Low Power LEDs for CubeSat Attitude Estimation and VLC during proximity operations

As CubeSats continue to gain prominence in the modern space industry due to their cost-effectiveness compared to traditional satellites, the number of CubeSats in orbit is poised for exponential growth. This proliferation creates a pressing need for enhanced traffic management and coordination in space. Our proposed solution involves equipping CubeSats with LEDs on their surfaces, enabling the implementation of a system for visual light communication (VLC) and attitude estimation. This innovative approach could establish a universal communication network among CubeSats, significantly benefiting proximity operations and space situational awareness. Attitude estimation, a challenging task involving the determination of the relative orientation and position of one Spacecraft with respect to another, plays a pivotal role in various space applications such as space rendezvous, docking, formation flying, and satellite servicing. Optical, radar, and radio-based techniques are employed for relative attitude estimation. Optical methods, for instance, rely on cameras to visually observe other Spacecraft, utilizing computer vision algorithms to extract critical information regarding their position and orientation. However, optical sensors are susceptible to environmental factors like sunlight and shadows, and the absence of standardized CubeSat appearances poses challenges to accurate attitude estimation, potentially leading to measurement errors. Additionally, due to the small size of CubeSats, ground-based optical observations are inadequate for identifying and tracking them in space. A promising technology within CubeSat engineering is the utilization of LEDs for VLC, a technique that has already demonstrated success in high-speed inter-satellite communication, exemplified by the Starlink satellite constellation. The advantages of VLC include enhanced security and reliability compared to radio communication, immunity to RF interference, and more straightforward regulatory requirements. To implement this, low-power LED lights could be integrated into CubeSat exteriors to aid in target identification and attitude estimation in conjunction with VLC for proximity operations. A proposed standardized “Lighting Module” add-on, occupying less than 0.25U in volume and mass, could be attached to CubeSat exteriors, enabling identification and tracking from ground- and space-based observations. This innovative approach affects low Earth Orbit and Deep Space small satellite missions’ cost, power, mass, volume, and technology readiness. The identification and tracking process would involve CubeSats utilizing onboard cameras to locate LED lights, interpret their colors using computer vision, and determine the relative positioning of LEDs to estimate orientations accurately. A tracking algorithm would enable the calculation of CubeSat rotation over time intervals. To validate the feasibility of these technologies, the SWORD (Spacecraft Workings and On-orbit Robotics using Drones) facility, designed to simulate various space environments, would be employed for hardware testing. This testing would evaluate the tracking software’s performance under different conditions, including dark, ideal environments, lit non-ideal environments, and simulated on-orbit noise sources, focusing on swarm management applications. Integrating orientation recognition and VLC into a unified system for CubeSats offers a minimal yet universal solution for inter-satellite communication and docking assistance, potentially revolutionizing space traffic management and coordination.