The Ariane 5 launcher will conduct its first operational and commercial flight from Kourou, French Guiana, on 10 December. It will carry the $1 billion X-Ray Multi Mirror (XMM) telescope - Europe's largest-ever science satellite.

The first full commercial Arianespace-operated mission - Ariane 504 - will place the 10m (30ft)-long XMM telescope into a 7,000 x 114,000km orbit in 48h.

The Ariane 5 needs to perform perfectly to bolster its commercial reputation following three test and demonstration missions, the first of which exploded with the loss of four European Space Agency Cluster science satellites in June 1996.

A second flight in October 1997 failed to place the test payloads into a perfect geostationary transfer orbit (GTO). However, last October, a third placed a dummy communications satellite into GTO and launched a recoverable atmospheric re-entry capsule.

Despite its earlier failures, Ariane 5 has won firm commercial contracts for 14 payloads in Arianespace's 42 contract list. Most of the other craft are manifested on Ariane 4s, which have clocked up 49 consecutive successful missions.

Source: Flight International