Visibility studies and orbit determination of space debris objects for a combined passive-optical and laser ranging station

Kurzfassung

At the Institute of Technical Physics at the German Aerospace Center (DLR-TP), a proposed concept combines two methods of well established orbital observations: First, optical observations using passive reflection of sunlight, which is in constant use for characterizing space debris in GEO regions. Second, an active satellite range laser ranging, which has been used for decades to measure distances to cooperative LEO and MEO objects at accuracies down to few millimeters. In the new approach, passive optical observations shall first detect space debris objects in LEO regions during twilights and following guide a laser to illuminate the object for a high accurate range measurement. In the scope of this thesis, first a general assessment of the accuracy of initial orbit determination with three different space debris observation techniques (radar, passiveoptical and combined laser ranging and tracking) have been performed, to point out general advantages of the laser ranging methods regarding accuracies. Following, using ESA’s PROOF-2009 (Program for Radar and Optical Observation Forecasting), different studies were performed to assess the general visibility of space debris in LEO regions. These studies have been undertaken both for the, currently under construction, DLR Space Debris Observatory in Stuttgart with the given hardware of this station as well as for more generalized hardware and locations. Results include both the characteristics of detected objects regarding their seizes, as well as variations of their amount over different viewing directions and seasons. Following, a FORTRAN tool has been written to further analyze these detected objects regarding their use for tracking and orbit determination. These final analyses have been performed for different PROOF runs. Results here show that from the total number of detectable objects only a fraction can be used for further determinations.