DLB Module Deployed Media Gallery

The N1 draft project of 1962 spoke of 'establishment of a lunar base and regular traffic between the earth and the moon'. Korolev raised the matter informally at tea with Chief Designer of rocket complexes Vladimir Pavlovich Barmin, head of GSKB SpetsMash (State Union Design Bureau of Special Machine-Building). Barmin was interested in pursuing the subject, but how could such a base be placed on the moon. 'You just design the base', Korolev assured him, 'and I'll figure out how to get it there'. The project ran 12 years and was known to SpetsMash as the 'Long-term Lunar Base' (DLB) and referred to jokingly by detractors as 'Barminograd'. It would have put a semi-permanent nine-man base on the moon by 1975.

Consideration was given to using the same elements in expeditions to other planets. Under the DLB studies SpetsMash defined purposes of the base, the principles of its construction, phases of its deployment and composition of its scientific and support equipment. The enthusiasts that worked on the project were naturally known as 'lunatics'.

The DLB would have utilized unmanned Ye-8 spacecraft designed by the Lavochkin OKB to conduct initial reconnaissance of the prospective moon base site. These would use lunar soil core drills to obtain samples of the soil and return them to earth for analysis, and Lunokhod rovers to survey the site. If the site was found to be satisfactory, these craft had radio beacons which would guide follow-on elements of the base to precision landings.

Ambitious articulated mobile nuclear-powered Lunokhod laboratories would take the cosmonauts from the landing sites on long-duration traverses of the lunar surface. The Lunokhods were equipped with core samplers and manipulators so that the crew could conduct collection of surface samples from within the pressurized cab without the need to always exit the ship and conduct surface operations in space suits. One of the main objectives of the base would be the location and mining of Helium-3 for use in nuclear fusion reactors on earth. Rare on the earth, Helium-3 was abundant on the moon, having collected in the regolith from the solar wind.

Barmin's lunar base would be crewed by nine cosmonauts and consist of nine modules. These modules would have a length of 4.5 m during launch and transport on the moon. Once position in place on the surface of the moon and inflated with air, they would telescope out to 8.6 m length with a total floor area of 22.2 square meters. Power would be provided by nuclear reactors.

The nine modules would be pre-equipped in the factory for specialized functions: command module, laboratory/warehouse module, workshop module, midpoint module, medical/gymnasium module, galley module with dining room, and three living modules. A prototype of one of these modules was used in 1967 for a one-year closed-cycle living experiment at the IBMP (Institute for Bio-Medical Problems). Based on the results of this experiment it was planned that the units on the moon would have a false window, showing scenes of the Earth countryside that would change to correspond with the season back in Moscow. The exercise bicycle was equipped with a synchronized film projector, that allowed the cosmonaut to take a 'ride' out of Moscow with return. These psychological measures were felt important to maintain the crew's mental health.

From 1969 the Ministry of Defense backed the project with more serious funding, in a view to leapfrogging the Americans by establishing a Soviet moon base after their Apollo project had been completed. In these later versions, the manned elements apparently used the improved L3 complex (designed for the follow-on two-man lunar landings) to ferry manned crews from earth orbit to lunar orbit and then from lunar orbit to the surface and back. The Block Sr LOX/LH2 stage would be used to insert the components of the DLB into low lunar orbit.

By 1971 the lunar city project was practically complete and Chief Designer Barmin arranged a meeting with Secretary Ustinov, head of all military and space rocketry. He brought along two of this 'lunatics', Aleksandr Yegorov and Vladimir Yeliseyev. The project was defended in a marathon meeting - nine presentations over six hours. At the conclusion, Ustinov agreed that the project should go ahead - but he couldn't decide, at the pace of a walk or the speed of a freight train. In the event, the point was moot. The N1 never successfully flew, and the rocket, and its associated projects, were cancelled in May 1974. In any case, the Soviet economy very likely could never have sustained the cost of the project - 80 billion dollars in 1997 prices.

The 9-man base was considered only a first stage. Elaborate models were built of larger-scale cities on the moon. Payload that needed to be delivered to the lunar surface for initial operations was 52 metric tons. Supply requirements to support operations and continued expansion of the DLB would start at 80 metric tons per year of payload delivered to the surface in 1975, increasing to 150 metric tons per year after 1980. Barmin's base modules were designed to fit within the 5.5 metric ton net surface payload of a single launch of Korolev's original N1 booster. This could later be increased to 6.5 metric tons using the 30-engine N1, then 9 metric tons using the N1M, or 15 metric tons if Chelomei's alternative UR-700 booster was developed.

Unmanned elements of the DLB designed by the Lavochkin bureau and using lunar core sampling drills designed by Barmin flew in 1969-1976 under the 'Luna' program. Although these flights were conducted in direct reconnaissance support of a manned lunar landing and lunar base, at the time it was declared that no Soviet manned lunar landing program existed, and that these unmanned flights represented a way to achieve the results of the American Apollo program without such expense and risk to life. After a number of launch vehicle failures this series of probes had some success. Luna 15 had crashed while attempting to land on the moon while the Apollo 11 astronauts were on the surface. But on September 20, 1970 Luna 16 safely soft landed on the moon and then returned lunar soil to Soviet territory. Lunokhod 1 traveled about a small portion of the Sea of Rains and returned photographs. Luna 19 mapped the gravity field of the moon in preparation of later manned flights. Luna 20 returned to earth more lunar soil, and Lunokhod 2 roved around an area representing the transition zone between the lunar maria and the highlands.

Crew Size: 9. Design Life: One year. Mass: 52,000 kg (114,000 lb). Electrical System: Nuclear reactor. Associated Launch Vehicle: N1.

• DLB Module.  Code Name: Zvezda. Class: Manned. Type: Lunar Habitat. Destination: Moon. Nation: Russia. Manufacturer: Barmin.

  Basic module developed by Barmin's OKB from 1962 for the Zvezda Lunar Base. Cancelled, together with the N1 booster, in 1974.

  Barmin's lunar base would be crewed by nine cosmonauts and consist of nine modules. These modules would have a length of 4.5 m during launch and transport on the moon. Once position in place on the surface of the moon and inflated with air, they would telescope out to 8.6 m length with a total floor area of 22.2 square meters. Power would be provided by nuclear reactors.

  The nine modules would be pre-equipped in the factory for specialized functions: command module, laboratory/warehouse module, workshop module, midpoint module, medical/gymnasium module, galley module with dining room, and three living modules. A prototype of one of these modules was used in 1967 for a one-year closed-cycle living experiment at the IBMP (Institute for Bio-Medical Problems). Based on the results of this experiment it was planned that the units on the moon would have a false window, showing scenes of the Earth countryside that would change to correspond with the season back in Moscow. The exercise bicycle was equipped with a synchronized film projector, that allowed the cosmonaut to take a 'ride' out of Moscow with return. These psychological measures were felt important to maintain the crew's mental health.

  Crew Size: 9. Design Life: One year. Length: 8.60 m (28.20 ft). Maximum Diameter: 3.30 m (10.80 ft). Span: 3.30 m (10.80 ft). Mass: 18,000 kg (39,000 lb). Electrical System: Nuclear reactor. Associated Launch Vehicle: N1.

• DLB Beacon Lander.  Class: Manned. Type: Lunar Logistics. Destination: Moon. Nation: Russia. Manufacturer: Lavochkin.

  In most Soviet manned lunar landing scenarios, versions of the Ye-8 unmanned landers would precede manned landings on the moon. After surveying the planned site, they would remain on the surface and provide a radio beacon that would allow the following LK or LKM manned landers to make a precision landing.

