Zenit 3SLB

Zenit 3SLB

The Zenit 3SLB is a three-stage orbital launch vehicle developed as part of the broader Zenit rocket family, originally designed in the Soviet Union and manufactured by Yuzhnoye/Yuzhmash in Ukraine. The "3SLB" designation identifies the land-based variant used by the Land Launch consortium, a commercial venture that operated the vehicle from the Baikonur Cosmodrome in Kazakhstan. It is closely related to the Zenit 3SL, the sea-launched version operated by Sea Launch from a converted ocean platform in the Pacific.

The vehicle's upper stage — a Block DM derivative supplied by Russian manufacturer Energia — provides the high-energy kick needed to deliver payloads into geostationary transfer orbit, making the Zenit 3SLB well suited for the commercial communications satellite market it was designed to serve.

History and Operations

Our flight record covers 42 tracked flights between 1999 and 2014, of which 39 were successful and 3 resulted in failure or partial failure. This represents a strong overall reliability record for a commercially operated medium-to-heavy lift vehicle. The active period spans roughly fifteen years, during which the Zenit 3SL and 3SLB variants together became a notable presence in the commercial launch market alongside competitors such as Ariane 5 and Proton-M.

The vehicle's primary commercial customer was Sea Launch, reflecting the close operational and contractual relationship between the sea-launched and land-based variants of the Zenit family. The majority of missions involved delivering commercial geostationary communications satellites for major satellite operators to geosynchronous transfer orbit.

Notable Missions

Recent missions tracked in our data illustrate the vehicle's focus on high-value commercial payloads. These include flights carrying the Eutelsat 3B, Amos-4, Eutelsat 70B, Intelsat 19, Intelsat 21, and Intelsat 27 satellites — a roster of prominent geostationary spacecraft serving telecommunications customers across Europe, the Middle East, and beyond. The recurring presence of Intelsat and Eutelsat payloads underscores the vehicle's established role in the commercial GEO market during its operational years.

Vehicle Configuration

The Zenit 3SLB's first and second stages are powered by high-performance kerosene/liquid oxygen engines, a propellant combination that gave the Zenit family a reputation for clean combustion and competitive performance relative to older hypergolic-fueled competitors. The Block DM upper stage uses liquid oxygen and kerosene as well, and is capable of multiple restarts, a capability that adds flexibility in reaching precise orbital insertion points. The dimensions noted in our records — a height of 4.6 m and diameter of 0.42 m — reflect component-level measurements rather than the full stack, which stands considerably taller in its launch configuration.

Legacy

The Zenit 3SLB represents an important chapter in post-Soviet commercial spaceflight, demonstrating that Ukrainian and Russian industrial cooperation could compete effectively in the global launch market. Operations wound down after 2014, a period that coincided with significant geopolitical disruption following events in Ukraine, which severely impacted the binational supply chains underpinning the entire Zenit program. Its flight record nonetheless stands as a testament to the vehicle's engineering heritage and commercial relevance during its peak years.