Heavy-lift launch vehicleA heavy-lift launch vehicle (HLV) is an orbital launch vehicle capable of lifting payloads between 20,000 to 50,000 kg (44,000 to 110,000 lb) (by NASA classification) or between 20,000 to 100,000 kilograms (44,000 to 220,000 lb) (by Russian classification) into low Earth orbit (LEO). Heavy-lift launch vehicles often carry payloads into higher-energy orbits, such as geosynchronous transfer orbit (GTO) or heliocentric orbit (HCO).
Soviet space programThe Soviet space program (Russian: Космическая программа СССР, romanized: Kosmicheskaya programma SSSR) was the state space program of the Soviet Union, active from 1951 until the dissolution of the Soviet Union in 1991.
Universal RocketThe Universal Rocket or UR family of missiles and carrier rockets is a Russian, previously Sovietrocket family. Intended to allow the same technology to be used in all Soviet rockets, the UR is produced by the Khrunichev State Research and Production Space Center. Several variants were originally planned, of which only three flew, and only two of which entered service. In addition, the cancelled UR-500 ICBM formed the basis for the Protoncarrier rocket.
Expendable launch systemAn expendable launch system (or expendable launch vehicle/ELV) is a launch vehicle that can be launched only once, after which its components are destroyed during reentry or impact with Earth, or discarded in space. ELVs typically consist of several rocket stages that are discarded sequentially as their fuel is exhausted and the vehicle gains altitude and speed. During the Space Race, all launch vehicles were expendable.List of Proton launchesAs of 12 February 2026, rockets of the UR-500 / Proton family have accumulated 431 launches since 1965, 383 of which were successful, yielding an 88.9% success rate.
Russian languageRussian is an East Slavic language belonging to the Balto-Slavic branch of the Indo-European language family. It is one of the four extant East Slavic languages, and is the native language of the Russian people. Russian was the de facto (and de jure in its final years) official language of the former Soviet Union.
ProtonA proton is a stable subatomic particle, symbol p, H, or H with a positive electric charge of +1 e (elementary charge). Its mass is slightly less than the mass of a neutron and approximately 1836 times the mass of an electron (the proton-to-electron mass ratio). Protons and neutrons, each with a mass of approximately one dalton, are jointly referred to as nucleons (particles present in atomic nuclei). One or more protons are present in the nucleus of every atom.
United States Department of DefenseThe United States Department of War (DoW), previously referred to as the Department of Defense (DoD), is an executive department of the United States federal government charged with coordinating and supervising the United States Armed Forces—the Army, Navy, Marines, Air Force, Space Force, and, for some purposes, the Coast Guard—and related functions and agencies.
Sheldon namesSheldon names were used to identify launch vehicles of the Soviet Union when their Soviet names were unknown. The system was published by Dr. Charles Sheldon of the United States Library of Congress in 1968. The system emphasizes the basic families of launch vehicles with special indicators for variants within a family. A typical Sheldon name is the F-1-m, a forerunner to the Tsyklon launch vehicle, or the F-2.
Hypergolic propellantA hypergolic propellant is a rocket propellant whose components spontaneously ignite upon contact with one another. In contemporary usage, the term typically refers to the combination of dinitrogen tetroxide (an oxidizer) and one of the various forms of hydrazine (a fuel). Advantages of hypergolic propellants include their ability to be stored at room temperature and their ability to be reliably and repeatedly ignited without a separate ignition system.
Main Missile and Artillery DirectorateThe Main Missile and Artillery Directorate, commonly referred to by its transliterated acronym GRAU (ГРАУ), is a department of the Ministry of Defence of Russia responsible for the military acquisition and equipment of the Russian Armed Forces. It is subordinate to the Chief of Armament and Munition of the Russian Armed Forces, a vice-minister of the Ministry of Defence. The GRAU was established in 1862 to provide equipment and training for the Imperial Russian Army.
Literal translationLiteral translation, direct translation, word-for-word translation, word-by-word translation, or word-to-word translation is the translation of a text done by translating each word separately without analysing how the words are used together in a phrase or sentence. In translation theory, another term for literal translation is metaphrase (as opposed to paraphrase for an analogous translation).*As an Amazon Associate I earn from qualifying purchases.