|astronautix.com||Soviet Manned Lunar Projects Part 1|
|Soviet Lunar Landers|
Comparison of Soviet lunar lander designs. Only the LK reached the hardware stage.
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The First Lunar Projects
The first official plan for future Soviet spaceflight was contained in a decree of 30 January 1956. This set forth the following objectives:
The first approach to the rather vague last objective was to use nuclear power - a nuclear reactor heating ammonia propellant. Korolev's OKB-1 completed a draft project for three variants of rockets using such a propulsion system. The third variant designed was a 'Super Rocket' with a lift-off mass of 2,000 tonnes and a payload of 150 tonnes. This was a true antecedent of the later N1 moon rocket. The first and second stages were in the conical 'raketov' form later adopted for the N1. The first stage used a massive cluster of Kuznetsov NK-9 engines each with a thrust of 52 tonnes. The second stage used four nuclear engines with a total thrust of 850 tonnes. Operating at a temperature of 3500 degrees K a specific impulse of 550 seconds in vacuum using ammonia propellant was expected. A mixture of liquid hydrogen and methane was considered as a better-performance propellant at a later date. Although ideal for use in nuclear rockets, use of liquid hydrogen as a propellant was not considered technically possible in the short term.
|L1-1963 - Cutaway view of 1963 L1 circumlunar spacecraft.|
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The L1 - by R-7 to the Moon - 1959 to 1963
Korolev had designed the Vostok manned spacecraft that gave Russia the lead in the space race in the first half of the 1960's. Studies for a follow-on to Vostok, with the objective of sending a manned capsule on a circumlunar flight, began in 1959 under Tikhonravov. At this point it was assumed that any such flight would be at an early date and require use of launch vehicles derived from Korolev's R-7 ICBM. Since planned derivatives of the R-7 could not put more than six tonnes into orbit, it was immediately obvious that a circumlunar spacecraft would have to be assembled in low earth orbit from several R-7 launches. Therefore it would be necessary to perfect techniques for rendezvous, docking, and refuelling of rocket stages in orbit. By 1960 to 1961 the studies, now dubbed 'L1', were expanded to cover automatic rendezvous and docking of several stages, and use of manipulators to assemble the stages.
Meanwhile the configuration of the re-entry vehicle for a Vostok follow-on was being investigated by other sections of Korolev's bureau. Lead for work on the re-entry problem was Section 11. There was no shortage of ideas. In 1959 Chief Designer Tsybin of OKB-256 and Solovyev of OKB-1 Section 9 both offered designs for a winged manned spacecraft with a hypersonic lift-to-drag ratio of over 1.0. Prugnikov of Section 8 and Feoktistov of Section 9 proposed development of a ballistic capsule composed of variations of 'segmented spheres'.
|L2-1963 - 1963 L2 robot lunar rover spacecraft. L2 configuration speculative based on early Ye-8 rover design studies at OKB-1.|
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To exploit this database, Reshetin started a project group to conduct trade-off studies of the various configurations at the beginning of 1960. The government decree 715-296 of 23 June 1960 'On the Production of Various Launch Vehicles, Satellites, Spacecraft for the Military Space Forces in 1960-1967' included authorisation for Korolev to develop draft projects on themes KS (heavy manned spacecraft, 2-3 crew, to demonstrate rendezvous, docking, and controlled flight, to be developed in 1961 to 1963) and KL (manned spacecraft for lunar flyby - to be developed in 1961 to 1964). The work was therefore upgraded to a project sector, under the leadership of Timchenko, in 1961.
|L3 -1963 - 1963 L3 manned lunar lander using earth-orbit rendezvous method. Configuration based on description and lander configuration of early L3M design.|
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These studies were the most complex ever undertaken, and Korolev obtained assistance from the most brilliant Soviet aerodynamicists, notably Likhushin at NII-1, and those refugees from Chelomei's take-over of their bureaux, Myasishchyev at TsAGI, and Tsybin at NII-88. In 1962 the classic Soyuz 'headlight' configuration was selected: a hemispherical forebody transition in a barely conical (7 degree) section to the section-of-a-sphere heat shield.
|L4 -1963 - 1963 L4 manned lunar orbiter.|
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This configuration was selected only after considerable engineering angst. From the point of view of pulling the capsule away from the rocket in an emergency, positioning the capsule at the top of the spacecraft was ideal. But to use this layout with the living module concept, a hatch would have to be put through the heat shield to connect the two living areas. Korolev's engineers just could not accept the idea of violating the integrity of the shield (and would later get in bitter battles with other design bureaux when competing manned spacecraft - Kozlov's Soyuz VI and Chelomei's TKS - used such hatches).
