On February 10 at approximately 1656 GMT, the Iridium 33 and Cosmos 2251 communications satellites collided over northern Siberia. A 24-hour EISCAT space debris measurement using the Tromso UHF radar and a dedicated "piggy-pack" receiver was conducted on 14th-15th February, 2009 by a team of Finnish EISCAT scientists with the help of EISCAT staff. Clear increase in the space debris detections is seen at the orbit altitude around 800km.

The space debris experiment was optimized for simultaneous incoherent scatter observations, in order to demonstrate the feasibility of such experiments. The main idea is to use non-uniform IPPs to be able to receive echoes from all ranges. Typical EISCAT measurements leave a large part of the ranges blank because the each transmission block echoes from the same ranges.

The EISCAT results were presented on Monday this week at the ESA-hosted 5th European Conference on Space Debris , which is organised at ESA's Space Operations Centre (ESOC) in Darmstadt, Germany 30.3.-2.4.2009.

Another important EISCAT result was shown Tuesday, based on the ESR space debris measurements during the International Polar Year operations on Svalbard. The ESR measurements were the longest continuous data series in the history of space debris observations. While typical space debris observations are based on occasional 24h continuous experiments, the ESR operations provided a 5000 hours database. ESR was also used for detecting the effect of the Iridium-Cosmos collision by an experiment on 19.-20. February, 2009.

CREDITS: 1) "Measuring Space Debris with Phase Coded Aperiodic Transmission Sequences", presented at the 5th European Conference on Space Debris by Vierinen, J.; Markkanen, J.; Lehtinen, M.S. (Sodankylä Geophysical Observatory , Finland ; EISCAT Scientific Association). 2) "EISCAT Space Debris during the IPY - a 5000 Hour Campaign", presented at the 5th European Conference on Space Debris by Markkanen, J.; Jehn, R.; Krag, H.; EISCAT Scientific Association; ESA/ESOC (Germany). 3) ISR analysis by Ilkka Virtanen (University of Oulu, Finland).