The first cosmonauts to the moon

In the course of the mid-1960s, the Soviet Union built the equipment it required for manned lunar exploration. This comprised the Proton rocket, to fly spacecraft around the moon, and the N-1 rocket, designed to land cosmonauts on the moon. The Soviet Union built the spacecraft necessary to circle and land on the moon: the Zond to pass round the moon and return to Earth, the LK lunar lander and the LOK lunar orbiter. And, finally, the Soviet Union trained a squad of cosmonauts to fly there and land there. Each is described in turn.

THE ROCKET FOR CIRCLING THE MOON: THE UR-500K PROTON

The UR-500 Proton rocket dates to October 1961, when Russia detonated, over the northern Arctic island of Novaya Zemlya, its first 58-megatonne thermonuclear superbomb. This bomb was carried aloft and dropped by a Tu-95 bomber, but there was no way these ageing propellor planes were going to reach, never mind drop their cargoes on New York. For this purpose, a new, powerful rocket was required. Nikita Khrushchev turned to Vladimir Chelomei, the man who gave him his military rocket fleet who now promised to build him an ever bigger rocket called the Universal Rocket 500, so-called because it could be used for many other purposes (hence UR-500) [1]. Not long afterward, Khrushchev was bragging about the Soviet Union’s new ‘city – buster’ rocket.

In the event, the UR-500 was never taken into the armaments as a city-buster and was cancelled as a military project very early during the Brezhnev government. The UR-500 survived and was converted to civilian use. Vladimir Chelomei astutely persuaded the Kremlin that the UR-500, with suitable upper stages, could send a small manned spacecraft round the moon and that this was a much quicker, neater way of doing so than Sergei Korolev’s Soyuz complex, without any of the uncertain­ties of Earth orbit rendezvous. As a lunar rocket, it was called the UR-500K.

Proton rocket

Chelomei’s moon rocket was a three-stage booster carrying nitrogen tetroxide and unsymmetrical dimethylmethylhydrazine (UDMH), the fuel abhorred by Korolev. The engine of the first stage was built by Valentin Glushko’s OKB-456 and became the famous RD-253 engine. The second – and third-stage engines were built by the Kosberg Design Bureau. The Proton had the most advanced rocket engines in the world for 20 years. Valentin Glushko’s RD-253 engines recycled their exhaust gases to create a closed-circuit turbine system. Pressures of hundreds of atmospheres were obtained on delivery. Each engine weighed a modest 1,280 kg. The turbines went round at a fantastic 13,800 revolutions a minute or 18.74 MW. Temperatures reached 3,127°C in the engine chambers and their walls were plated

RD-253

with zirconium. OKB-456 developed the first three stages, but the fourth came from rival Korolev’s design bureau. Here, block D was developed by Mikhail Melinkov in OKB-1 [2]. This relied on the traditional liquid oxygen and kerosene that was the hallmark of Korolev’s approach.

The RD-253 was perhaps the greatest breakthrough represented by the Proton. Equally significant was the clustering of fuel tanks of the side of the bottom stage.

Russian rockets are limited to a diameter of 4.1 m, the widest size that can be trans­ported by the rail system. This restriction would make any powerful rocket far too slim to be viable. What Chelomei did was develop the main core as the oxidizer only, within the 4.1m limit and later attach the fuel tanks to the side of the rocket. They were built separately, transported separately from Moscow to Baikonour and then attached in finishing hangars beside the pad in Baikonour. With the tanks attached, the diameter of the Proton on the pad is 7.4m.

Launching the Proton required the building of fresh pads to the northwest of the cosmodrome. Two sets of double pads were built, called Area 81 and Area 200. Each had a left pad and a right pad (81L, 81P, 200L, 200P). A Proton is brought down to the pad on a train trailer and then erected into the vertical position. Around the pad are 100 m tall lightning conductors and four 45 m tall floodlight stands. A shallow flame trench takes away the rushing roar of the engines firing at take-off from both sides.

Proton was and still is built in the Fili plant in Kaliningrad, now known as Korolev. This was an old automobile factory, taken over by the Bolsheviks to build German Junkers planes in the 1920s and then Tupolevs. It became effectively part of Vladimir Chelomei’s OKB-52 in 1960 but is now known as Khrunichev, an affiliate of Lockheed Martin.

The design history of the Proton is, compared with that of the N-1 which follows, not well known. It took Chelomei and his OKB-52 fewer than two years to design the UR-500 (1961-3) and fewer than two years to build it (1963-5), all the more remark­able granted its cancellation as a military weapon. The design was subject to rigorous ground testing and Chelomei refused to rush things. This paid off, for the UR-500’s first mission went like a dream, lofting the first of a series of four large cosmic ray satellites over 1965-8. They were called Proton and the first, Proton 1, was the largest scientific satellite ever launched up to that point, weighing in at no less than 12 tonnes (as a satellite, it was a failure, but that was not the launcher’s fault). Of the Proton’s first four launchings, only one failed, making it the most promising rocket of its day. The first launch was well publicized. The Western media quickly recognized a rival to the American Saturn IB moon rocket and came hastily but correctly to the immediate conclusion that an early task for the rocket was to send a Russian around the moon first. Possibly because of its military origins, the Russians kept back details of the Proton for well over 20 years and the first proper pictures of a Proton launch were not released until the 1980s.

Despite its promising start and despite Chelomei’s thoroughness, the Proton was to have an exasperating development history. The early promise was not maintained, and of its first 29 launches, no less than 14 failed, arguably costing the Soviet Union the round-the-moon race, as well as numerous lunar and Mars probes. At the time, nobody would have credited it that the Proton would go on to become one of the most reliable rockets in the world. Proton was launched for the 300th time in June 2003. Although there were occasional final-stage failures with block D, lower-stage failures became most unusual (there were two in the 1990s, when quality control in the manufacturing plant slipped during the period of greatest economic difficulty). A new version of the Proton was even introduced, the Proton M, in 2001.

Russia’s UR-500K Proton

Length 44.34 m

Diameter 4.1 m

First stage (block A) Length 21 m Diameter with tanks Engines Burn time Thrust Fuels Design 4.1 m 7.4 m Six RD-253 130 sec 894 tonnes UDMH and N204 OKB-456

Second stage (block B) Length 14.56 m Diameter Engines Burn time Thrust Fuels Design 4.1 m Two RD-210, one RD-211 300 sec 245 tonnes UDMH and N204 0KB-456

Third stage (block V) Length 6.52m Diameter Engines Burn time Thrust Fuels Design 4.1 m Three RD-213, one RD-214 250 sec 64 tonnes UDMH and N204 0KB-456

Fourth stage (block D) Length 2.1 m Diameter Engine Thrust Length Diameter Fuels Design 4.1 m One 11D58M 8.7 tonnes 6.3 m 3.7m Liquid oxygen and kerosene 0KB-1