Zenit-2

History

The Zenit-2 was designed to fill a gap in the Soviet launch vehicle lineup, carrying between 13 and 15 tons to low Earth orbit. That put it above the Soyuz, which could lift about 7 tons, and below the heavy Proton, which could manage 20 tons. Planners intended to certify it for crewed missions, and a dedicated launch pad was built at the Baikonur Cosmodrome for that purpose. The rocket was meant to launch the Zarya spacecraft, a partially reusable crewed vehicle developed in the late 1980s, but that program was cancelled. Around the same time, Vladimir Chelomey’s design bureau proposed the Uragan spaceplane, which would have carried 15 tons and used the Zenit-2 as its booster, but that project never left the drawing board. A modified version called the Zenit-2S serves as the first two stages of the Sea Launch Zenit-3SL rocket. Launches of the Zenit-2 take place at Baikonur’s Site 45/1. A second pad, Site 45/2, was built but saw only two launches before an explosion destroyed it. A third pad at Plesetsk Cosmodrome, Site 35, was never finished; work stopped after the Soviet Union collapsed. The Zenit-2 flew for the last time in 2004, replaced by the Zenit-2M, which incorporated improvements from the Zenit-3SL program. The Zenit-2 had a low flight rate because the Russian government generally avoided putting national-security payloads on Ukrainian-built rockets. The Zenit-2M itself flew only twice, in 2007 and 2011. In the late 1990s, the Zenit-2 was offered for commercial launches, but only one such mission took place: a cluster of Globalstar satellites that failed when a computer error cut off the second stage early. The Zenit-2’s second stage, known to Western governments as the SL-16, together with the second stages of the Vostok and Kosmos rockets, accounts for about 20 percent of all launch debris mass in low Earth orbit. One analysis found that of the 50 most concerning debris objects in that orbit, the top 20 were all SL-16 upper stages.