|UR-700 - UR-700 Launch Vehicle for Direct Lunar Landing Mission|
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The UR-700 was the member of Vladimir Chelomei's Universal Rocket family designed to allow direct manned flight by the LK-700 spacecraft to the surface of the moon. The basic configuration of the UR-700 was established in January 1962 as part of the UR-500 Proton draft project. However Korolevís N1 was the selected Soviet super-booster design. Only when the N1 ran into schedule problems in 1967 was work on the UR-700 resumed. The draft project foresaw first launch in May 1972. But no financing for full scale development was forthcoming; it was apparent that the moon race was lost.
The complete UR-700 / LK-700 system would have had a height of 76 m, a diameter of 17.6 m, and a gross lift-off mass of 4,823 tonnes. The payload capability was 151 tonnes into a 200 km earth orbit or 50 tonnes on a translunar trajectory. The UR-700 consisted of first and second stages mounted to the core in parallel, while the upper stages, based on the UR-500 Proton, were arranged in tandem in the core. The first stage consisted of six 4.15 m diameter modules in pairs; and the second stage of three modules. A single RD-270 engine was used in all nine modules.
TsKBM began work on the UR-700 launch vehicle in 1962. Variants were studied with 70 to 175 tonnes payload, and rocket stages of various thrust levels, including nuclear stages. The conclusion was reached that a direct lunar landing would require a payload of 130 to 170 tonnes. Principles of the final design were:
The configuration of the UR-700 was driven by the requirement that its components be rail-transportable and modular. In this way the launch vehicle could be built and completely tested at the Khrunichev factory in Moscow and then quickly assembled for launch at the Baikonur cosmodrome in Kazakhstan. Chelomei's solution was to use a basic module of the largest possible rail-transportable diameter (4.15 m diameter and a sphere radius of 2.265 m at the base). This could consist of an oxidiser tank, or a fuel tank with the engine installation. The design had to meet requirements from two sides. On the one hand, the maximum length and diameter of the modules was dictated by the size of rail wagons and platforms, and existing rail tunnels, waterways, and turntables. On the other hand, the size of the rocket stage, and its corresponding volume and mass, were driven by the necessary technical characteristics of the UR-700. The UR-700 requirements greatly affected the design of the UR-500 Proton, since the Proton core stages would form the basis of the UR-700 modules and upper stages.
The basic configuration of the UR-500, taking into account the UR-700 requirements, was selected in January 1962. While approval to proceed with development of the UR-500 came in April 1962, no such go-ahead was received for the UR-700. However Glushko was authorised to proceed with development of the enormous RD-270 engines required for the UR-700. Chelomei unveiled his UR-700 project to Khrushchev at a meeting at Baikonur in September 1964, during which he showed a model of the rocket to Khrushchev. Korolev was also present at the meeting, and a decision was taken to examine the potential of the proposal. Unfortunately for Chelomei, Khrushchev was ousted from power a month later, and all of his projects came under scrutiny by the new regime.
The next chance for the project to be considered came on 16 November 1966, when a Keldysh-headed expert commission considered the state of the N1 programme. Korolev had died earlier in the year, and once again Glushko, Chelomei, and Yangel advocated development of the UR-700 or R-56 in lieu of the N1. While it was agreed that engine development and studies of these launch vehicles could continue, the government decree issued approved Mishin's draft plan for the first lunar landing using the N1.
Chelomei signed the UR-700 design directive documents on 21 July 1967. Development of the UR-700 was undertaken in accordance with decree 1070-363 of the Soviet Ministers and Central Committee of the Communist Party on 17 September 1967 and MOM decree 472 of 28 September 1967. Study index number 4855CC by TsNIIMASH in 1966 showed that any development of improved versions of the N1 would be practically equivalent to design and qualification of a new rocket, while the UR-700 modular approach allowed a range of payloads without requalification. The UR-700/LK-700 combination could support the DLB lunar base better, as well as Venus/Mars manned flybys and Mars landing expeditions.
Project plan was as follows:
Following the explosion of the first N1 in January 1969, Pilyugin was called to a meeting at the Kremlin. Chelomei was again proposing the use of his UR-700 in the place of the N1, and a flight to Mars using an even larger version of the launch vehicle. Afanasyev was preparing a decree along these lines. Pilyugin refused to participate in this 'adventure'. Everyone thought that the UR-700/LK-700 project represented a duplicative effort from the beginning.