|L5 -1963 - 1963 L5 manned lunar rover. Drawing based on model at Tsniimash museum.|
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The end result of this design approach was remarkable. The Apollo capsule designed by NASA had a mass of 5,000 kg and provided the crew with six cubic meters of living space. A service module, providing propulsion, electricity, radio, and other equipment would add at least 1,800 kg to this mass for the circumlunar mission. The Soyuz spacecraft provided the same crew with nine cubic meters of living space, an airlock, and the equipment module for the mass of the Apollo capsule alone!
|N1-L3 Tower - Detail of tower of N1-L3 7L|
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Although only Korolev was authorised to do draft project work on lunar themes, the other Chief Designers pursued alternate approaches. Chelomei was Korolev's arch-rival, and had the advantage of having Nikita Khrushchev's son in his employ. He was said to have been ordered informally by Khrushchev on 13 May 1961 to begin development of a manned circumlunar spacecraft in response to the American Apollo program. This would be launched by his UR-500 rocket, already being designed as authorised in the same June 1960 decree that started work on Soyuz. The advantage of using the UR-500 was that a manned spacecraft could be launched around the moon in a single launch, as opposed to the complex earth-orbit assembly techniques being refined by Korolev. Funds for design work on the LK-1 were available from the Kosmoplan and Raketoplan projects. These were lifting-body unmanned and manned vehicles being designed by Chelomei for a range of military and planetary exploration missions as per the June 1960 decree.
The first 1961 draft of the Soyuz project (codes KS, KL, and Vostok-Zh of the 1960 decree) would exploit the modernised Vostok-Zh. Three rocket stages would be assembled in low earth orbit using a manned Vostok tug. They would then launch a Soyuz capsule on a lunar flyby and return to earth.
|N1 engineers - N1 engineers study drawing|
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Korolev understood very well that financing for a project of this scale would only be forthcoming from the Ministry of Defence. Therefore his draft project proposed two additional modifications of the 7K: the Soyuz-P space interceptor and the Soyuz-R command-reconnaissance spacecraft. The VVS and the rocket forces supported these improved variants of the Soyuz.
To Korolev's frustration, while Kozlov's OKB-1 Filial 3 in Samara received budget to develop the military Soyuz versions, his own circumlunar Soyuz-A was not included in the space program of the USSR. The 7K-9K-11K plan would have required five successful automatic dockings to succeed. This seemed impossible at the time. Chelomei's LK-1 single-manned spacecraft, to be placed on a translunar trajectory in a single launch of his UR-500K rocket, was still the preferred approach. But even Chelomei had no official authorisation to undertake actual detailed design and development of the spacecraft or booster.
|N1 Engine fired - N1 Engine fired on test stand|
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Even while attempting to obtain approval for his modest R-7-launched L1 circumlunar spacecraft, Korolev was attempting to sell more ambitious schemes using his N1 super-rocket. The space race with the Americans had heated up considerably since the promulgation of the casual program of 1956. In a letter to the Central Committee of the Communist Part in January 1960 Korolev proposed an aggressive program for Communist conquest of space. This would be accomplished by development of a new rocket of 1,000 to 2,000 tonnes gross lift-off mass with a 60 to 80 tonne payload at the earliest possible date. Among the potential payloads for his rocket in the period 1963 to 1965 Korolev proposed a spacecraft with 2 to 3 men for flyby of the moon, entry into lunar orbit, and return to earth. Payload mass would be 10 to 12 tonnes in lunar orbit with 2 to 3 tonnes return payload. This lunar orbiter would be twice as large as the L1 'loop around the moon' spacecraft. Korolev pledged to place before the Central Committee in the third quarter of 1960 comprehensive plans for development of the new projects.
