Sea Launch
Sea Launch is a unique spacecraft launch service that uses a specially modified floating oil drilling platform, positioned in the equatorial Pacific Ocean, for its launch platform.
Four companies from four countries contribute to Sea Launch, and share in its ownership:
| company | ownership share | contribution |
|---|---|---|
| Boeing (United States) | 40% | system integration, payload enclosures |
| Energia (Russia) | 25% | Block DM-SL upper stage (rocket stage 3) |
| Aker Kvaerner (Norway) | 20% | launch platform (Ocean Odyssey) and command ship (Sea Launch Commander) |
| SDO Yuzhnoe/PO Yuzhmash (Ukraine) | 15% | Zenit-3SL (Zenit rocket stages 1 and 2 with Energia Block DM-SL upper stage) |
Sea Launch rockets are assembled in Long Beach, California and placed in a hangar on the launch platform, which then sails to the equator. The hangar is opened, the rocket is moved to a vertical position, and the crew then gets onto a command ship. Then, with the launch platform unmanned, the rocket is fueled and finally launched.
There are several advantages of an ocean-based, equatorial launch platform over a conventional land-based one:
- The rotational speed of the Earth is highest at the equator, which provides an extra launch "boost";
- The amount of orbital correction required to achieve a geostationary inclination is reduced; and
- An ocean launch reduces risks related to launching over populated areas.
In addition, the Sea Launch consortium also claims that launch-related operating costs are lower than a land-based equivalent would be, due in part to reduced staff requirements. [1]
The first demonstration satellite was launched in March 1999, and the first commercial satellite in October 1999. In total, Sea Launch has launched 16 rockets, with 15 successes. The one failure, of a Hughes-built communications satellite owned by ICO Global Communications, occurred on the second commercial launch in March 2000 and was blamed on a software error that failed to close a valve in the second stage of the rocket.
All commercial payloads to date have been communications satellites intended for geostationary orbit, with such customers as Echostar, DirecTV, XM Radio, and PanAmSat.
Sea Launch has a reciprocal agreement with Arianespace, providing assurance in case either company’s system is not able to launch a payload, whether for reasons of reliability, capacity, backlog, or otherwise. This was used for the first time in 2004, when Arianespace’s Ariane 5 had to reschedule a group of launches for reliability reasons.
Launches
| Date | Payload | Mass | Comments |
|---|---|---|---|
| March 27 1999 | DemoSat | 4.5 t | success |
| October 9 1999 | DIRECTV 1-R | 3.5 t | success |
| March 12 2000 | ICO F-1 | 2.7 t | failure |
| July 28 2000 | PAS-9 | 3.7 t | success |
| October 20 2000 | Thuraya-1 | 5.1 t | success |
| March 18 2001 | XM-2 ROCK | 4.7 t | success |
| May 8 2001 | XM-1 ROLL | 4.7 t | success |
| June 15 2002 | Galaxy IIIC | 4.9 t | success |
| June 10 2003 | Thuraya-2 | 5.2 t | success |
| August 7 2003 | EchoStar IX/Telstar 13 | 4.7 t | success |
| September 30 2003 | Galaxy XIII/Horizons-1 | 4.1 t | success |
| January 10 2004 | Telstar 14/Estrela do Sul 1 | 4.7 t | success |
| May 4 2004 | DIRECTV-7S | 5.5 t | success |
| June 28 2004 | Telstar-18 | 4.8 t | partial failure |
| March 1 2005 | XM-3 | 4.7 t | success |
| April 26 2005 | SPACEWAY-1 | 6 t | success |
| June 23 2005 | Intelsat IA-8 | 5.5 t | success |
See also
- Expendable launch system
- San Marco platform, part of a similar program in the 1970s and 1980s