  Associated Launch Vehicle: Proton 8K82K / 11S824.

• DLB Lunokhod 1.  Class: Manned. Type: Lunar Rover. Destination: Moon. Nation: Russia. Manufacturer: Barmin.

  One of several conceptual models of Lunokhod or Marsokhod pressurized surface rovers planned for Soviet moon or Mars expeditions.

  Associated Launch Vehicle: N1.

• DLB Lunokhod 2.  Class: Manned. Type: Lunar Rover. Destination: Moon. Nation: Russia. Manufacturer: Korolev.

  One of several conceptual models of Lunokhod or Marsokhod pressurized surface rovers planned for Soviet moon or Mars expeditions.

  Associated Launch Vehicle: N1.

• DLB Lunokhod 3.  Manufacturer's Designation: Energia. Class: Manned. Type: Lunar rover. Destination: Moon. Nation: Russia. Manufacturer: Barmin.

  One of several conceptual models of Lunokhod or Marsokhod pressurized surface rovers planned for Soviet moon or Mars expeditions.

  Associated Launch Vehicle: N1.

• L5-1967.  Class: Manned. Type: Lunar Lander. Destination: Moon. Nation: Russia. Manufacturer: Korolev.

  At a Lunar Soviet meeting in October 1967 preliminary agreement was reached to study a follow-on to the first N1-L3 lunar landings. A new N1 model was to be developed to launch a new 'L5' spacecraft. This was mentioned as being able to handle 4 to 5 crew, 1.5 to 2.0 metric tons of scientific equipment, and spend three months on the lunar surface. This was to be ready two to three years after the first landing.

  No other details were available, but this was clearly the ancestor of the two-crew L3M and various N1-launced lunar long-duration stay spacecraft planned for the late 1970's. The booster described in the discussions corresponded to the N-IFV-III design in Korolev's 1965 study of future N1 variants. This would have had a payload to low earth orbit of 125 metric tons, implying an L5 mass landed on the moon of about 27 metric tons in a two-launch scenario.

  Crew Size: 5. Design Life: 90 days. Mass: 27,000 kg (59,000 lb). Payload: 1,500 kg (3,300 lb). Associated Launch Vehicle: N-IFV-III.

• Soyuz 7K-LOK.  Other Designations: LOK, T1K. Article Number: 11F93. Manufacturer's Designation: 7K-LOK. Class: Manned. Type: Lunar Orbiter. Destination: Moon. Nation: Russia. Manufacturer: Korolev.

  The two-crew LOK lunar orbiting spacecraft was the largest derivative of Soyuz developed. Given its importance to the Soviet moon landing program, it remains one of the least known manned spacecraft ever to reach flight status. Never reaching space in its all-up form, the LOK was the counterpart to the American CSM (Command-Service Module).

  The LOK was radically different from other spacecraft in the Soyuz series in many respects. The BO orbital module differed from the basic Soyuz in having the Kontakt lightweight docking system, a forward reaction control system module, and a cupola allowing the cosmonaut to make a manual visual docking with the LK lunar lander. The descent module was true to the basic Soyuz form, but significantly heavier than either the 7K-OK earth orbit or 7K-L1 circumlunar versions of the module. The PO/AO service module was radically different from others in the Soyuz series. It featured the Block I propulsion system with a much more powerful engine and greater fuel capacity (required for the maneuver out of lunar orbit). Power was provided by Lox/LH2 fuel cells, a first for a Soviet spacecraft.

  Development History - from L-4 to LOK

  The first outline specification for a manned lunar orbiter came in a Korolev letter to the Central Committee of the Communist Part in January 1960. The Chief Designer proposed an aggressive program for Communist conquest of space. This would be accomplished by development of a new N1 rocket of 1,000 to 2,000 metric tons gross lift-off mass with a 60 to 80 metric ton 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 metric tons in lunar orbit with 2 to 3 metric tons return payload. This lunar orbiter would be twice as large as the L1 'loop around the moon' spacecraft. Following negotiations with other Chief Designers and the government, the final decree 715-296 of 23 June 1960 authorized draft project work on the L1 and the N1 booster but did not mention any N1-launched lunar orbiter.

  Following three years of design and research, a series of potential lunar spacecraft designs were described in a 23 September 1963 letter setting out Korolev's space exploration plan for 1965 to 1975. One of these, 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 metric tons, would be placed into orbit in a single N1 launch, and would consist of:

  • The trans-lunar injection stage, total mass 58 metric tons. If development of a fourth stage for the N1 was not authorized, this could be replaced by three sequentially-fired Soyuz B 9KM rocket blocks developed for the L-1 and L-2 projects.
  • The lunar orbit maneuvering stage, which would have a total mass of 11.5 metric tons. This would break the Soyuz manned spacecraft into lunar orbit and returned it on its transearth trajectory. Five metric tons of propellant would be used for lunar orbit insertion.
  • The L-4 spacecraft, which would be a modification of the 7K Soyuz. This would have a mass of 5.5 metric tons after being placed on a transearth trajectory with a descent capsule mass of 2.5 metric tons.

  At the time of this proposal Korolev favored an earth-orbit rendezvous method to reach the moon. This would require several N1 launches to assemble a 200 metric ton spacecraft in low earth orbit. This would be launched directly to the lunar surface.

  In August 1964 the Soviet Union finally decided to attempt to land a man on the moon before the United States. Korolev took the decision to use the American lunar orbit rendezvous method to reduce the number of N1 launches from three to one. The design work already accomplished on the L4 came in handy to provide a counterpart to the American Apollo CSM. Unlike the CSM, the Soviet LK lunar lander and LOK lunar orbiter would be braked into lunar orbit by a separate stage, the Block D. Therefore the propulsion system of the LOK would be needed only for the critical maneuver of propelling the spacecraft on the return trip for lunar orbit toward the earth. The LOK would have a smaller Block I propulsion stage than that planned for the L4:

  Spacecraft	L-4	LOK
  Main Propulsion Stage	11,500 kg	5,646 kg
  Jettisonable Equipment Modules	3,000 kg	1,400 kg
  Re-entry Capsule	2,500 kg	2,804 kg

  In the original 1964 N1-L3 lunar mission scenario, the LOK, the LK lunar lander, and the Block D deceleration stage would be inserted into lunar orbit by a burn of the Block D. Trim maneuvers would bring the assembly into a 20 km x 100 km orbit by orbit 14. One crewman would spacewalk from the LOK to the LK. After separation from the LOK, the Block D stage, still attached to the LK, would act as a 'lunar crasher' stage, decelerating the LK to 100 m/s four kilometers above the surface. The LK itself would accomplish the final lunar descent. After surface exploration, the single cosmonaut would return to the LK, which would propel itself back into lunar orbit for docking with the waiting LOK and transfer of the crewman and surface samples. The single cosmonaut aboard the LOK would perform the automatic rendezvous and docking with the LK. After the cosmonaut from the LK transferred himself and the lunar samples to the LOK, the LK would be cast off on orbit 38 by jettisoning the forward modules of the LOK. One orbit later the LOK would make the engine burn to take the crew back to earth. If necessary due to weight growth, the BO living module could also be jettisoned prior to this maneuver. The LOK would spend a total of 77 hours in lunar orbit and 82 hours on the homeward coast.

