The most important space organizations have banded together in the Inter-Agency Space Debris Coordination Committee (IADC) to observe space debris and its effects. Measurement data from all stations around the world is collected and evaluated by the IADC. The high power tracking and imaging radar TIRA, which has a reflector diameter of 34 meters, is the only instrument in Europe capable of recording and measuring the re-entry phase of the satellite. The tracking radar is capable of detecting and observing ROSAT independent of daylight and weather conditions. In addition, the researchers can use the radar images and videos to see if parts of the satellite have broken off and recognize changes in the tumbling motion of the satellite. Changes in the size, weight or proper motion can affect the orbit of the satellite. The orbital data calculated by the team at FHR and the information gathered from radar images flows into the global data warehouse and serves as a basis for the re-entry forecast.

The German Aerospace Center [Das Deutsche Zentrum für Luft- und Raumfahrt (DLR)] was responsible for the ROSAT mission and is now also monitoring the re-entry. According to the latest estimates, re-entry should take place on the coming weekend, 22/23 October – between 5 a.m. Saturday morning and 11 p.m. Sunday evening.

Dr. Klemens Letsch from FHR explains: "The exact crash location is still unknown. Although there are measurement and observation stations all over the world, more data and know-how on the causes and effects of such a re-entry is still required. Many factors play a role here. Firstly, it orbits the Earth in just 90 minutes and will therefore orbit the Earth another 28 times in the defined period. The re-entry is also affected by the proper motion and size of the satellite as well as by solar activity. The orbit of the debris can only be determined 6 – 8 hours prior to the crash and a number of locations can then be ruled out with a high degree of certainty. The re-entry area, however, can only be precisely determined approx. 60 – 90 minutes in advance. The data we are now obtaining can be used to further improve the forecasting techniques".

Fraunhofer FHR has conducted research into space observation with radar for many decades already. The expertise of our scientists and the high power radar system are in demand worldwide. Fraunhofer FHR was actively involved in the monitoring of the re-entry of the Russian space station MIR in 2001 and the crash of the American satellite UARS in the Pacific on 23 September 2011.