LEDSAT: In-orbit demonstration mission for LED-based cluster launch early identification and improved LEO surveillance

The increasing number of small satellite cluster launches leads to a greater risk of confusion and collision soon after their deployment in orbit. In particular, the possibility to identify each CubeSat and to monitor their trajectories with passive optical methods could allow mitigating the possibilities of impacts among them. Thus, several researches in this field are currently on-going to improve the capabilities in space surveillance for satellite early identification. To this purpose, the LED-based small SATellite (LEDSAT) mission aims at testing the performances of a technology based on Light Emitting Diodes (LEDs) on-board the spacecraft able to autonomously illuminate the spacecraft and to allow ground-based telescopes to observe the CubeSat for a longer time window when the station is in darkness. The idea has been conceived and designed by an Italian student team from University of Rome “La Sapienza”, in cooperation with the Astronomy Department of University of Michigan (Unites States). This project is part of the educational activity carried on at the Sapienza Space Systems and Space Surveillance Laboratory (S5Lab) and LEDSAT has been selected for the 2ndedition of the ESA Fly Your Satellite (FYS) programme 2017. The on-board payload will operate in orbit by flashing with different patterns in order to simplify the possibility to distinguish different objects by minimizing the confusion between them. In addition, the on-board payload will allow testing different LED-based techniques for the nanosatellite tracking, attitude reconstruction and for the communication with ground in case of the Telemetry, Tracking, and Command (TT&C) subsystem failure. The design and the main features of this CubeSat have been defined to allow its detection by analysing the optical measurements collected during night-time by the observatories involved in the project. In particular, the optical network is composed of six observatories located at medium and equatorial latitudes. The LEDSAT mission willing to explore new and promising techniques conceived for gathering important information about the status of orbiting objects in Low Earth Orbit (LEO). Through active illumination on the nanosatellite, it will be possible to increase the possibilities for observing it by using the available ground-based telescopes without the need of direct sun illumination. The paper outlines the LEDSAT mission and scientific background, by offering a complete overview about the CubeSat design and the system architecture