Tim Furniss/LONDON

The Sea Launch offshore launch platform Odyssey has left Long Beach, California, for an equatorial position in the Pacific Ocean 2,253km south of Hawaii, to launch the first Zenit 3SL booster on 26 March.

The historic Sea Launch flight will demonstrate a new commercial launch system operated by a consortium headed by Boeing, which has a 40% stake in the venture with Russia's Energia (25%), Yuzmash of Ukraine (15%) and Norway's Kvaerner (20%).

The launch, carrying a dummy satellite, will be controlled by the Sea Commander vessel anchored close to the platform.

It will be the first satellite launch into geostationary transfer orbit (GTO) to be made from an offshore platform, although nine science satellites were launched into low earth orbit from the Italian San Marco offshore platform between 1966 and 1976.

The Sea Launch Zenit 3SL booster is based on the two-stage Zenit 2 built by Ukraine, with a Russian Proton Block DM restartable fourth stage. It will be capable of placing 5,000kg into GTO from its equatorial location.

This matches the approximate capability of Europe's Ariane 5 and Ariane 44L operated by Arianespace and the Chinese Long March 3B launcher.

The Sea Launch was to have launched the Galaxy XI satellite, but after the failure of a Zenit 2 operated by Ukraine and Russia from Baikonur last September, with the loss of 12 Globalstar satellites, the Galaxy was transferred to an Ariane on the grounds that maiden flights pose an unacceptable risk. Sea Launch then felt it prudent to fly the first Zenit 3SL with a dummy satellite.

The company also lost two of three ICO mobile satellite launches from its manifest after the failure. The remaining ICO satellite is the only definite payload on a commercial manifest which includes reservations by Hughes and Loral.

The maiden Sea Launch mission will be the first of three major launches planned by US companies this year. The second Boeing Delta III is poised on its Cape Canaveral, Florida, launch pad for a flight in April, when it will carry the Orion 3 satellite. This launch follows a catastrophic failure on its first flight, made in August last year.

Lockheed Martin is preparing the first Atlas IIIA for a Canaveral launch. The International Launch Services flight will carry the Telstar 7 satellite, possibly in June.

Source: Flight International