General · EdgepediaOctober 15, 20264 min read

Tsiklon-2

Tsiklon-2 (Ukrainian: Циклон-2, "Cyclone-2"), also written Tsyklon-2 and known as Tsyklon-M, was a two-stage Soviet and later Ukrainian orbital launch vehicle, GRAU index 11K69 and designated SL-11 by the United States Department of Defense. Developed by the Yuzhnoye Design Bureau and built by Yuzhmash as a derivative of the R-36 intercontinental ballistic missile, it flew 106 times between 6 August 1969 and 25 June 2006, almost entirely carrying military Kosmos satellites from the Baikonur Cosmodrome.¹^•²^•³

Key fact	Detail
Designations	GRAU index 11K69; US DoD designation SL-11; also called Tsyklon-M¹
Origin	Derived from the R-36 (8K67, SS-9 Mod 1) ICBM with minimal modification; built by Yuzhnoye Design Bureau / Yuzhmash²
Vehicle	Two stages; height 39.7 m; liftoff mass 182 t; liftoff thrust 2,366 kN; LEO capacity 2,820 kg⁴
Launch site	Baikonur Cosmodrome, pads 90/19 and 90/20³^•¹
Final flight	25 June 2006, carrying Kosmos 2421 (US-PM #13)⁵

Vehicle and variants

The Tsyklon-2 was a member of the Tsyklon family of expendable launch systems, which Yuzhnoye developed from its R-16 and R-36 missile designs. Its development was a direct consequence of the R-36 ICBM, from which it was minimally modified to serve as a space launch vehicle.² The first stage used an RD-251 cluster of three RD-250 engines plus an RD-68M steering unit, and the second stage an RD-252 with RD-69M.³

A precursor variant, the Tsiklon-2A, flew first. Its maiden flight on 27 October 1967 opened the Tsyklon family's operational history, and it made 8 flights with a low Earth orbit capacity of 3,000 kg before its last flight on 25 January 1969.² The baseline Tsiklon-2 configuration then took over on 6 August 1969 and remained in service for 37 years.⁶

Missions

Nearly every Tsyklon-2 launch carried a military Kosmos satellite into low Earth orbit. Gunter's Space Page flight list shows the vehicle's workload: US-A naval reconnaissance (radar ocean reconnaissance) satellites, US-P electronic intelligence satellites, and their successor US-PM satellites account for the great majority of flights, alongside IS-A antisatellite test vehicles in the 1970s and 1980s and two Plasma-A satellites in 1987.³ The first flight carried Kosmos 291 (IS-GVM #1).³

From 1993 the vehicle flew almost exclusively US-PM satellites, at a pace of roughly one per year or two: Kosmos 2238 (US-PM #1) in March 1993 through Kosmos 2421 (US-PM #13) on 25 June 2006, all from Baikonur.³^•⁵ The final mission, US-PM 13, concluded a 37-year operational history with a successful launch.⁷

Reliability record

The Tsyklon-2 is noted for an exceptional reliability record. A study of orbital carrier rocket failures describes the Tsyklon family as one of the most reliable, surpassing Ariane, Delta, and Proton, and states that Tsyklon-2, together with the American Atlas II, never experienced a failure of the rocket itself.⁸

The single blemish in the record is disputed. The 25 April 1973 launch of Kosmos (556) (US-A #5) is marked as a failure in some databases, but the failure study states that the launch description attributes it to a failure of the payload's propulsion system, not of the Tsyklon-2 itself, in line with the manufacturer's statement.³^•⁸

Databases disagree on the totals. Next Spaceflight counts 106 missions with a 97.2% success rate (102 successes, 2 failures, 2 partial failures); Orbit Codex counts 113 flights across both configurations with a 97.3% success rate; Padside counts 105 flights with a 98.1% success rate; and Space Stats counts 105 orbital launches.¹^•⁶^•⁹^•⁵ These differences reflect how suborbital flights, the 2A variant, and the 1973 payload failure are classified.

Retirement

Russia stopped purchasing the Yuzhnoye-built rocket in 2006, despite its reliability record, in favor of new-generation all-Russian carrier rockets such as the Angara and Soyuz-2, and the Tsyklon-2 was retired along with the Tsyklon-3.¹⁰^•¹ The last Tsyklon-2 launch took place on 25 June 2006 from Baikonur, carrying Kosmos 2421.⁵

References

Topic: Encyclopedia › Technology and the built world › Transport and spaceflight › Spaceflight › Launch systems and rocketry › Launch vehicles › Launch vehicle families › Soviet and Russian launch vehicle families

Initially written Oct 15, 2026 · Edited: Oct 25, 2026

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