion system. The resulting package can enable CubeSats to undertake a new class of mission: formation flying, plane changes, orbit changes, de-orbit and drag makeup. The flight unit will consume approximately 10W and 1.25U volume. BENEFIT: The result of additional funding will be a fully functional, self-powered electrospray thruster that fits within a 1.25U volume envelope. This power / propulsion module will impose no power burden on the host CubeSat, and can supply additional power to the main CubeSat bus. A larger prototype of this technology without electronics is being delivered to a government customer. Other initial customers are expected to be the AFRL and NRO. The near-future (end of 2009) is expected to witness the launch of the Colony program, the NRO effort to launch multiple CubeSats (~3L at 3kg) to reduce platform cost and gain heritage. If this vision is successful, CubeSats will be used increasingly by the warfighter in order to provide intelligence rapidly, effectively, and at a significantly reduced cost. A self-powered high delta-V propulsion module would enable these CubeSats to expand in versatility and relevance by enabling them to undertake new missions, ranging from formation flying, plane and altitude changes. Deorbiting space assets in a controlled manner, for example, is an increasing concern for space agencies. The propulsion system developed under this effort is small enough to be integrated into such a 3U CubeSat, and can effectively deorbit a CubeSat in an 800km circular orbit to an elliptical orbit with a 200km perigee in 57 days. This electrospray package is the only known technology that promises to make this possible in a controlled, reliable manner. Although deorbiting maneuvers are critical to sustainable operations in space, the high delta-V package enables other missions for these CubeSats. For example, CubeSat observation missions using a CCD can improve resolution for a given optics package by reducing the distance to the object being observed. To maintain a 300km circular orbit, such a propulsion system operated during 15% of the orbit could maintain orbit for at least 46 days. Further, the electrospray thruster can enable a 1.5 degree plane change in a 3kg CubeSat at 800km (11.5 days). These capabilities are uniquely provided (for the mass, volume, power requirements) by the deorbiter electrospray propulsion system, providing a significant advantage to any CubeSat in orbit, whether from military or corporate ownership.