Alenia Spazio says its Artemis communications technology satellite operated by the European Space Agency (ESA) has almost reached geostationary orbit (GEO) after its botched launch aboard an Ariane 5 booster a year ago.


Artemis is 3,000km short and will reach GEO in early 2003 after a unique trouble-shooting procedure devised by engineers. The satellite will provide the European Global Navigation Overlay System (EGNOS), a precursor to the European Galileo navigation satellite fleet.

The satellite also carries a revolutionary Silex optical communications relay system to support the French Spot Image commercial remote sensing satellites, and will operate an L-band transponder for Eutelsat and relay Ka-band data for ESA's Envisat polar platform.


The ESA-funded Artemis was left stranded in a lower transfer orbit than planned due to an Ariane upper stage malfunction. Instead of an elliptical geostationary transfer orbit with an apogee of 35,853km, which was to have been circularised to GEO by an engine firing, Artemis was stranded at 17,487km apogee.

Alenia Spazio, ESA and contractor engineers devised an innovative solution, using the spacecraft's pioneering ion propulsion system, slowly nudging the satellite into a higher orbit. With a thrust of just 15 milli-Newton, the ion engine moved the satellite 15km a day. More than 20% of the craft's control software had to be modified for the new procedure.

During the long orbit transfer operations, Artemis successfully demonstrated the on-board communications payloads, including establishing an optical link with the Spot 4 satellite

Source: Flight Daily News