Universal Rocket

The UR-100 and its variants (e.g. UR-100N) were the standard small ICBM of the Soviet Union during the Cold War. Only the UR-100N (NATO reporting designation: SS-19 Stiletto) remains in active duty , with 20–30 missiles operational.[1] The Strela and Rokot carrier rockets are based on the UR-100N. A number of UR-100Ns have been earmarked for use as launch vehicles for the Avangard maneuverable reentry vehicle.[2]

The UR-200 was intended to be a larger ICBM that could also be used as a carrier rocket. Nine test flights were made between 4 November 1963, and 20 October 1964, before the program was cancelled in favor of Mikhail Yangel's R-36 missile and Tsyklon carrier rocket derivative.

The UR-500 was designed to be a very large ICBM, with the throw-weight necessary to deliver the 50-100 megaton Tsar Bomba like warhead.[3] Under pressure from Khrushchev, the UR-500 was reworked as a space launcher, and eventually renamed the Proton, the latest version of which is still in service as of 2020.

UR-700

The UR-700 was Vladimir Chelomei's heavy-lift entry for the Soviet moonshot. It was meant to carry cosmonauts to the Moon on a direct ascent mission in the LK-1 lunar craft. Sergei Korolev's N1 booster and Soyuz 7K-LOK / LK Lander were chosen instead for the mission, and it never left the drawing board. It would have had a payload capacity to low earth orbit of 151 metric tons.[4]

Superficially, the UR-700 was of the well-known design of Soviet launchers with a central core stack and lateral strap-on boosters. But one distinguishing feature was that the engines of the first stage were cross-fed with fuel and oxidizer from the tanks of the strap-on boosters during the initial flight phase. This meant that when the boosters were spent and jettisoned, the central stack still flew with full tanks, thus reducing dead weight and increasing a possible payload.[5]

A nuclear variant known as the UR-700m was also designed that would have a payload capacity of 750 t (1,650,000 lb) to LEO and be used to assemble the 1400 t (3,000,000 lb) MK-700 spacecraft in earth orbit in 2 launches.[6]

The UR-900 was the ultimate Universal Rocket application, a super heavy-lift launch vehicle for crewed expeditions to other planets, especially Mars. Proposed in 1969, it would have had 15 RD-270 modules in the first and second stages, and the third and fourth stages were based on those of the UR-500. The UR-900 would have stood 295 feet tall, had a liftoff thrust of 21,132,000 lbf, and be able to place 240 tons into low earth orbit. Like the UR-700, it remained a paper project only.[7]

• List of space launch system designs

• Mark Wade. "Universal Rockets". friends-partners.org.
• Mark Wade. "UR-100". Astronautix.com.
• Mark Wade. "UR-200". Astronautix.com.
• Mark Wade. "UR-700". Astronautix.com.
• Mark Wade. "UR-700M". Astronautix.com.
• Mark Wade. "UR-900". Astronautix.com.