Statistical and radiometric measurements of coherently illuminated, nonaugmented, low-earth-orbit satellites

The US Air Force Phillips Laboratory recently completed the Floodbeam Experiment (FBE), recording the first ever spatially resolved, coherent laser returns from non-augmented (non- retroreflectors), low earth orbit satellites. The experiment broadcast a near-IR, coherent laser at a selected set of low earth orbit satellites using a beam director and visible tracking system located at the Phillips Lab Starfire Optical Range (SOR). Tracking was accomplished during terminator periods when the satellite was illuminated by the sun and the transmitting/receiving site was in darkness. Thirty eight different satel- lites were illuminated during the experiment. The reflected laser return was collected with the 1.5m telescope at the SOR and focused on a low noise IR camera. The Floodbeam experiment gathered radiometric data, data on depolarization effects, and spatially resolved coherent speckle patterns. This paper will discuss the experimental hardware and the field results.