  Technical description of the LOK

  The design mission of the LOK was house the mission crew and provide a means of escape during the trip to lunar orbit, to rendezvous and dock with the LK after its return from the lunar surface, and then return the cosmonauts and their lunar samples to earth. On precursor manned and unmanned missions the LOK would be equipped with photographic equipment to survey potential lunar landing sites. The LOK had an overall length of 10.0 m, a diameter of 2.2 m, and a total mass of 9,850 kg. It was designed to support two cosmonauts on lunar orbital missions of up to 13 days duration.

  The LOK consisted of the following modules, from fore to aft:

  • SU (Stikovochniy Uzel) - Docking apparatus. This was a truncated cone, 455 mm long, topped by three probes that would snare the hexagonal grid atop the LK. A mechanical turn-screw brought the probes out into a splayed position to lock the two spacecraft together. This lightweight device allowed firm connection of the spacecraft without the requirement for a precision aligned docking. It formed part of the Kontakt docking system designed by Mnatsakian at the NII for Precision Instruments.

  • DOK (Dvigateliy Orbitalniy Kompleks) - Orbital engine system. This provided orientation for the LOK during trans-lunar coast and lunar orbit operations. This module, a 790 mm long truncated cone pierced by spherical propellant tanks, was developed by KB Arsenal, Leningrad. Work was concurrent with their productionization of similar maneuvering engine systems for the IS and US maneuverable anti-satellite and anti-ship systems. The module had a total mass of 800 kg, including 300 kg of propellant in six spherical tanks. These were fed by four smaller pressurization tanks to four clusters of thrusters with a total of 24 engines. Two of the clusters consisted of a pair of larger forward-firing translation nozzles, a pair of larger aft-firing translation nozzles canted at about 40 degrees from the vertical, and a single pair of smaller perpendicularly-firing yaw engines. The other two clusters consisted of a pair of smaller perpendicularly-firing pitch engines and two pairs of even smaller tangentially-firing roll engines. The propellant would provide about 90,000 kgf-sec of orientation impulse, which was consistent with the 360,000 kgf-sec provided by the RCS system of the much larger Apollo spacecraft.

  • BO (Bitovoy Otsek) - Living compartment. This was similar to the basic Soyuz, with several important changes. Not a simple sphere or sphere-and-cylinder, it consisted of a forward hemisphere 885 mm long with a radius of 1085 mm, a 236 mm transition, and an 1114 mm long aft hemisphere of 1143 mm radius. In the forward hemisphere a cupola was installed, allowing the cosmonaut a direct forward view in order to make a manual visual docking with the LK lunar lander. It was equipped with the highly classified laser-optical system designed by NPO Geofizika for the Kontakt docking system. As in other Soyuz spacecraft, the BO served as a living area, experimental laboratory, and airlock for EVA operations. A hatch at the base of the module sealed the cabin off from the SA descent module, while a hatch in the lower hemisphere allowed the cosmonauts to exit into space.

    In coming up into the BO from the SA, the cosmonaut first went through a short tunnel leading to the 'floor' of the BO. A cosmonaut floating above the tunnel and facing the hatch would find:

    • To his front, the hatch leading to free space in the lower part of the compartment.
    • To his left, the main console of the compartment, a vertical wall filling about 40% of the cabin. The lower areas were devoid of instrumentation but housed the environmental control system, pressurization / depressurization system, and storage lockers for food, water, and the Orlan space suit for the crew member to remain aboard the LOK. In the upper panel were instruments for monitoring the LOK during cabin operations and when it was depressurized. This included a blue console with strip pressure indicators, a clock and timer, standard Soviet sequencer controls to command and track automated sequences for spacecraft operations, and communications controls. A dark green console provided master toggle switches to activate or deactivate LOK systems. At the top of the console a lattice structure protected plumbing and provided additional stowage.
    • Behind the cosmonaut, were an array of specialized portholes to which were mounted the optics, cameras, and film cartridges of the systems used to map the lunar surface and prospective landing sites. These included a large aperture main vertical camera in the lower wall, a smaller camera to the same alignment above and to the left of that, and an offset camera above the main camera. This equipment would be changed according to the mission - automated lunar orbiter, manned lunar orbiter reconnaissance, or manned lunar orbiter in support of an LK landing mission.
    • To the right of the cosmonaut, an additional photographic porthole in the lower wall. Above that, offset about 30 degrees to the right of the hatch, the control panel, hand controllers, and turret for conducting docking operations.

    In preparation for the departure of the LK cosmonaut for the lunar surface, both crewmen would be present in the depressurized BO. The LK cosmonaut would be wearing a Krechet-94 space suit, and the LOK pilot the lighter Orlan suit. After exiting the BO the LK cosmonaut would move to a large telescoping boom mounted on the exterior of the module. This would take him back to the hatch in the outside of the LK shroud.

  • SA (Spuskaeniy Apparat) - Descent module. In common with the L1 circumlunar version of Soyuz this version of the SA had a thicker heat shield, and seems to have had two hatches - the standard hatch at the apex, leading to the BO, and a side hatch allowing direct access to space. In the case of the L1, the presence of this lateral hatch meant the reserve parachute had been deleted. The two crew were seated in standard Soyuz seats to either side of a large central structure that housed additional life support equipment, the Krechet lunar surface suit, and lunar samples on the voyage home. The mass of the module was given as 2850 kg at launch, but another drawing shows a mass of 3050 kg at re-entry (perhaps including the lunar samples and the cosmonauts). Based on a control panel exhibited at MAKS 99, the LOK had controls somewhat different from those in the contemporary 7K-OK or L1 versions of the Soyuz. The sequencer panel had the 'on' and 'off' selector buttons to either side of the sequencer windows numbered, as on other versions, but the columns had functional headings, unlike the letters normally used. The SA was 2007 mm long and had a diameter of 2200 mm. Interestingly, a 'theoretical model' of the LOK SA at MAI showed a cylindrical section above the heat shield, as opposed to the conical section of the standard Soyuz. This was not seen on other models or drawings of the LOK.

  • PO (Perekhodnoy Otsek) - Transition compartment. This was a truncated cone connecting the SA to the aft of the spacecraft. It was depressurized and housed four pairs of larger translation engines canted slightly forward so that they went through the spacecraft's centre of gravity. They allowed up/down/right/left maneuvers in three dimensions during docking operations. Propellant was provided from the Block I propellant system.

  • PO (Priborniy Otsek) - Equipment compartment. This was a pressurized cylinder with forward and aft hemi-ellipsoidal pressure bulkheads, similar to that used in other Soyuz models. It contained avionics - communications, telemetry, and command-link units. Most important of these was the digital computer of Pilyugin's guidance system by developed by NIIAP. This guided not only the LOK, but also the entire L3 stack throughout all flight phases from translunar injection from earth orbit through to return to earth. The guidance system was provided position and orientation data from a full-time inertial navigation unit, also by Pilyugin.

  • AO (Agregatniy Otske) - Engine compartment. On the LOK, this was a cylinder fitting and carrying loads over the outside of the spherical propellant tank of the Block I trans-earth injection propulsion system. It was covered on the outside with 24 extremely fragile hinged thermoregulation panels.

  • Block I - This integrated propellant tank/engine assembly was developed by Isayev. It contained 3,152 kg of N2O4/UDMH propellants contained in a spherical 1.9 m diameter tank with a common bulkhead between the oxidizer and fuel. This tank fed two primary engine assemblies:
    • The two-nozzle S5.51 engine had a total thrust of 3,388 kgf, a specific impulse of 314 seconds, and was used for the 1100 m/s trans-earth injection maneuver at the end of lunar orbit operations.
    • The S5.51 was flanked by the two smaller nozzles of the S5.53 engine. With a total thrust of 417 kgf and a specific impulse of 296 seconds, this was used for lunar orbit maneuvers and mid-course corrections on the way back to earth. It was rated for 35 firings. The same engine was used in the lunar flyby spacecraft (Soyuz L1, L1E, L1P, and L1S) and was a close relative of the two-nozzle back-up engine used on the Soyuz 7K-OK orbiter.

