Free-Space Laser Communication Activities in Europe: SILEX and beyond

On November 20th, 2001 the European Space Agency (ESA) performed the world-first Semiconductor-laser Inter-satellite Link EXperiment (SILEX) between its data-relay satellite ARTEMIS and the Earth observation satellite SPOT-4. Hundreds of laser communication links have been established since (on average one per day), which prove that the extremely demanding pointing, acquisition and tracking requirements associated with optical wavelength can be reliably mastered and that laser communication technologies are a viable alternative to radio communications in space. On December 9th, 2005 the Japanese OICETS satellite became the second user of ARTEMIS´ optical data-relay services and in the second half of 2006 the French LOLA experiment will become the third demonstrating laser communication from an airplane. On October 31st, 2006 a German second generation laser communication terminal is scheduled for launch onboard the TerraSAR satellite with its partner terminal due for launch onboard the NFIRE satellite in 2007. This new type of terminal will also be used to demonstrate high-speed data-relay services via ESA´s next generation telecommunication satellite AlphaSat in 2010