The Zenit-3SL was an expendable three-stage launch vehicle used by Sea Launch for commercial satellite launches.

It was a member of the Zenit family of rockets, designed by Yuzhnoye Design Bureau in Ukraine.

The rocket was known for its launches from the Ocean Odyssey platform in the Pacific Ocean. The last flight of a Zenit-3SL was in 2014.

Here's a more detailed overview:

Key Features:

Manufacturer:

Yuzhmash (Zenit), RKK Energia (Block DM), and Boeing (fairing).

Launch Location:

Ocean Odyssey platform at the equator in the Pacific Ocean.

Stages: Three.
Payload Capacity: 6,160 kg to GTO.
First Stage: Powered by an RD-171 engine, burning RP-1/LOX.
Second Stage: Powered by an RD-120 engine.
Upper Stage: Block DM-SL, built by RKK Energia.
Fairing: Provided by Boeing.

History:

First flown on March 28, 1999.
36 launches total, with 3 failures and 1 partial failure.
Last flight was on May 26, 2014.

The Zenit-3SL was a key component of the Sea Launch system, which offered launches from a unique equatorial location.

The system aimed to provide cost-effective access to space for commercial satellites.
The Zenit-3SL was also used in the Zenit-3SLB variant, which launched from Baikonur Cosmodrome.

Significance:

The Zenit-3SL was a significant part of the commercial space launch market, particularly for satellites requiring access to the geostationary orbit.

The Sea Launch concept, with its floating platform, offered a unique advantage for certain types of launches.

The Zenit-3SL's operational history reflects both successes and challenges in the commercial space industry.