Sea Launch is a spacecraft launch service that uses a mobile sea platform for equatorial launches of commercial payloads on specialized Zenit 3SL rockets. It has assembled and launched thirty-one rockets, with two failures and one partial failure.
The sea-based launch system means the rockets can be fired from the optimum position on Earth's surface, considerably increasing payload capacity and reducing launch costs compared to land-based systems.
Sea Launch was established in 1995 as a consortium of four companies from Norway,Russia, Ukraine and the United States, managed by Boeing with participation from the other shareholders. The first rocket was launched in March 1999.
All commercial payloads have been communications satellites intended for geostationary transfer orbit with such customers as EchoStar, DirecTV, XM Satellite Radio, and PanAmSat.
The launcher and its payload are assembled on a purpose-built ship Sea Launch Commander in Long Beach, California, USA. It is then positioned on top of the self-propelled platformOcean Odyssey and moved to the equatorial Pacific Ocean for launch, with the Sea Launch Commander serving as command center.