    The Block I propellants were also fed to very 16 small thrusters for roll, pitch, and yaw mounted on the base of the EO. These were used for orientation on the flight back to earth.

  • EO (Energo-Otsek) - Power Module. This compartment was the flared base of the LOK. It connected the LOK to the payload shroud surrounding the LK and Block D stages during the trip to the moon until the LK/Block D separated from the LOK. The centre of the space was taken up with the shrouded engine assembly of the Block I. Arranged within the periphery of the truncated cone were four fuel cells, their associated liquid oxygen and hydrogen tanks, and a refrigerator unit to keep the cryogenic liquids in liquid state. The outside of the EO was covered by tubular radiators of the refrigeration unit.

    The use of a fuel cell was unique in the history of the Soviet space program and did not emerge again until the Buran shuttle orbiter of twenty years later. The Volna-20 fuel cells were developed by the Ural Electrochemical Enterprise. Each cells had a mass of 70 kg and could provide 1.5 kW of power at 27 V for 500 hours. The cells were fed by 600 kg of liquid hydrogen and oxygen. The water generated by the reaction of the hydrogen and oxygen was used by the crew.

  Development and Flight History

  Korolev had come up with using the lunar orbit rendezvous method for a lunar landing in response to the Soviet leadership demanding that he beat the Americans to the moon. Unfortunately, the leadership made this decision three years after the beginning of the Apollo project, and at the same time would not budget for more than four N1 launches a year. The only conceivable way of beating the Americans was to use a single N1 launch. But the N1 was designed to launch only 75 metric tons into low earth orbit, and OKB-1 calculations showed a minimum of 100 metric tons would be required for an LOR mission using Lox/Kerosene propellants in the booster.

  Korolev was able to convince himself that by using a combination of modifications to the N1, chilled propellants, and modified trajectories he might be able to squeeze a 95 metric ton payload out of the booster. This then had to be the total mass of the L3 assembly, including the trans-earth injection stage. This was the plan sold to the leadership, but as soon as development started it was apparent that a 95 metric ton L3 would be unachievable.

  The motivations for continuing were many. Mishin, Deputy Designer at OKB-1, wanted to go ahead with development of the N1 whether it could send a man to the moon or not. He believed it was critical to a range of future Soviet space projects and he was not about to kill it by telling the leadership it could not accomplish its only assigned mission. Bushuev noted the only way to get the necessary performance would be to use Lox/LH2 propellants in the second and third stages, as the Americans had done with the Saturn V. But this was not authorized in the approved draft project. Korolev was not about to tell the leadership that he had mis-estimated in their original proposal, or that Russian engines were not as good as American engines.

  Two days after the N1-L3 one-shot scheme had been approved, a council of Chief Designers met to consider how to accomplish it. The use of Lox/LH2 stages was proposed to boost payload, but rejected due to the lack of Soviet experience with the propellants. The use of higher-performance N2O4/UDMH engines from Glushko was proposed, but again rejected by OKB-1. The designers became prisoners of their positions. There was no choice but to proceed with 95 metric ton L3 as proposed. But this meant that the spacecraft estimated masses had no reserves. The LK mass was absurdly optimistic. During development the engineers would fight over grams of mass for subsystems.

  The weight restrictions had consequences. By 20 December 1965 difficulties and arguments over development of the guidance system had reached a head. Pilyugin, the guidance subcontractor, wanted to use the latest technology in order to meet the weight and power consumption goals, including a digital computer and a gyroplatform of his own design. This was contrary to the decree, which required him to use a gyro platform from the customary supplier of OKB-1, Kuznetsov at NII-944. Pilyugin was reporting that he wouldn't have a guidance system ready for the N1 booster until late1968, let alone systems for the LOK and LK. Therefore an expert commission was convened by Keldysh, Head of the Soviet Academy of Sciences.

  Korolev kicked off the meeting by complaining that if he had another 800 kg in payload mass, existing systems could be used. Pilyugin and Ryazanskiy provided an overview of their guidance systems, showing the concepts and the mass problems. The first launches could be made with the analogue systems desired by OKB-1, but the digital system would be required to conserve fuel cell consumables and accomplish a lunar landing mission. A discussion of fuel cell contractors led to a suggestion to use radio-isotope thermal generators (RTG's) from the KB Atomic Machinery Factory in the Urals. They had worked with Korolev for years on development of nuclear electric propulsion. But it was decided that there was no technical basis for proving reliable operation of RTG's in a vacuum. In addition, the fuel cells produced water for the crew, which would have to be carried separately if RTG's were used.

  A month later Korolev was dead, and OKB-1 was without a Chief Designer. The leadership argued over the subject all during 1966. In the meantime, the American Apollo program was progressing rapidly, while the L3 project languished. It had become clear that a Soviet lunar landing could not be accomplished earlier than 1970, while the Americans were hoping for a landing in 1968 if all went well. By October 1966 the launch plan had slipped to the following:

  • N1 2L, 3L, and 4L would take L1S unmanned spacecraft on lunar flybys with recovery of the capsule on earth in 1968-1969
  • N1 5L and 6L would launch piloted LOK's with automated LK landings on the lunar surface in 1969-1970
  • N1 8L, 9L, and 10L would carry manned Soviet lunar landing missions no earlier than 1970

  It was also becoming apparent that the weight optimists were fighting a losing battle and that the N1 simply could not accomplish the one-launch scenario. This led to an examination of alternate launch plans. Meanwhile, amid a great deal of finger-pointing in the leadership, the decision was finally taken to appoint Mishin head of what was now dubbed TsKBEM in December 1966. The program lurched forward with the actual scenario for a lunar landing in constant flux.

  Hardware development experienced continued delays. By the end of 1966 the Block I propulsion system was scheduled for its first ground tests in July 1967. New communications systems (Foton and Mezon) required to handle multiple manned spacecraft were not to be installed at ground stations until the end of the year.

  Bushuev came up with plan in 1967 that provided for added safety through the use of two Proton and two N1 launches to get a single man safely to the lunar surface and back. Under this scenario, two Proton rockets would launch automated Ye-8LS lunar rovers to the surface. These would scout the local terrain. The rover would park at the selected site and serve as a beacon for the LK landers that would follow. An N1 would be launched with an unmanned LOK and the backup 'reserve' unmanned LK (LKr). The LKr would land with minimum propellant consumption, homing in on the Ye-8LS beacon. The LOK would photograph the site from lunar orbit and then return the film to earth. One month later, the manned expedition would be launched. A single cosmonaut would ride a second LK to the lunar surface, again using the homing beacon. If there were any problems, the cosmonaut could walk or drive one of the rovers to the LKr and have a second chance to get back to the LOK in lunar orbit. The Ye-8LS were equipped with a driver control panel and supplies of oxygen and water for the Krechet suit. They rover reach 1.2 km/hour for a slow-motion ride to the other lander if necessary.

