Launching Satellites From the Ocean

The two giant ships, a NASA-like mission control and a launch pad floating on the ocean, form part of an audacious, outrageously expensive, multi-national venture for blasting commercial satellites into space. 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. Operated by the Russians, this commercial spacecraft launch service uses a mobile sea platform for equatorial launches of payloads on specialized Zenit 3SL rockets. Since the first rocket flight on March 1999, it has assembled and launched thirty-one rockets, with three failures and one partial failure.

But why launch from the sea when there are land based launching sites, you may ask? Launching from a vessel allows engineers to move the launch pad closer to the equator of the earth, and take advantage of the greater rotational speed of the Earth to provide an extra boost to the launch. Earth’s rotation speed at the equator is 1,674 km/hr. In contrast, the rotational speed of the Earth at Kennedy Space Center, for example, which is located at 28.59° North latitude, is 1,470.23 km per hour. Rockets launched from near the equator thus gains an additional 200 km/hr boost, compared to those launched from Kennedy Space Center.

Launching satellites into geosynchronous orbit (allowing the satellite to keep pace with the earth's rotation) from the equator has another advantage: there is no need to change plane, as the satellites are launched from the same plane as that of the geostationary orbit. This provides another boost as no energy is spent orienting the vehicle. This allows 17.5%-25% more mass to be launched to geostationary orbit than the same rocket launched from Kennedy Space Center.

The ship and launch platform operate from the home port in Long Beach, California., where the customer satellite is encapsulated in a Boeing-built fairing/adapter. The satellite is moved to the ship, where it is mated to the three-stage rocket, which then is moved to the launch platform for transportation to the launch site, where it is moved into upright position. The rocket is automatically fueled and launched as engineers and customers control events from the nearby command ship.