Launch Date Uncertain for Third Inmarsat I4 Satellite

 - May 29, 2008, 11:50 AM

The failure of a Russian Proton rocket in March has thrown the schedule for the launch of Inmarsat’s third and final I4 communications satellite into question, according to Inmarsat officials speaking today at a satellite user conference in San Diego. The third satellite supporting SwiftBroadband aero data and voice services will be positioned over the Pacific Ocean region, completing the I4 coverage network. Inmarsat is awaiting the results of a launch failure board review, convened after the premature shutdown of the Russian rocket, caused by a ruptured exhaust gas duct. This was the third failure of this type of rocket since 2006, although a government board in Moscow has said there is no particular flaw with the rocket design. The third I4 satellite is to be launched from Kazakhstan sometime after the review board decision, expected next month, officials said. “In this century there have actually been five Proton failures, and the longest that it has taken to return to flight has been 150 days,” said Eugene Jilg, vice president of product evolution for Inmarsat. “I think we’ll be highly disappointed if we set a record for the longest return to flight” following a Proton rocket failure.