Laser measurements to space debris from Graz SLR station

In order to test laser ranging possibilities to space debris objects, the Satellite Laser Ranging (SLR) Station Graz installed a frequency doubled Nd:YAG pulse laser with a 1 kHz repetition rate, a pulse width of 10 ns, and a pulse energy of 25 mJ at 532 nm (on loan from German Aerospace Center Stuttgart – DLR). We developed and built low-noise single-photon detection units to enable laser ranging to targets with inaccurate orbit predictions, and adapted our standard SLR software to include a few hundred space debris targets. With this configuration, we successfully tracked – within 13 early-evening sessions of each about 1.5 h – 85 passes of 43 different space debris targets, in distances between 600 km and up to more than 2500 km, with radar cross sections from >15 m2 down to <0.3 m2, and measured their distances with an average precision of about 0.7 m RMS.

► Using laser ranging, we measured distances to space debris objects. ► We used a 1 kHz/25 mJ/10 ns/532 nm laser, and we built. ► New single-photon detector units, with 500 μm diodes, and low dark noise. ► More than 85 passes of 43 different debris targets were measured. ► Distances to targets were between 600 km and more than 2500 km.