UR-100N / SS-19 STILLETO
Russia test-fired an old Soviet intercontinental ballistic missile on 22 October 2008 as part of efforts to check on the weapon's reliability and extend its service. A spokesman for Russia's strategic missile forces, Colonel Alexander Vovk, said the military launched the RS-18 missile from the Baikonur space center in Kazakhstan. He said the launch confirmed its reliability. As a result of the successful launch at 13.10 Moscow time (09:10 GMT), the Stiletto ICBMs, which had so far been operational for 29 years, will remain on combat duty beyond 2010 [reports that the October 2008 test supported a decision to extend use of the missile until at least the year 2031 are based on a misunderstanding]. The launch confirmed the service life of the missile, which had been set to 31 years earlier in 2008 after a successful launch in October 2007. Moscow started using the RS-18 missile, which NATO calls the SS-19 Stiletto, in the 1970s. Russia's strategic forces have conducted regular test launches of missiles to check their performance. The military has repeatedly extended the lifetime of Soviet-built weapons as the government lacks the funds to replace them quickly with new weapons.
Once regarded as the "backbone" of the Soviet ICBM force, the fourth generation UR-100N / SS-19 intercontinental ballistic missile was a tandem two-stage, storable liquid-propellant ICBM. The missile was approximately 80 feet long and 8 1/2 feet in diameter. It was a competing design with the SS-17 Spanker, and both were eventually deployed to partially replace the aging SS-11 force as the SS-11 reached its operational life expectancy.
The UR-100N was similar to the UR-100 in some respects, but with an increased diameter and longer propellant tanks its launch weight was more than doubled and the throw-weight was increased over three-fold than that of the UR-100. Like many 4th generation systems, the UR-100N used asymmetrical dimethylhidrazine and nitrogen tetraoxide propellants. The first stage consisted of four autonomous closed-cycle single-chambered rocket motors, while the second stage had a closed-cycle single chambered sustainer and a four chambered open cycle control motor with four rotating nozzles. The guidance and control system of the SS-19 was identical to the SS-18 and permitted remote monitoring of missile status while on alert. Remote monitoring also allowed for automatic pre-launch preparation, remote missile targeting before launch and in-flight control of the missile via a flexible pitch control program. Unlike the UR-100MR, the UR-100N could not use existing silos. As a result new silos were constructed at the same sites as the UR-100U silos. The silos were later completely dismantled and rebuilt to increase the survivability of the new missiles. The UR-100N was launched in the hot mode through the thrust of the first stage sustainer engine.
The SS-19 was deployed in three configurations.
- SS-19 Variant-1 - Through the increase of throw-weight and reduction of the size of the warheads relative to the UR-100 the UR-100N was able to carry six MIRV warheads with a yield of 550 KT according to Russian sources or a a yield of one- to two-megatons suggested by Western estimates. According to Western estimates the booster system was limited to a range of 4900 nm but the total system ( booster plus PBV) was believed to be capable of delivering all six RVs to a maximum range of 5200 nm. Development for the SS-19 Variant 1 was approved on 19 August 1970 and developed by V. N. Chelomey. The flight tests of the UR-100N were conducted at the Baikonur cosmodrome from April 1973 through October 1975. The missile was initially deployed in December 1975, Western believed it achieved an initial operational capability in 1974. The first regiment with UR-100N missiles was put on alert in April 1975 and by the end of 1975 a total of 60 launchers were deployed. The missile utilized an inertial guidance system that was is estimated by some Western sources to have an operational CEP of 0.3 nm in 1975 with a potential CEP of 0.25 nm by 1980. However hasty development of system failed to notice serious problems associated with resonant oscillations that was only discovered following training launches. The resonant oscillations significantly reduced its overall accuracy. Subsequently all deployed missiles were modified to eliminate the problems.