  Also in 1967 a substantive plan for test of the LOK in earth orbit was developed. The earth-orbit versions of the LOK was dubbed the T1K. By March 1968 it was planned three flights would be made launched by Chelomei's Proton booster in October-November 1968. The last of these would be manned and involve docking with the T2K test version of the LK lunar lander. In August 1968 discussion of using the Yastreb lightweight space suit for these missions was underway, Incredibly, at the same time, fundamental arguments over the rendezvous and docking system continued. Some factions preferred the Igla system which was being proven on the orbital version of Soyuz. Others preferred the Kontakt system. The decision, inexplicable in retrospect, was to continue with the Kontakt system for the L3.

  Following the successful flight of Apollo 8 around the moon in December 1968 the project managers finally realized they had no chance for beating the Americans to a lunar landing. N1's 3L through 6L would not have enough payload for a landing mission. The LOK and LK were not nearly finished and the landing scenarios had been redrafted three times since the project had begun. A council of chief designers considered the options:

  • Continue with the current hardware, using a two-launch N1 scenario. This was supported by Kryukov, Mozzhorin, Pilyugin, and Ryazanskiy.
  • Develop an uprated N1 with a Lox/LH2 upper stage and new spacecraft. The favored configuration would by the N1F-V4. Two would be used to launch a completely new L5 complex, which would allow 4 to 5 cosmonauts to live for up to two months on the lunar surface. This had the potential to leapfrog the Americans rather than merely match their feat. This was pushed by OKB-1 engineers but would involve substantial additional funds.

  A meeting of the Council of Chief Designers on 24 January 1969 made some brutal recommendations to the Soviet leadership. The T1K, T2K, and L1E were cancelled. The LOK and LK, although overweight, would continue in low-priority development. A month later the first launch attempt was made with the N1. N1 3L cleared the pad but an engine control system fault shut down all first stage engines after 68 seconds of flight. It was considered a typical first flight test and the program was not jeopardized.

  On 29 and 30 May 1969 the launch commission for the next launch, N1 5L, was held. Mishin pushed for a decision, if 5L was successful, to launch the first LOK aboard N1 6L by the end of 1969. Mishin expected to have an all-up spacecraft by then, fully equipped with the fuel cells, the digital computer from NIIAP, the Kontakt docking system, and the Geofizika optical docking system. The cryogenic lox and LH2 for the LOK's fuel cells would be pumped aboard the spacecraft once the rocket was on the pad. The safety issues of handling LH2 was a source of continuing concern for the military. There was also a great deal of skepticism of Mishin's ability to produce a complete LOK by year's end.

  Following the spectacular failure of N1 5L on 3 July 1969 the flight schedule was modified again. It now read as follows:

  • In 1970 - launch of N1 6L and 7L with Soyuz 7K-L1S payloads
  • In 1972 - launch of N1 8L, 9L, and 10L with LOK payloads on automated lunar orbit missions. The LOK's for these automated flights would be equipped with photographic equipment for surveying potential landing sites.
  • In 1973 - launch of N1 11L, 12L, and 13L on piloted lunar orbit missions
  • In 1974 - launch of N1 14L, 15L, and 16L to accomplish two lunar landings (evidently the first flight to provide the reserve LK for the next two flights).

  Work continued on the LOK. Arsenal was still having problems in January 1970 with the forward engine system. By February 1970, of 16 LOK's authorized, only three were in ground test for possible future flight operations. Seven were partially assembled, and the remainder existed only as unassembled parts.

  A crash program had been initiated to develop the Salyut 1 space station before the American Skylab. Development of the LOK and LK were given a very low priority. On 14 April 1971, at an expert commission reviewing the N1, Keldysh suddenly changed his long-standing support for the L3 and listed a series of 'mandatory changes' which would completely invalidate the LOK/LK design. Among these were:

  • Use of redundant Kontakt or other systems for docking
  • Inclusion of an internal transfer hatch, as had been developed for the Salyut station. This would eliminate the need for the lunar landing astronaut to spacewalk to the LK
  • Re-integration of the use of Babakin's Ye-8LS surface robots into the mission plans to provide pre-landing site surveys, homing beacons, and backup surface transportation
  • Elimination of the possibility of splashdown in the ocean in the event of guidance failure during capsule re-entry.

  Just to incorporate the docking tunnel would mean a three year delay. However it was decided to ignore the demands for the time being. If the next N1 succeeded, the point could be argued; if it did not succeed, it would be moot.

  It was decided not to risk functional spacecraft in further N1 tests until the booster had proven itself. Therefore 6L and 7L would carry only LOK and LK mass models, with 8L now scheduled to carry an all-up automated LOK and LK spacecraft. During 1971, LOK certification tests began in earnest, including water-landing tests and launch escape system live fire tests. The fuel cells were finally tested in 1971-1972, producing 4.5 kW at 60% efficiency.

  By this time, however, Mishin's team was already concentrating on a completely new spacecraft - the L3M - that would make a direct landing on the lunar surface. This would be joined to new Lox/LH2 propulsion stages in earth orbit using multiple N1F launches - the same scenario originally advocated by Korolev. A state commission under Keldysh studied the alternatives throughout 1971, and the final conclusion was to abandon any use of the original L3 (LOK+LK) lunar orbit rendezvous spacecraft in a manned landing. The assets already built would be used only for unmanned tests of the N1. Any Soviet manned lunar landing would rely on the L3M and multiple N1F launches to support a landing no earlier than 1977. But these plans were never fully funded, and in the absence of any formal go-ahead, Mishin continued to complete qualification and flight test of the LOK.

  Therefore the payload for N1 7L was changed again, to be the first actual test flight of the LOK (article 6A was selected for the honor). A mock-up of the LK would accompany it on a lunar orbital mission. The flight plan for the mission was issued on July 19, 1972. N1 7L was to place the 89,803 kg L3 stack into a 200 x 740 km earth orbit at a 50.7 degree inclination. After 24 hours of on-orbit tests the Block G translunar injection stage would hurl the payload toward the moon. However even with the underweight payload the Block G could not complete its mission in this configuration. The Block D would have to fire for 44 seconds after the Block G had depleted its propellants in order to reach earth escape velocity. In case of a failure to reach a lunar trajectory, the LOK was to separate, conduct operations in earth orbit, and then deorbit for a splashdown in the Indian Ocean.

  After four days transit to the moon, with two mid-course corrections, the Block D would fire to place the assembly into a 175 km circular lunar orbit at 98.5 hours into the flight. The Block D would shape the orbit to a final 40 km x 175 km orbit on maneuvers on the fifth and 27th orbits. The LOK was to conduct photographic sessions of potential future landing sites on orbit 14, 17, 34, and 36. After 3.7 days in lunar orbit, the LOK's forward living compartment would separate and the Block I engine would fire to put the spacecraft on a translunar trajectory. Eight minutes prior to re-entry the descent module would separate, c

  Crew Size: 2. Design Life: 13 days. Orbital Storage: 13 days. Typical orbit: 2384 km x 5269 km at 56 degrees inclination. Length: 10.06 m (33.00 ft). Maximum Diameter: 2.93 m (9.61 ft). Habitable Volume: 9.00 m3. Mass: 9,850 kg (21,710 lb). Main Engine Thrust: 33.224 kN (7,469 lbf). Main Engine Propellants: N2O4/UDMH. Main Engine Propellants: 3,152 kg (6,948 lb). Main Engine Isp: 314 sec. Spacecraft delta v: 1,100 m/s (3,600 ft/sec). Electrical System: Fuel cells. Electric System: 1.50 average kW. Electric System: 250.00 kWh. Associated Launch Vehicle: N1.

• LK.  Other Designations: T2K. Article Number: 11F94. Manufacturer's Designation: LK. Class: Manned. Type: Lunar Lander. Destination: Moon. Nation: Russia. Agency: MOM. Manufacturer: Korolev.

