Zenit 3SL

The Zenit rocket (Ukrainian: Зеніт, Russian: Зени́т; meaning Zenith) is a space launch vehicle designed by the Yuzhnoye Design Bureau of Ukraine. Zenit was built in the 1980s for two purposes: as a liquid rocket booster for the Energia rocket and, equipped with a second stage, as a stand-alone rocket. Moreover Zenit was planned to take over manned spaceship launches from Soyuz, but these plans were abandoned after the fall of the Soviet Union.

Zenit 3SL on the launch pad

Zenits are launched from Russia's Baikonur Cosmodrome in Kazakhstan, and by the Sea Launch consortium's floating launch platform in the Pacific Ocean. The engines of the Zenit's first and second stages as well as the upper stage of the Zenit-3SL rocket are supplied by Russia. Since the Zenit is not built in Russia, it is planned to be replaced in that service by the new and yet unflown Angara rocket, although Russia does still use the Zenit. There are plans to use an improved Zenit-3SLB rocket for commercial launches from Baikonur Cosmodrome beginning in April 2008. This service is marketed as "Land Launch."

Zenit-3SL has launched 29 times with 26 successes, 2 failures, and 1 partial success as of January 2009. The first failure, of a Hughes-built communications satellite owned by ICO Global Communications, occurred on the second commercial launch on March 12, 2000 and was blamed on a software error that failed to close a valve in the second stage of the rocket. The second failure occurred on January 30, 2007 when the rocket exploded on the Ocean Odyssey launch platform, seconds after engine ignition. The NSS-8 communication satellite onboard was destroyed.

In a study of 16 launchers, the Zenit 2 was, as of March 18, 2001, the lowest cost vehicle for achieving LEO in terms of payload weight per launch ($1167-1667 per pound), and one of the lowest in terms of total costs per launch ($35-$50 million).

• First stage engine: RD-171