Feasibility Assessment of a High-Altitude Tethered-Balloon Optical Imaging System for LEO Space Debris Monitoring

To support low Earth orbit (LEO) debris monitoring, this paper investigates a tethered-balloon-based optical observation concept intended to complement ground- and space-based sensors. The system comprises a high-altitude tethered aerostat, an optical payload, a three-axis stabilization subsystem, and a ground control station. Key payload parameters, including field of view, spatial resolution, and atmospheric transmittance, are analyzed, and the configuration is examined in terms of spectral-band selection, aperture, and multi-camera mosaic imaging. A multi-station angular-measurement model and a weighted least-squares estimator are developed for debris localization. Monte Carlo and scenario-based simulations indicate that a wide field of view can increase observation duration and availability, with mean continuous observation arcs exceeding 400 s, thereby improving estimator conditioning and localization performance. A 5 km flight experiment further validates the operability of the SWIR imaging chain through star-field imaging and a representative image-sequence example with a highlighted moving point-source target. The results suggest that tethered balloons can provide a cost-effective and rapidly deployable supplementary observation layer for multi-layer space situational awareness.