  The LK ('Lunniy korabl' - lunar craft) was the Soviet lunar lander - the Russian counterpart of the American LM Lunar Module. The LK was to have landed a single Soviet citizen on the moon before the Americans, winning the moon race. It completed development and test flown very successfully in earth orbit, but never reached the moon because the N1 booster required to take it to the moon never had a successful flight.

  This was not to be, for reasons covered elsewhere (see Soviet Manned Lunar Projects). Because the translunar payload of the Russian N1 rocket was only 70% that of the American Saturn V, the LK differed in many ways from the LM. It had a different landing profile; it was only 1/3 the weight of the LM; it was limited to a crew of one; it had no docking tunnel (the cosmonaut had to space walk from the LK to the LOK lunar orbiter). Unlike the LM, the LK did not use a separate descent stage to go from lunar orbit to landing on the surface. A braking stage, the Block D, took the LK out of lunar orbit and slowed it to 100 m/s at an altitude of 4 km above the lunar surface. From there the LK used the engines of its Block E stage to soft land on the moon. The Block E also served as the ascent stage to return the LK to lunar orbit.

  The LK consisted of four primary modules:

  • The LPU landing gear, which allowed landing on the lunar surface. The LPU remained behind on the lunar surface, acting as a launch pad for the rest of the LK
  • The Block E rocket stage, which soft landed the LK on the moon and returned it to lunar orbit
  • The Lunar Cabin, the pressurized semi-spherical cabin where the cosmonaut was located
  • The Integrated Orientation System, a pod of small thrusters to orient the spacecraft. Atop the pod was the large hexagonal grid of the Kontakt docking system

  Consider now the LK in depth. This article is organized into the following main sections:

  • The N1-L3 Lunar Mission Profile
  • Development of the LK
  • LK Flight Tests
  • Technical Description of the LK

  The N1-L3 Lunar Mission Profile

  On 3 August 1964, Command number 655-268 issued by Central Committee of Communist Party gave Soviet Chief Designer Korolev the objective of putting one man on the moon and returning him safely to earth - ahead of the Americans.

  Prior to this, Korolev had concentrated on the earth orbit rendezvous method. His September 1963 L3 design was a 200 metric ton direct-lander requiring three launches of his giant N1 rocket and assembled in low earth orbit. This L3 spacecraft would make a precision 'blind' landing, homing in on a beacon aboard an L2 robotic lunar rover which had already been parked at a suitably flat touch-down point. The 138 metric ton trans-lunar injection stage would propel the L3 spacecraft towards the moon. The 40 metric ton lunar braking stage would ignite 200 to 300 km above the surface. After burnout, it would separate above the surface, allowing the 21 metric ton lunar soft landing/ascent stage, with variable-thrust engines to make a soft landing on the surface. The landing leg structure and soft landing engines would be left behind on the moon. The ascent stage would propel the 5 metric ton Soyuz L1 manned spacecraft back to earth. This capable but expensive spacecraft would have accommodated a crew of three for ten days of lunar surface exploration.

  In order to beat the Americans, the redesigned N1-L3 exploited a variant of the Apollo program's lunar-orbit rendezvous method to reach the moon's surface. In this way the mission could be accomplished in just one launch of an improved N1 rocket. The L3 complex designed for the mission, with a total mass of 95 metric tons, would consist of the Block G translunar injection rocket stage; the LOK lunar orbiter; the LK lunar lander; and the Block D deceleration stage.

  The N1-L3 lunar flight plan evolved during the course of the program. By the end of LK development it was as follows:

  • The L3 complex would be injected into a 220 km, 51.8 degree inclination parking orbit of the earth. Up to one day could be spent in earth orbit before trans-lunar injection.

  • The Block G stage was ignited, putting the complex into a translunar trajectory. The Block G then separated.

  • During a 3.5 day translunar coast the Block D stage would perform two mid-course corrections. It then would brake the LOK/LK/Block D stack into an equatorial elliptical lunar orbit. The Block D would be restarted twice to adjust the orbit, first to a circular 110 km orbit, then to bring the pericynthion down to 14 km. The Block D could restarted for up to 4 days in lunar orbit.

  • The LK pilot would spacewalk from the LOK to the LK and check out the lander and Block D systems.

  • The LK/Block D then separated from the LOK. The LK was capable of 72 hours of autonomous operation, 48 hours of which would normally be on the lunar surface. As it approached the landing site, the Block D began its main burn and braked the LK from to 100 m/s at four kilometers above the lunar surface. (Later in development this was reduced to 1.5 to 2.0 km above the surface). The Block D then separated and crashed on the moon about 4 km from the separation point.

  • The landing radar acquired the surface at an altitude of 3000 m. The LK's Block E stage then ignited its engines at full 2,050 kg thrust until vertical velocity reached zero. The engine was then throttled back to 850 kgf hover thrust and maneuvered to a soft landing on the surface. Propellant allowance for the whole maneuver was 280 kg, which allowed about 50 seconds hover time to divert to an alternate landing point up to 100 m away from that originally selected by the automated system. Later in development there was less than a minute total for the landing maneuver, including only 15 to 20 seconds of hover time.

  • Four hours would be sent in surface operations on the first landing. The cosmonaut would exit the LK to the lunar surface. The space suit was limited to 1.5 hours on the surface at a time. The first Soviet space walk was to consist of: planting the flag; deployment of a very limited array of scientific instruments; taking soil samples; photography of the landscape; and cosmonaut commentary on the lunar surface. The LK could spend a total of from six to 48 hours on the lunar surface on later flights.

  • After returning to the LK's Lunar Cabin, the cosmonaut would seal the lunar samples in a hermetic container and then repressurise the cabin. The LK Lunar Cabin and Block E ascent stage would then take-off from the LK landing gear (LPU) and fly back into lunar orbit. The LOK orbiter would rendezvous and dock with the LOK using the 'Kontakt' system. The LK cosmonaut then space-walked from the LK back to the LOK with the lunar samples. The LK was then cast off.

  • After up to one additional day in lunar orbit, the LOK's Block I engine would put the LOK into trans-earth trajectory. 3.5 days was to be spent on the coast back to earth with two midcourse corrections en route. Before re-entry, the descent module separated from the LOK with the two cosmonauts aboard. It re-entered the earth's atmosphere over the South Pole at 11 km/sec, skipped back out to space after slowing down to 7.5 km/s, then soared 5,000 km before making final re-entry and landing on the territory of the USSR.

  Development of the LK

  The N1-L3 project was too big for one enterprise. Korolev's OKB-1 was assigned general management of the project. V M Filin was named manager for the LK within OKB-1. However detailed design, qualification, and construction of the LK Block E engine system was subcontracted to Yangel's OKB-586 in Dnepropetrovsk, Ukraine.

  The advance design project for the N1-L3 was completed on 30 December 1964. The decree for production of 16 shipsets of spacecraft and boosters was issued on 26 January 1965. The N1-L3 was to manufactured to the following schedule: 4 in 1966; 6 in 1967; and 6 in 1968. The plan was for the first launch of the N1 to be in the first quarter of 1966, with the first lunar landings in 1967 to 1968, ahead of the American goal of 1969.

  But as soon as detailed design of the LK began it was realized that the mass of the spacecraft in the draft project was completely unrealistic. The young engineers that had done the preliminary LK design had made numerous absurd assumptions. They had assumed a soft landing delta v of only 30 to 40 m/s (200 to 300 m/s was a more realistic estimate). A thirty degree braking angle was assumed after separation, but at this angle the radio altimeter couldn't detect the surface. Such optimistic assumptions resulted in the draft project putting the mass of the LK at 2 metric tons, with a crew of two. (The final LK would have a mass of 5.5 metric tons and be able to accommodate only one cosmonaut!)

