Origin of the Zenit rocket
The Zenit rocket became the latest and the most advanced launch vehicle developed in the former Soviet Union in the 20th Century.
The development of the 11K77 launch vehicle, known today as Zenit-2, started at the beginning of the 1970s in the apparent attempt to create a "standartized" family of light, medium and heavy lauchers.
According to KB Yuzhnoe sources, the design bureau considered a family of three launchers in its bid for the government assignment to create a "standard" family of launchers:
All three vehicles were designed to share propulsion and control systems, booster and upper stages, processing and launch facilities. For the 11K37 vehicle KBTM bureau's Department 8 (PKO-8) studied a launch complex with the vertical assembly of the vehicle on the launch pad. It would be the first precedent for this type of launch processing in the USSR. The design experience was later applied toward the Angara project. (103)
A three-booster 11K37 vehicle would use RD-170 engine on each of its pair of strap-on boosters. The core stage would ignite in stratosphere, everal seconds before separation of two strap-ons.
Out of three proposals, the Soviet space forces, VKS, was primarily interested in the 11K77 version, to which KB Yuzhnoe gave a priority in development. The preliminary design of the 11K77 vehicle was completed in April 1974. However in 1975, the original configuration of the rocket, featuring multi-modular architecture, was abandoned in favor of a single-module booster.
On March 16, 1976, the Soviet government officially approved the development of the 11K77 Zenit project. In agreement with NPO Energia, the Zenit's first stage was chosen as a base for the strap-on boosters of the Energia super heavy-lift launcher. The original plans called for the first test launch of the Zenit rocket in 1982.
Sometime in the second half of the 1970s, the Ministry of the General Machine Building, overseeing space industry in the USSR, also proposed the Zenit as a launch vehicle for a super-secret Tselina-2 electronic intelligence satellites, also in the development at the time.
However, the developers of the super-powerful engine of the first stage for Zenit run into considerable trouble. Between 1981 and 1983, the problems plagued the test firings of the RD-171 engine. One of the solutions proposed at the time called for the use of one-chamber engines from the first stage of the N1 rocket.
On top of the difficulties with the engine development, the financial problems in the industry in the mid-1980s further slowed down the program.
The testing of the Zenit launcher was officially completed in December 1987.
In December 1990, with completion of the second (left) launch pad in Baikonur, the complex of the Zenit-2 rocket and Tselina-2 spacecraft was officially accepted into armaments.
In the 1990s, the RKK Energia started the negotiations with the potential partners on forming a joint venture with a purpose of launching commercial payloads from a floating platform. The project became known as Sea Launch.
In June 2001, Sea Launch officials announced that they offered NASA to use the Zenit rocket and its ocean-based platform to transport cargo to the ISS.
After 2000, KB Yuzhnoe also briefly considered upgrading the Zenit rocket with a second side booster, which could be used on the Sea Launch platform. It could deliver around 25 tons of payload into the low Earth's orbit. A three-booster version of the rocket was also evaluated for delivering between 30 and 38 tons. Finally, a four-booster variant would have an estimated payload of 54 tons.
In 2014, the Russian annexation of Crimea and the resulting conflict in the East of Ukraine dealt a blow to all Russian-Ukrainian economic ties, including space cooperation. The production of the Zenit rocket was virtually frozen leaving the future of the launch vehicle in limbo.
Overview of the Zenit launch vehicle family:
Specifications of the Zenit-2 rocket (two booster stages):
Zenit development cooperation:
Next chapter: Zenit's first stage
This page is maintained by Anatoly Zak
Last update: August 13, 2018
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A fully-assembled Zenit-2 booster is used for personnel training in the assembly building in Baikonur. Copyright © 2000 Anatoly Zak
The 11K55 project -- the "light" version of the Zenit launcher. Credit: KB Yuzhnoe
The 11K37 project -- the "heavy" version of the Zenit. Credit: KB Yuzhnoe
A cutaway view of the three-stage Zenit-3 launch vehicle, equipped with Block-D upper stage. Zenit-3 would be able to deliver one (1) ton of payload to the geostationary orbit after its launch from Baikonur. Zenit-3 has never flown from Baikonur but, later became a base for the Sea Launch project. Copyright © 2001 RussianSpaceWeb.com
The Svityaz project -- the air-launched version of the Zenit rocket, carried on top of a Mriya transport plane. Credit: KB Yuzhnoe
After year 2000, KB Yuzhnoe in Dnepropetrovsk, Ukraine, considered upgrading the Zenit rocket for the Sea Launch venture with a second asymmetrical booster, as well as building a three-booster configuration. Copyright © 2013 Anatoly Zak
The RD-170 engine powered the first stage of the Energia rocket. Copyright © 2005 Anatoly Zak
The RD-120 (11D123) engine powers the second stage of the Zenit launcher. Copyright © 2001 Anatoly Zak
An adapter built by RKK Energia's manufacturing arm for the Zenit rocket used in the Land Launch venture. Copyright © 2011 Anatoly Zak