This letter was followed by a meeting with Khrushchev on the subject on 3 March 1960. Korolev believed it would be truly possible with backing from the very top to have a large rocket in the USSR in a very short span of time. Unfortunately at the meeting Korolev made a slip of the tongue he would always regret, admitting that his plan had not been agreed among all of the Chief Designers. This resulted in Khrushchev throwing the matter back for a consensus plan.
|N1 Upper Stage - N1 Upper Stage firing on test stand|
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|N1 6L Liftoff|
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Note that although completion of draft projects for the N1 and L1 were authorised, no work on a N1-launched lunar landing or lunar orbiter spacecraft was included. Therefore only N-I and L1 design work officially began as a result of the final government decree 715-296 of 23 June 1960 'On the Production of Various Launch Vehicles, Satellites, Spacecraft for the Military Space Forces in 1960-1967'.
|N1 6L ignition|
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Although only Korolev was authorised to do draft project work on lunar themes, the other Chief Designers pursued other approaches. Aside from Chelomei's LK-1 circumlunar spacecraft, the Yangel and Chelomei bureaux developed alternate booster designs (Yangel's was designated R-56 and Chelomei's was the UR-700). Both used clustered 4 m diameter rocket stages, equipped with a single large Glushko engine, using toxic storable propellants, with a thrust of 450 to 550 tonnes. Such stages could be built in factories in Moscow or Dniepropetrovsk and shipped on the existing Soviet rail system to Baikonur for final assembly.
The N-I draft project was completed on 16 May 1962. The design was defended before the other Chief Designers on 2 to 16 July 1962. Among the design objectives of the three stage N-I were:
|N1 6L Engine Start|
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The expert commission supported the draft project. But the programme was still without an authorised mission. At a meeting between Khrushchev and the Chief Designers at Pitsunda in August, Khrushchev ordered start of a project to put a 75 tonne manned platform with nuclear weapons into low earth orbit. This was the initial payload; the official decree authorising N-I production was issued on 24 September 1962 with first flight to occur in 1965. After two years of struggle, Korolev finally had his authorisation to build a moon rocket - but not a spacecraft for it.
This did not stop Korolev from fleshing out the ambitious lunar plans set out in the draft project and trying again for approval. On 23 September 1963 Korolev submitted his plans for space projects in the period 1965 to 1975. He now saw a clear chance to again appeal to the leadership for a manned lunar landing program. He dusted off his rejected L-1 circumlunar project, and added four new spacecraft that would allow reconnaissance, followed by landing on the moon and extended exploration of its surface.
|N1 7L Liftoff|
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This revision to the original L1 project of 1962 had the same objective of sending two men on a circumlunar flyby trajectory. But now the Soyuz had a reverse configuration of that used earlier. From fore to aft, the modules were: the Descent Capsule (SA), Living Module (BO); Equipment Module (AO); Propulsion Module (AO); Rendezvous electronics module (NO) and Docking Unit (SU). This configuration would be important in the later N1-based projects. As before, the system consisted of the 7K manned spacecraft, the 9K rocket spacecraft, and the 11K tanker. A total of six launches of the 11A511 Soyuz booster would be required. The 9K rocket stage would be put in orbit first. It would be followed by four 11K tankers which would top off the tanks of the rocket block. Then, when all was ready, the 7K manned craft would be put into orbit and dock with the 9K stage. The stage would fire and put the manned spacecraft on a translunar trajectory.
The 7K would be equipped with cinema cameras and scientific sensors to record the lunar surface during the flyby, which would be at from 1,000 to 20,000 km from the lunar surface. Total flight time was 7 to 8 days. The SA would separate from the 7K at 120 to 150 km altitude and re-enter the earth's atmosphere at 11 km/sec. After decelerating to subsonic speed, the SA's parachute would open at 10-18 km altitude. Total mass of the L1 in low earth orbit was 23,000 kg and the flyby mass of the Soyuz alone was 5,100 kg.
|N1 MIK Assembly Hall|
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The L2 was a project to land a remote-controlled self-propelled rover on the surface of the moon. It would use the same rocket stage and tanker elements developed for the L1 manned circumlunar project. It can be seen to be the direct ancestor of the Ye-8 Lunokhod lunar rovers of the 1970's.
The objective of the L-2 would be to conduct scientific research on the lunar surface and to allow selection of a favourable landing point for later manned flights. A television system would send back panoramic television pictures. The rover would be nuclear-powered and equipped with a radio beacon for later manned expeditions to home on for precision landings. It would also investigate:
The L-2 system consisted of:
|N1 Model Test|
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Total mass of the L-2 + 13K + 9K complex at ignition of the 9K for translunar injection was 23,000 kg. Total mass of the L-2 and 13K in their translunar cruise configuration was 5,000 kg. As was the case for the L-1, six launches of the Soyuz 11A511 booster would be required to assemble the L-2 in a 225 km low earth assembly orbit.