Tyulin was less concerned about the UR-700. He noted that Mishin was deep into the development of the N1, and the UR-700 was only being discussed as being promoted as a draft project. The original UR-700 documents had been sent to archives in 1964 when the N1-L3 was approved. At a reception shortly thereafter, Chelomei told Chertok that if the UR-700 had been selected instead of the N1, Russia would already be on the moon. Three stages of the UR-700 had already been developed and flown as the UR-500 Proton. Only the RD-270 engines of the first stages would have to have been developed. The configuration of the UR-700 for the lunar mission consisted of 9 RD-270's with 5760 tonnes thrust at sea level. This would have delivered 140 tonnes into low earth orbit.
|UR-700 Profile - UR-700 Launch Profile. At liftoff, nine engines - six on the six outer stage 1 modules, and three on the three core modules - fired. During the stage 1 burn, the three engines of the core modules were fed by propellants in forward tanks of the outer six modules. Therefore the Stage 2 core burn started with full tanks in the core modules. Stage 3, a modification of the Proton first stage, placed the 151 tonne LK-700 spacecraft into a 200 km earth parking orbit.|
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Nevertheless Chelomei's bureau continued to study a number of different ways of clustering the basic modules until 1974, when the project was finally and definitively suppressed.
The RKS Rocket-Space System was designed for direct landing on the moon without docking in earth or lunar orbit. It consisted of:
The UR-700 consisted of first and second stages mounted to the core in parallel, while the third and fourth stages were arranged in tandem in the core. The first stage consisted of six 4.15 m diameter modules in pairs; the second stage of three 4.15 m modules; the third of a core 4.15 m module with three 1.6 m diameter tanks.
The RD-270 engine was used in all nine modules of the first and second stages, operating at 103% thrust at lift-off. At lift-off all nine RD-270 engines would fire; the engines of the second stage would feed from propellant tanks in the forward section of the first stage modules. Therefore at separation of the six first stage modules, the propellant tanks of the three second stage modules would still be full. In one variant of the design, each module of the first and second stages would have only one propellant tank, instead of separate oxidiser, fuel, and stage two propellant tanks. A cross-feed system would be used to feed all engines from all tanks. This would result in a more complex but lighter system with improved propellant utilisation. Solid rocket motors were used to separate the modules at an angle of 15 to 20 degrees upon propellant depletion.
|UR-700 Cutaway - UR-700 lunar landing launch vehicle - From left: cutaway and bottom views; cutaway of core vehicle after six external stage one modules and shrouds were jettisoned; external view. The cutaway shows the arrangement of N2O4 oxidiser tanks (green) and UDMH fuel tanks (orange). The six outer 4.1 m diameter modules contained fuel and oxidizer tanks for stage 1 and fuel or oxidiser tanks for the three core modules. After propellant depletion, the six outer modules would separate, leaving the three core modules to continue their burn. The third stage, based on the Proton first stage, placed the LK-700 spacecraft into a 200 km earth orbit. The LK-700 was equipped with four nearly identical clustered stages and a lunar landing/ascent stage. The three outer stages fired to place the spacecraft on a translunar trajectory. The inner core stage was used for midcourse corrections, braked the spacecraft into lunar orbit, and then again until it was just above the lunar surface. The ascent stage performed the final soft landing on the moon and then, using the landing legs as a launch platform, launched the LK-700 capsule back towards the earth.|
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The third stage was adapted from the Proton UR-500 first stage. The overall stage was 80% of the mass of the Proton first stage, but with only three external tanks and three engines in place of the six larger-diameter tanks and engines of the Proton. The 4.15 m diameter core tank was shortened a bit compared to the Proton, and the three 2.0 m diameter external tanks lengthened. The three RD-254 engines were versions of the UR-500's RD-253 with high-altitude nozzles. Loads were transmitted from the second to the third stage using three conical structures. The third stage was equipped with ullage engines to provide enough G forces after separation from the second stage to allow propellants to settle and the three main engines to start
The UR-700's guidance system was by KBEM MOM and used digital computers. The booster was manoeuvred using gimballed engines. The gimbal actuators were by TsNIIAG. The RD-270 engines on the first stage could be gimballed 8 degrees outward, the third stage engines 3 degrees.
The rocket blocks were connected using a coupling system developed by KB Arsenal. The rocket blocks were connected together at four places: at the top of the engine section, where the main loads were transmitted, at the intertank section, at the top of the block, and at the location of the crossfeed propellant lines. NIIP MAP developed the SOB system of expendable tank support and KSURT complex propellant utilisation system. At first stage separation these systems changed over the gas and pneumatic systems, shutdown the propellant valves, and triggered the pyrotechnics for stage separation. The second stage used the SKU propellant utilisation system developed for the UR-500.