- SS-19 Variant -2 - Otherwise similar to the Variant-1, this variant carries a single warhead with a yield reported by Russian sources of between 2.5 and 5 MT rather than the MIRV system found on variant-1. Between 1976 and 1978 the UR-100N reached its maximum operational inventory of 180 missiles. Sixty of which carried a single warhead. Both of these SS-19 M variants were attributed "hard target kill" capabilities by the West.
- SS-19 Variant -3 -The development of an improved version was authorized on 16 August 1976. The upgrades to the missile involved the development of improved engines and modification of the command system as well as further hardening of SS-19 silos. The protection from a nuclear strike at their silos was considerably improved. The flight-design tests of the improved version that received the designation UR-100NUTTH were conducted between June 1979 and October 1979. Its deployment began in November 1979.
The first regiment with the UR-100NUTTH was put on alert on 06 November 1979. Between 1980 and 1982 UR-100N missiles with a single warhead (SS-19 variant 2) were replaced by the UR-100NUTTH (SS-19 variant 3) which used MIRVed warheads. The replacement of all UR-100N missiles was completed in 1983. In 1984 the UR-100NUTTH reached its maximum operational inventory of 360 missiles. From 1987 on they were gradually replaced by the silo based version of the SS-24.
When START-1 was signed in 1991 the Soviet Union had a total of 300 UR-100NUTTH missiles stationed in both Russia and Ukraine. Following the dissolution of the Soviet Union, Ukraine claimed ownership of all missiles located in its territory. In compliance with the START treaty provisions Ukraine is in charge of the dismantling the launchers for the SS-19 missiles. However, all nuclear warheads that were deployed in Ukraine were dismantled by Russia.
Some 170 launchers remain in Russian territory, of which only ten of the launchers have been deactivated, not dismantled. In December 1995 Strategic Rocket Forces Commander Colonel General Igor Sergeyev announced a policy under which the service life of the SS-19 would be extended from 10 years to 25 years. The missiles will remain on alert at least through 2005, and the missiles that were deployed in the early 1980s will likely serve even beyond this.
Following the ratification of the START-II treaty by the Duma, Russia was obliged to dismantle all ground-based ICBMs with multiple warheads. Under the treaty provisions a total of 105 of the UR-100NUTTH missiles can be retained provided they are downgraded to carry only one warhead rather than the six they were designed to carry. In June 2001 a 26-year-old SS-19 missile was test fired in order to test the reliability of the 20+ year old system. The tests suggested that the system could remain in service beyond 2005. The Stiletto missile was fired from Russia's space base at Baikonur in Kazakhstan. The test came just a week after Russian President Vladimir Putin threatened to deploy multiple nuclear warheads on Russian missiles as a countermeasure to the proposed US missile defense deployment. The Stiletto could be re-equipped to carry up to six warheads.
As of 01 April 2005 Kommersant reported that the Strategic Missile Force of Russia had 496 ICBMs, including 226 silo-launched (86 heavy missiles R-36MUTTH and R-36M2 Voevoda, 10 medium missiles UR-100NUTTH, and 40 light missiles RS-12M2 Topol-M) and 270 mobile ground-launched missiles RS-12M Topol. By 2010, the Force may have no more than 313 ICBMs, including 154 silo-launched (40 R-36M2 Voevoda, 50 UR-100NUTTH, and 64 RS-12M2 Topol M), and 159 mobile ground-launched missiles (144 RS-12M Topol and 15 RS-12M1 Topol M). The number of warheads on the ICBMs will be reduced from 1,770 to 923. [upon close inspection these numbers don't exactly add up and are internally inconsistent, based on standard warhead loading assumptions].
A firing was held in November 2006 to test the performance characteristics of the RS-18 (SS-19 Stiletto) to extend its service life by one year, from 29 to 30 years. Following numerous test launches, RS-18 missiles were considered to be highly reliable. About 97 silo-based Stiletto missiles were deployed as of mid-2008 in the Russian Strategic Missile Forces, with each missile carrying six warheads.
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