Korolev's first version of the L-3 manned spacecraft was designed to make a direct lunar landing using the earth orbit rendezvous method. It was a 200 tonne spacecraft requiring three N1 launches and a single Soyuz 11A5ll launch to assemble in low earth orbit. The first N1 launch would place the 75 tonne partially-fuelled TLI stage and L3 spacecraft (except the L1 manned return craft) into low earth orbit. Two further N1 launches would orbit 75 tonne tankers which would rendezvous and dock with the first payload and top off its propellant tanks. Then the Soyuz would be launched for an automated rear-end docking with the entire L3 stack. The L3 spacecraft thereby assembled consisted of:
|N1 Wind Tunnel Test|
Credit: RKK Energia. 9,093 bytes. 320 x 240 pixels.
The L3 was not authorised in this form and it would over two years before a very belated start was made to beat the Americans in the moon-landing race. The L3 reformulated for the crash program would require only a single uprated N1 launch and use the lunar-orbit-rendezvous method, with a single-man lander.
|N1 Subscale Model|
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The L-4 Manned Lunar Orbiter Research Spacecraft would have taken two to three cosmonauts into lunar orbit for an extended survey and mapping mission. The L-4 complex, with a total mass of 75 tonnes, would be placed into orbit in a single N1 launch, and would consist of:
The L-5 Heavy Lunar Self-Propelled Craft would be used for extended manned reconnaissance of the lunar surface. With a maximum speed of 20 km/hour, it would provide living accommodation for three cosmonauts and 3,500 kg of provisions. The crews themselves would be landed on the moon using the L-3 complex.
|Model of N1 pad|
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At the beginning of 1964, despite hard work in the previous year, it was apparent that there were still one to two years of development and construction to go and the target dates set in the decree would not be met.
On 24 March 1964 Korolev managed another meeting with Khrushchev, where he again advocated an aggressive plan of lunar and interplanetary exploration. He dusted off his old L3 lunar landing scheme. Two variants of the L3 would be developed: the basic version would use Lox and Kerosene in Rocket Blocks G and D, with N2O4/UDMH in Block E. A later version would use Lox/LH2 in all of these upper stages. This would add 4 tonnes to the lunar surface payload. Korolev promised to have an L3 draft proposal completed in 1964 and the spacecraft in service by 1966. Development of the Lox/LH2 engines would take place from 1964 to 1967. He even pressed development of the TMK / TMK-E interplanetary manned spacecraft, using the newest designs from his bureau with nuclear electric engines. Khrushchev expressed some interest now in the lunar landing scheme, in the face of the American's evident determination to press on with project Apollo.
Feeling he had Khrushchev's support, Korolev on 25 May 1964 drafted a letter to Brezhnev, then in charge of missile development. Korolev complained of the delays in the N-I due to lack of priority and financing. He noted that of 11 million roubles budgeted for construction of the launch complex in1964, only 7 million had been received. Two years after authorisation ,work on the guidance systems had not even begun, due to the priority of military projects. Korolev tried to put the screws to Brezhnev by noting that Khrushchev had always sponsored scientific projects, and that with the Saturn I rocket the Americans had already surpassed the Americans in the booster race. He also attempted to sabotage Chelomei's LK-1 circumlunar project yet again, by noting that he was wasting his time with Glushko's 'low energy' propellants and that a single launch of his N-II could put a Soyuz modification on the same mission.
|N1 Rollout - N1 Rollout - base of booster|
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The LK-1 - by UR-500K around the Moon - 1964 to 1965
On 3 August 1964 Command number 655-268 issued by Central Committee of Communist Party authorised both Chelomei and Korolev to proceed with development and production of their respective moon projects.
Chelomei was permitted to develop his three-stage UR-500K launch vehicle and the LK-1 circumlunar spacecraft. Thanks to the informal work done in the years before, the advanced design was already completed. 12 LK-1's were to be built in 1965 to 1966 with first flight in 1967.
The capsule had the same shape as the US Apollo capsule, but was much smaller (2.8 m diameter vs. 3.9 m for Apollo). The 17 tonne LK-1 would be into a parking orbit of the earth by the UR-500K launch vehicle. The rocket engine of the LK-1 itself would put it on a translunar trajectory and perform necessary midcourse corrections.