The UR-700 and LK-700 would be assembled at the existing technical positions of the N1 launch complex. However KBOM did design a launch complex for the UR-700 if the decision was taken to build a dedicated launch site. On the pad the UR-700 would be connected using triple umbilical lines.
Missions and Payloads
The draft project selected a preferred launch vehicle configuration using RD-270 engines, delivering 150 tonnes in low earth orbit, which could place two cosmonauts on any point of 88% of the visible lunar surface.
|RD-270 - RD-270 Rocket Engine - largest single-chamber engine ever developed in the Soviet Union.|
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|RD-0410 NTP Engine - RD-0410 Nuclear Thermal Engine|
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The later DLB lunar base would require 80 tonnes per year of payload delivered to the surface starting in 1975, followed by 150 tonnes per year after 1980. Versions of the UR-700/LK-700 could handle this more easily than modifying the N1. Later versions of the UR-700 could use high energy propellant or nuclear-powered upper stages
Lunar versions of the Almaz OPS would be placed in lunar orbit to conduct detailed reconnaissance of the surface using manned assistance. The OPS would also be used as a command post to co-ordinate the work of lunar surface operations and organise rescues in the case of emergencies on the surface.
The TsNIIMASH study recommended the UR-700 over the N1 for these later operations. The UR-700 would also be used for:
|LK-700 - Appearance of the LK-700 spacecraft at each phase of its direct lunar landing mission.|
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LEO Payload: 151,000 kg. to: 200 km Orbit. at: 51.0 degrees. Payload: 50,000 kg. to a: Translunar trajectory. Liftoff Thrust: 5,760,000 kgf. Total Mass: 4,823,000 kg. Core Diameter: 17.6 m. Total Length: 76.0 m.
Chelomei's TsKBM began work on the UR-700. The conclusion was reached that a direct lunar landing would require a payload of 130 to 170 tonnes. Initial LK-700 spacecraft designs were derived from the 'Raketoplan' family of manned modular space vehicles. Korolev's N1-L3 design was selected in 1964 for the manned lunar landing, but the UR-700 would surface again when the N1 encountered delays.
The RD-270 engine was proposed for Chelomei's UR-700 and Yangel R-56 lunar landing launchers in competition to Korolev N1. The RD-270 was in the same class as the F-1 engine developed for America's Saturn V launch vehicle, but burned storable but toxic propellants.
Following the August decree that gave the circumlunar project to Chelomei and the lunar landing project to Korolev, further work on development of the UR-700 by Chelomei was cancelled. However development of the RD-270 engine was continued and Chelomei continued to do UR-700 design studies.
Ministry of General Machine Building (MOM) Decree 'On approval of work on the draft project of the UR-700/LK-700 lunar complex' was issued.
Military-Industrial Commission (VPK) Decree 'On creation of a commission to compare the UR-700-LK-700 and the N1-L3' was issued.
Mishin's draft plan for the Soviet lunar landing was approved by an expert commission headed by Keldysh. The first N-1 launch was set for March 1968. At same meeting, Chelomei made a last ditch attempt to get his revised UR-700/LK-700 direct landing approach approved in its place. Although Chelomei had lined up the support of Glushko, and Mishin was in a weak position after Korolev's death, Keldysh managed to ensure that the N1-L3 continued. However continued design work on the LK-700, the UR-700 booster, and development of the RD-270 engine were authorised.
Chelomei's TsKBM began work on the UR-700 launch vehicle for manned lunar landing missions in 1962. Chelomei took a sound conservative design approach (i.e. no docking required, no cryogenics).
Development of the LK-700 manned lunar landing spacecraft was undertaken in accordance with decree 1070-363 of the Soviet Ministers and Central Committee of the Communist Party on 17 September 1967 and MOM decree 472 of 28 September 1967. Study index number 4855CC by TsNIIMASH in 1966 showed that any development of improved versions of the N1 would be practically equivalent to design and qualification of a new rocket, while the UR-700 modular approach allowed a range of payloads without requalification. The UR-700/LK-700 combination could support the DLB lunar base better, as well as Venus/Mars manned flybys and Mars landing expeditions. Work would continue through the mock-up stage until 1974.
Further development work on the RD-270 engine, UR-700 launch vehicle, and LK-700 lunar landing project are cancelled following the successful Apollo lunar landing.
As the only remaining contender for the Aelita design competition, Chelomei proposes a Mars flyby using an MK-700 spacecraft. A crew of two would be sent on a two year mission in a single launch of a UR-700M booster. The spacecraft would have a mass of 250 tonnes in low earth orbit and be equipped with an RD-410 nuclear engine.