Estimating the Space Debris Density Function using Radar Beam Park Measurements

Estimating the density of space debris as a function of orbital elements and size is crucial for determining the risk of collision of spacecraft. For objects 1 cm or larger in diameter, this information can be obtained using beam park observations made with powerful ground based radars. This study presents a novel technique for estimating the density of space debris as a function of orbital elements and size using the framework of statistical inverse problems, where prior information about e.g., the size and eccentricity distribution can be used to constrain the estimation problem. A key element of this estimation technique is the accurate modeling of the expected number of detections made by a radar. The method is applied to the historical record of EISCAT high power large aperture radar measurements to study the evolution of the space debris environment.