  Still, Yangel wanted to be sure to leave room for a crew of two in the cabin. But it was quickly discovered that this simply could not be done within the 40 to 50 metric ton low earth payload allotment for the LK/Block D. Given the original mis-estimate, throughout the project weight reduction was a constant concern. A separate descent stage would have had greater economy, but this presented numerous other problems not well understood when the project started. The Chief Designers offered prizes of 50 to 60 rubles per kilogram of weight reduction identified by project engineers. 500 kg was saved just by optimizing the rendezvous orbit.

  The capability and accuracy of the landing radar system was the crucial first problem in development. The prompt and precise determination of the velocity and altitude of the LK after separation from the Block D was the key to minimizing propellant usage for the landing and determined the sizing of the whole LK vehicle (due to the propellant reserves required for touchdown and hover maneuvers).

  The landing radar system was designated Planeta. Planeta consisted of four antennae, with their beams arranged in an asymmetric pyramid. Three determined the velocity vector using Doppler, while the fourth beam, in the central position, determined altitude above the surface. The system was simple and reliable. It was later proven on the Luna Ye-8 automated lunar sample return probes.

  Numerous problems had to be solved regarding the reflection of the radar beam from the surface - problems analogous to those tackled a decade later in America in the design of stealth aircraft. Tests of the Planeta system aboard MiG-17 aircraft indicated that the initial radar reflectivity assumptions were wrong by several orders of magnitude.

  Ignition of the Block E stage was commanded automatically by the Planeta system when the LK was 3 km from the touchdown point. After eliminating the vertical velocity, the final landing maneuver was commanded by the cosmonaut. Landing was made in the deep throttle range of the Block E. Engine shutoff was commanded automatically by the Planeta system.

  OKB-1 Chief Designer Mishin allowed only a 280 kg propellant reserve for the entire landing maneuver. This constraint prolonged development of the Planeta system. In 1967 Yangel finally went to the Chief Designer's committee and informed them that he could not meet the requirement for two complete lunar landers until 1971.

  In 1968 the L3 scheme was overhauled. The original scheme had assumed a landing on the lunar equator. This meant that the LOK orbiter would pass over the landing site once per orbit, every hour. For the ascent of the LK to the rendezvous orbit in this case, a simple gyroscopic platform could accomplish the launch, as was used on the V-2 and R-7 missiles.

  At landing sites away from the equator, within two to three orbits the LOK orbital plane would move too far away from the landing site to make such a pre-programmed ascent into the rendezvous orbit. Therefore a new type of guidance system was required. There were three possible choices:

  • Install a full-capability inertial navigation unit. This would allow the LK to perform a complex dog-leg maneuver during ascent to reach the plane of the LOK orbit (this was the American LM solution)
  • Use a strap-down gyroscopic platform to steer the LK in a pre-programmed deviation from its vertical axis until the LOK orbital plane position was reached.
  • Use the existing platform but develop a pre-set program of yaw angles, set before launch.

  The second alternative was chosen. The LK would use the gyro platform to begin a bank maneuver at 25 to 30 km altitude. The program calculated the angle of tangency and the function of the cut-off of the LK engine. Soviet computer technology was not good enough at that time to equip the LK with an on-board re-programmable digital system. So instead an analogue parametric calculator was developed that took into account all conceivable problems and emergencies and the times at which they could occur. The resulting system was very effective and represented the major avionics system development for the LK.

  A major difficulty during development was getting the cabin centre of mass on the thrust axis. It could not deviate more than 30 mm from the thrust axis or stable flight of the LK would not be possible. This requirement dictated the design of the propellant tanks of the Block E stage and Integrated Orientation System; required the development of special restraints for the cosmonaut in the cabin; and dictated the placement of equipment on the exterior of the LK. In particular the location of the heavy batteries was continually shifted during development.

  LPU Development

  The LPU - lunniy posadocnie ustroistviy - was the landing leg assembly of the LK. It would remain behind on the surface, acting as a launch pad for the Block E rocket stage. .Therefore the LPU not only to had to absorb the shock of landing, but provide a level base for the ascent stage as well. All systems not necessary for ascent were attached to it. A A Sarkisyan was in charge of LPU design.

  The overall LK mass problem meant that there was only sufficient reserve propellant to move no more than 100 m from the original landing point selected by the automated system. Studies of Ranger photographs of the lunar surface indicated that the 100 m requirement meant that it was most likely the LK would land in a crater of 7 m diameter. This translated into the specification that the LPU be able to handle slopes of 30 degrees with the LK centre of gravity being 2.5 m above the surface. The requirement for high confidence unmanned landings also played a role in the stiff requirement.

  The minimum design, as used on the US Surveyor, was three legs. But a three legged craft would require double the span of a four legged design for the same stability, and could not meet the thirty degree slope requirement. The design of the LPU was such an 'interesting' engineering problem that engineers from many sections of OKB-1 and Yangel's bureau proposed solutions. In the end over twenty variants of LPU landing gear layouts were studied, including toroidal rings, within which the LPU equipment would be housed, and some bizarre water-stabilized designs.

  Many of these ingenious approaches were too complex and mechanically risky. Finally V H Shaurov conceived the idea of 'nesting' engines - engines that would fire DOWNWARD at the instant of touchdown to remove all tipping moments from the spacecraft. This 'active' method of touchdown would reduce the complexity of the gear themselves while meeting the 30 degree requirement. In the end two gear schemes - passive (Feoktistov) and active (Shaurov) - were studied using scale models. Volcanic tuff believed to resemble the lunar regolith was imported from Armenia to simulate the lunar surface. A 300 x 400 mm sand pit was modeled with the tuff, including craters. The tests proved the active system, which was used on the LK.

  A full scale mock-up of the final LPU design was built and tested. The shock absorbing techniques developed for the LK gear were later used in the androgynous APAS docking systems developed for Apollo-Soyuz and Mir. Kiselev proposed additional development of an altimeter-triggered soft landing rocket to cancel all vertical velocity, as was done for earth landings of the Soyuz system. But there was no time to develop the system.

  Mounted on the LPU were those systems not required after the landing on the moon: the landing altimeter, parabolic antennae, chemical batteries, and three water tanks for the evaporative cooling system (a fourth was added late in development to trim the centre of gravity).

  Lunar Cabin

  A cabin environment using pure oxygen at 0.40 atmospheres was considered, but the need to develop special armatures, fire-proof materials, and the safety of the cosmonaut resulted in this being rejected. So the cabin environment selected was air at 0.74 atmospheres. This meant the cabin pressure vessel had to be twice as heavy, but this was considered worth it from a crew safety point of view.

  Soviet experience in manual control of spacecraft was limited at the time of LK development. The development team had to return to first principles in determining the control layout and the position of the cosmonaut. The challenging requirements included the need to operate the controls in a pressurized space suit in the event of cabin depressurization. Therefore foot pedals couldn't be used as in a fixed wing aircraft or helicopter. The design team consulted with helicopter and VTOL specialists at aviation design bureaus to solve these problems.

  Development of the correct arrangement and placement of cabin control panels and windows was a long trial-and-error process. It was determined that the optimum viewing angle downwards for landing was 7 degrees. This lower view port was equipped with a collimator for predicting the landing point.

