Laser Beams Link Satellites

The European Space Agency's Artemis satellite and the Centre National d'Etudes Spatiales' observation satellite, SPOT 4, established a satellite laser data link last November. The link used a 60-W, 850-nm laser diode from SDL Inc., which is now part of JDS Uniphase.

The link system, called Silex, allowed Artemis to relay information from Spot 4 at the rate of 50 Mb/s to the image processing center in Toulouse, France. The European Space Agency's test station in Belgium confirmed the data stream.

The satellites, 30,000 km apart and traveling at a relative speed of 7000 m/s, established the link four times for programmed periods of four to 20 minutes. Operational use of the link is slated to begin in the middle of the year, after Artemis has been moved into a geostationary orbit.