DLRs Johannes Kepler Observatory for LEO RSO Analysis and Technology Development

Abstract

DLR’s Johannes Kepler Observatory (JKO) was inaugurated in 2022 and features a 1.75 m telescope (Ritchey-Chrétien design) at a site close to DLR’s Institute of Technical Physics in the Northern Black Forest. Main objectives are the development of technology in the near-infrared (NIR) spectral region for LEO RSO analysis. Three main research topics are covered: passive (camera) observations, active laser ranging, and spectral analysis. LEO RSO camera observations with the 1.75 m telescope are performed using a sCMOS camera with high frame rate and quantum efficiency. The high frame rate enables observations with a minimum of distortions due to atmospheric turbulence. Post-processing of image data and light curve data are performed to obtain rotational state and attitude information. A piggy-back mounted astrograph enables wide FOV (field of view) observations and RSO catalogue comparison. RSO laser ranging at JKO is performed with laser systems in the NIR spectral region with pulse lengths of nanoseconds (ns) and picoseconds (ps). Eye-safe NIR laser systems are being deployed to enable RSO ranging in a crowded airspace. JKO ranging measurements can be supported by bistatic measurements using a transportable laser ranging station (STAR-C, Christoph Huber et al., this conference). For RSO material analysis, reflected sunlight at the RSO is collected with the 1.75 m telescope and coupled in an optical fiber for analysis with a NIR grating spectrometer. Overall goal is to obtain an extended RSO catalogue including spectral information. For VLEO RSO it is planned to study material aging effects. This contribution introduces the JKO and presents current status of camera and laser ranging observations of LEO RSO. Special focus will be presentation of a novel eye-safe laser ranging system to LEO RSO and analysis of signal dynamic range and detection limits.