Then on October 13, 1964, only two months after the project, Khrushchev was removed from power and Brezhnev's faction assumed control of Politburo. This immediately led to a shift of political forces. Chelomei lost his main patron and Korolev immediately again attempted to gain control of the manned circumlunar project. Many of Chelomei's pet projects, such as the Raketoplan, the Kosmoplan, and the UR-200 booster, were cancelled. But following review by an expert commission headed by Keldysh, the LK-1 and UR-500K were permitted to continue.
|N1 Rollout - N1 Rollout - view from inside MIK|
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While he had not been able to obtain approval to begin development of his Soyuz A circumlunar spacecraft, work on the Soyuz 7K-OK earth orbital spacecraft was authorised in a decree of 3 December 1963. Korolev continued work on the 7K-OK while covertly developing a 7K-L1 circumlunar version. By mid-summer 1965 Korolev noted that while development of the Soyuz was proceeding on schedule, Chelomei's LK-1 was badly lagging behind (although the Proton booster was on schedule). On 25 August 1965 a knock-down-drag-out meeting was held between Ustinov and the Chief Designers. Although he was received as much criticism as he gave, Korolev's hand can be seen in supporting the elimination of duplicate projects (such as Chelomei's LK-1). Ustinov compared the mounting successes of the American space projects with the continuing delays and failures of the Soviet projects. The problems were clearly gross underfunding of the entire programme and duplication of effort between the Chief Designers. The Chief Designers fought bitterly but would not back down. But it was finally clear to the leadership that some drastic reorganisation was required to keep up in the space race. Korolev could see that he would soon have the whole thing under his control.
On 25 October 1965, Korolev regained the project for manned circumlunar flight. Chelomei's LK-1 spacecraft was cancelled. In its place, Korolev proposed to use a combination of Chelomei's UR-500K booster, Korolev's Block D stage being developed for the N1-L3, and the Soyuz 7K-L1.
The resulting L1 was officially developed according to the decrees of 3 August 1964 and 25 October 1965. It consisted of the 11S824 Block D rocket stage, the 11F91 7K-L1 spacecraft, and the Block L-1 SAS (launch escape system). The UR-500K rocket would boost the L1 to suborbital velocity. Then the L1, with a total mass of 27.5 tonnes, would ignite its Block D stage. The Block D burned for 160 seconds the first time, placing the complex into an earth parking orbit. At translunar injection, total mass was 18.2 tonnes. After burnout of the Block D, it would separate and the 5.7 tonne 7K-L1 would accomplish necessary midcourse trajectory corrections using its own engine.
The Block D was derived from the N1-L3 moon landing braking stage. The spherical liquid oxygen oxidiser tank was of titanium and was enclosed by thermal insulation blankets. The toroidal kerosene fuel tank was also of titanium. The 11D58 engine had a thrust of 8.5 tonnes and a specific impulse of 349 seconds. It was derived from the 8D726 rocket engine of the 8K713 GR-1 Global Rocket, which itself was derive from the S1.5400 Block L of the 8K78 Molniya launch vehicle.
The 7K-L1 was a modified Soyuz 7K-OK. The forward living module was deleted. Special on-board systems were added for interplanetary navigation. The SAS launch escape system could pull the spacecraft away from the failing booster up to the point of second stage ignition. It is interesting to note that the reserve parachute was deleted in order to add an exit hatch in the side of the re-entry capsule. Originally Korolev considered that the 7K-L1, for either safety or mass reasons, could not be boosted directly by the UR-500K toward the moon. Therefore he envisioned launch of the unmanned 7K-L1 into low earth orbit, followed by launch and docking of a three man 7K-OK with the L1. Two cosmonauts would then transfer to the L1 through the side hatch. The 7K-OK, with one cosmonaut remaining, would separate and return to earth. The two cosmonauts in the 7K-L1 would then be boosted toward the moon. Development of the L1 began in November 1965.
While a victory for Korolev, it was an added project at a time that the N1-L3 was in serious technical and schedule problems. Korolev had begun to admit to his colleagues that the moon landing could not come until 1969 at the earliest.
On January 14, 1966, only three months after taking control of the L1 project, Korolev died in Moscow during colon surgery. He had kept his illness a secret from his colleagues and his death at 56 came as a surprise to many. There were delays in appointing a successor. After Kozlov in Samara turned down the job it finally went to Korolev's deputy, Mishin. But during the course of 1966, building on the work already done on the 7K-OK, drawing release and fabrication of the 7K-L1 spacecraft went ahead with astonishing speed. In February 1967 the government approved an integrated L1/L3 project plans indicating a first manned L1 circumlunar mission as early as June 1967.
The L1 would fly, but it would not succeed in putting a Soviet citizen around the moon. To briefly summarise the flights of the L1 project:
Continued in Part 2.