Spaceborne LiDAR for Debris Detection and Tracking

The NewSpace paradigm is causing a significant growth of space debris, making the risk of catastrophic collisions increasingly high. Satellites in Low Earth Orbit (LEO) already perform two collision avoidance maneuvers on average each year, disrupting the nominal operations and consuming propellant. With a quickly growing space population, this will occur even more often in the future. However, maneuver rates are largely driven by the presence of uncertainties in debris measurements, which are currently performed mainly through ground-based sensors. The data accuracy can be improved by allowing spacecrafts to perform autonomous observations of debris through on-board sensors. Here, an Ultra-Long-Range LiDAR is proposed as a secondary payload for medium-sized or larger (>500 kg) satellites. A preliminary analysis led to the definition of the high-level requirements, such as a range and lateral resolution of 10 m, a Field of View (FoV) ≥ 0.12° × 10° and the ability to scan, within 10 s, a frame of 90 m radius at 500 km. Following those results, a system-level analysis is conducted, to identify the best design choices regarding the method of target illumination, the detection scheme, and the source wavelength (λ). A beam scanning, Frequency Modulated Continuous Wave (FMCW)-based LiDAR architecture, operating in the optical C-band, is identified as the best solution for the proposed application. Then, the required performance for the LiDAR building blocks has been derived.