Duration: 6 months
The exponential growth of small satellite launches led to a paradigm shift in the space economy, justified by their reduced cost and development time. However, several challenges, such as the reduced pointing performance, restrain wider employment of SmallSats. Due to the low inertia and limited performance of the Attitude & Orbit Control System (AOCS), SmallSats are constrained by an intrinsic limit in the pointing accuracy, far from the arcsec-level precision required by several missions and only reached by larger platforms. This research investigates a dual-stage pointing control architecture to push the pointing accuracy down to a few arcsec. This way, high-precision pointing and thus high-quality data can be achieved from low-cost platforms. The proposed system enhances the performance of the traditional AOCS by including a second control loop named High-Precision Pointing Platform (HPPP), correcting for the AOCS high-frequency residual pointing error and jitter. Complementary to the AOCS, which controls the entire spacecraft attitude, the HPPP acts directly on the payload line of sight via active optical elements such as a Fine Steering Mirror. This leads to faster and more accurate control, crucial when dealing with jitter. Thanks to dedicated sensors, the HPPP provides a finer estimation of the pointing error, with benefits in the performance of the overall control loop. Effective communication and interaction between AOCS and HPPP can provide an even larger improvement in the system performance, paving the way for uncharted optimization. Applications for the proposed technology include astronomy, Earth Observation and laser communication. In-orbit demonstration of the HPPP will occur with the ESA CubeSpec mission. This CubeSat carries out spectroscopical analysis of stars from an inexpensive and miniaturized platform. The required arcsec-level pointing accuracy cannot be met with a standard AOCS, making the dual-stage approach an effective solution.
