Eutelsat W3B, launched in the early hours of Friday morning, is considered lost following an otherwise smooth start to the Ariane 5 mission it shared with the BSAT-3b satellite. According to Eutelsat, an anomaly occurred with the satellite’s propulsion subsystem.

In a statement, Michel de Rosen, Eutelsat CEO, said: “The loss of the W3B is a disappointment for Eutelsat and our customers. We share it with our partners, particularly Thales Alenia Space and the insurance community. We will now focus our attention on the delivery of the W3C satellite for entry into service at 16 degrees East by mid-next year and the implementation of a new satellite programme to compensate for this loss.”

The company said it is insured against the financial implications of the loss of satellite. Just 24 hours before the launch, Eutelsat closed a new insurance agreement for the next 5 launches.

“We know the nature of the anomaly, but we don’t know what caused the anomaly,” said De Rosen during a press briefing in Kourou this morning. “What we know is that we have a significant leak in one of the two tanks. The leak is such that we cannot bring the satelite to its position to fulfill its mission. We are still receiving data from satellite, so we will now try to analyse the data.”

Eutelsat said the current three satellites that W3B was set to replace have enough lifetime left to continue the current services at 16 degrees East. The Eutelsat W3C satellite will launch in July 2011 and be placed at this location. De Rosen said it is working with the manufacturer to see if the buyilding proceess can be speeded up, without giving up strict quality control.

Lifting off on time at 18.51 local time from the Spaceport’s ELA-3 launch zone in French Guiana, the Ariane 5 deployed the two craft during a flight lasting just under 38 minutes.

“With this evening’s success, we already have launched eight large telecommunications satellites since the beginning of 2010, which is more than all of our competitors combined,” said Jean-Yves Le Gall, Arianespace chairman & CEO.

The 5,370-kg W3B satellite for Eutelsat was deployed on the Ariane 5 flight 28 minutes into the mission.