The Zenit-2 was the first Zenit to be designed for use as an orbital carrier rocket. It consists of two stages. The first uses an
RD-171 engine, and an
RD-120 engine powers the second stage. It first flew on 13 April 1985, two years before the Energia, due to delays relating to the Energia's development. Zenit-2 would be certified for crewed launches and placed in specially built
launch pad at
Baykonur spaceport, carrying the new crewed partially reusable
Zarya spacecraft that developed in end of the 1980s but was canceled. Also in the 1980s
Vladimir Chelomey's firm proposed never realised 15-ton
Uragan spaceplane launched by Zenit-2. Two launch facilities were constructed for the Zenit at Baikonur, but the second was only ever used twice. On October 4, 1990, an attempted launch of a Tselina-2 naval reconnaissance satellite ended in disaster as the booster suffered a first stage engine failure seconds into launch and fell back onto the pad, which was severely damaged in the ensuing explosion. The failure was traced to a leak in a LOX line that caused a fire in the thrust section of the booster. Estimated repair costs were about 45 million rubles, but the collapse of the Soviet Union meant that there were no funds available, so the pad was abandoned. Following two failures in 1991–92 both caused by the second stage, the Zenit was on the verge of being cancelled entirely, but a successful flight in November 1992 saved the program. The rate of Zenit launches slowed to a trickle during the 1990s due to the severely cash-strapped Russian Federation, and also because of Russia's reluctance to fly military payloads on a booster manufactured in now-independent Ukraine. On May 20, 1997, a launch of a Tselina-2 satellite failed when the first stage shut down 48 seconds into launch. The booster crashed downrange. During the 2000s, Zenit would find a new lease on life as the basis of the international Sea Launch project whereby commercial flights would be undertaken from an offshore launch platform. The basic Zenit booster received several upgrades to the propulsion and avionics systems for Sea Launch as well as a third stage, and the first test with a dummy payload was carried out on March 27, 1999. In October, a Direct TV 1-R satellite was orbited successfully. An ICO F-1 comsat was lost in March 2000 due to a second stage guidance malfunction. There followed eight consecutive successful launches until Apstar 5 in 2004 suffered a premature third stage shutdown that left it in an incorrect orbit, but the satellite's onboard engines corrected it. After nine successful launches, the Zenit produced a repeat performance of the 1990 disaster when on January 30, 2007, the first stage lost thrust and exploded. The flame deflector on the Sea Launch platform broke off and sank into the water. Loose debris had been sucked into a turbopump, resulting in engine failure. By the late 2000s, the Zenit program at Baikonour was reviving and would see considerable success. On February 1, 2013, an Intelsat satellite launched from the Sea Launch Odyssey platform in the equatorial Pacific. The nighttime launch performed nominally for about 20 seconds when the first stage abruptly lost thrust. Approximately 40 seconds after liftoff, all telemetry data ceased. Subsequent investigation showed that the Zenit had begun deviating from its flight path when the pitch and roll maneuver started. The onboard computer sensed an abnormal situation and sent an automatic shutdown command to the first stage at T+23 seconds, and impact with the ocean occurred about one minute after liftoff. Ultimately, the failure was traced to a defective hydraulic pump that controlled gimbaling of the first stage engines. This resulted in the booster starting an uncontrolled rolling motion which caused the computer system to terminate all thrust. Although anomalous conditions began around T+11 seconds, the Zenit's flight computer was "locked" to prevent engine shutdown until at least 20 seconds after liftoff so the booster would not come down on or near the launch complex. Impact occurred about two miles downrange, but attempts to recover booster debris were unsuccessful. In February 2015, following a year of strained relations as a result of a
Russian military intervention into Ukraine, Russia announced that it would discontinue its "joint program with Ukraine to launch
Dnepr rockets and [was] no longer interested in buying Ukrainian Zenit boosters, deepening problems for [Ukraine's] space program and its struggling
Yuzhmash factory." Strained relations between Ukraine and Russia after 2014 have led to
Russian Federal Space Agency intending to purchase no more of the Zenit first-stage boosters made by Yuzhmash (powered by Russian engines). However 2 Zenit rockets that have been delivered to Russia for
Russian Federal Space Agency missions will still be used; another Zenit rocket for launching a Ukrainian satellite has been completed but without engines due to lack of funding for payments. The world market for Zenit launch vehicles has shriveled since Sea Launch suspended operations, and the future of Zenit is uncertain. Despite the ongoing conflict between the two governments, a Zenit rocket was launched in December 2017, after a two-year hiatus, to deliver
AngoSat 1. ==Production==