Sea Launch is a commerical space launch partnership between Boeing, RSC Engergia, SDO Yuzhnoye/PO Yuzhmash, and the Anglo-Norwegian Kvaerner Group.

Sea Launch uses two ships, a launch platform and a command ship, that sail to the equator; the Kvaerner Group contributes the ships.

By launching from the ocean, Sea Launch is able to schedule their own launches and operate with a reduced infrastructure. The equatorial launch site also maximizes the payload capacity and orbit-placement flexibility.

The launch vehicle is a hybrid, its lower states coming from the Zenit-3SL (SDO Yuzhnoye/PO Yuzhmash). The upper state is a Block DM, from RSC-Engergia.

Sea Launch first became operational from its home port of Long Beach, California, in 1999.