Laser-pointing system could help tiny satellites transmit data to Earth

Phys.org  December 14, 2018
CubeSats struggle to efficiently transmit large amounts of data down to Earth due to power and size constraints. To fine-point its downlink beam, researchers at MIT utilize an uplink beacon signal captured by an on-board detector and tracked by an off-the-shelf MEMS fast steering mirror. As these miniature actuators lack feedback sensors, the system design is augmented with an optical calibration signal to provide the mirror’s pointing feedback. They developed calibration algorithms utilizing the feedback signal to achieve higher fidelity beam pointing control. Experimental results show that beacon tracking errors of only 16 μrad root-mean-square are feasible for both axes, significantly exceeding the mission pointing requirement of 0.65 mrad and indicating the feasibility of narrower beams and higher data throughputs for next-generation downlink demonstration missions…read more. Open Access TECHNICAL ARTICLE 

Apart from the structure, all the FPS-related optomechanical components are COTS, making the system a very low-cost solution. Credit: https://doi.org/10.1117/1.OE.58.4.041605