  The Kretchet spacesuit developed, the ancestor of those still used on Mir today, could be entered through a hatch in the back. There was an elaborate system of braces and tie-down strips to fix the cosmonaut in a standing position during spacecraft maneuvers. This was because it was necessary to keep the centre of mass of the cosmonaut on the thrust axis of the engine.

  Ingress/egress development was conducted again by trial-and-error, using full-size LK and suit mock-ups. It was found that the standard hatch developed for the Soyuz orbital module was too narrow for the cosmonaut in the lunar suit. So a special oval hatch had to be developed. This was a controversial solution but was finally approved. The asymmetric mass of the cosmonaut's ladder had to be balanced by placement of equipment on the other side.

  Due to weight considerations, no automatic docking system could be considered, as was used on the Soyuz spacecraft. The system objectives were minimum weight, manual operation, and tolerance to low accuracy docking. Since the cosmonaut would spacewalk from the LOK to the LK and back, no hard dock system, with system connections and a hermetic seal between the spacecraft, was required. The Kontakt system that was developed used a snare-like probe on the active LOK spacecraft. The LK was the passive vehicle, and was equipped with a 1.8 meter diameter, lightweight hexagonal alloy grid. Each of the 108 hexagons was a potential receptacle for the LOK's docking probe.

  The Kontakt system was to have been tested on a series of earth orbit test flights using Soyuz spacecraft. These were postponed as continued N1 launch failures pushed the date of any possible lunar mission further and further back. In April 1969, two separate docking missions were planned for late 1969/early 1970. After Apollo 11's successful lunar landing, the development and launch of the Salyut space station (to beat the American Skylab) took priority. By December 1970, Kontakt missions were scheduled only after Salyut was successfully flown. Kontakt development was finally terminated in October 1971.

  Block E Development

  Originally development of the Block E landing/ascent stage was considered the pacing item in LK development. Drawings for the Block E were already issued in parallel with the draft project. The original specification of 510 kg empty mass for the stage could not be met. There were constant mass allocation fights between the rocket block design team and the cabin design team.

  The LK variable-thrust, restartable engines represented a huge engineering development task. Unusually, Yangel decided to develop the system within his own OKB rather than entrust it to one of the traditional engine design bureau. New materials and new mechanical solutions were required to obtain a reliable, safe, redundant, durable engine that could be used over a wide variation of payload mass. In charge of Block E engine development was Ivan Ivanovich Ivanov, known to all as I-Cubed.

  A key problem in design of both the Block E and the LPU was the flow of gases reflected from the surface during touchdown. In Apollo, the descent stage and its engine were left behind on the lunar surface; therefore it did not matter if the descent engine was damaged on landing (as actually occurred several times). But the LK used the same engine for landing and ascent from the surface. A hydrodynamic design had to be found that would prevent any damage to the engines during the landing maneuver. The final approach was streamlined propellant tanks for the Block E, which allowed the gases to flow up and away from the LPU during landing. The Block E engines were also equipped with clamshell doors, which closed at engine shut-off and prevented damage from foreign particles while the LK was on the lunar surface.

  The propellant tanks were of unusual form. There were not only external gas flow considerations, but their geometry had to be specifically designed to keep the centre of mass within limits during the landing and ascent to orbit. Since the oxidizer was consumed at twice the rate as the fuel, the geometry had to accommodate this fact. Numerous tank layouts were studied before the optimum compromise between geometry and minimum mass was achieved. The self-igniting storable N2O4/UDMH propellants were stored in nested tanks of identical 1.2 cubic meter volumes.

  Integrated Orientation System

  The Integrated Orientation System was mounted above the Lunar Cabin. Yangel had no experience in microthrusters, so development of this system was subcontracted to Isayev. The same N2O4/UDMH propellant combination was used as in the Block E. The forward mounting of the package meant that the installation was 'unclean' - i.e. it introduced not only motion around the centre of gravity of the LK, but translation motions as well. The thrusters were arranged in two independent, redundant systems. In each system 2 x 40 kgf thrusters provided pitch; 2 x 40 kgf yaw; and 4 x 10 kgf for roll. Propellant totaling 100 kg was stored in two tanks. The problem arose how to preserve the centre of mass of the module on the main thrust line of the LK. The solution was to enclose the oxidizer tank within the propellant tank in a double-walled barrel construction.

  The thrusters were pressure-fed using internal diaphragms. This was the first use of such a technique in Soviet spacecraft, and a new steel alloy was developed by Stepanov for the purpose. The tanks were pressurized to 10 atmospheres by helium gas. Operation of the thrusters for continuous periods of up to ten seconds required development of new materials for the nozzles - niobium and graphite. Minimum thrust impulse was as lows as 9 milliseconds. The nozzles were canted 20 degrees from the horizontal when studies revealed that 95 out of 100 times a straight-through design would lose propellant after engine shutoff. This resulted in a mass savings to the LK of 12.5 kg.

  LK Development

  When the final drawings were reviewed, there was a major fight between the Yangel and Korolev bureaus over a 12 kg 'deficit' in the computed total mass out of the five metric ton total. Korolev's bureau used this to put the entire design into question. After frantic study, the difference was traced to calculation involving the inert gas used for propellant tank membrane pressurization.

  Vibration and environmental tests were conducted on equipment at selected stages of fabrication and assembly. Flight tests were conducted of some components.

  Military engineering experts from the Baikonur Cosmodrome had to review the design in order for it to be cleared for use at the launch site. They were experienced in missiles and could not understand the unpressurised operation of some of the equipment in a vacuum, the lack of aerodynamic fairings for cable runs, missing shrouds around the cables, etc.

  Mock-ups and test stands used in LK development included:

  • Egress procedures mock-up. This was the first LK mock-up
  • Electrical test stand ('iron bird') to confirm logic and algorithms for control systems.
  • Electrical mock-up
  • Environmental test mock-up of Block E. This was tested in special vacuum / insolation environmental chambers. It was also used in heat balance studies.
  • Mock-up for antenna tests
  • Three Block E's for firing tests
  • Design of the landing system and cosmonaut training were accomplished on a specially-equipped Mi-4 helicopter, special test stands, and various partial task simulators.

  LK Flight Tests

  The T1K and T2K versions of the LOK and LK, respectively, were designed for independent earth orbital flight tests of the spacecraft. The T1K was to be launched by Proton and the T2K (also designated LK6/T2K ) by the Soyuz launch vehicle. This special 11A511L version of the Soyuz booster was equipped with a strengthened upper stage and bulbous fairing to accommodate the LK. An entire separate development team under Yu M Labutin was required to develop the special systems necessary for unmanned earth orbit test operations. 20 such systems were used on the T2K, including modifications of those developed for the Soyuz spacecraft. The Labutin team also had to decide what systems could logically be tested in earth orbit and which could not.

  Three T2K's were built, in what was envisioned as a three flight program:

  Flight 1 - Follow the standard engine profile Flight 2 - Induce or simulate various abort profiles Flight 3 - Reserve in case of failures on Flights 1 and 2

  The flight programs were carefully constructed to allow time after each maneuver before the next one would be conducted. This allowed careful measurement of the resulting orbit after each maneuver in order to verify telemetered performance data, as well as time for playback of all telemetry, radio, and television of the events. It was difficult to arrange the schedule within the available LK battery amp-hours.

  Inputs that would normally be done by the crew in the landing phase would have to be simulated and commanded from the ground. In order to accommodate the extra diagnostic and telemetry equipment, a second equipment section was installed on the T2K. Unique earth orbit sensors (solar/stellar, ion flow) were installed as well. These were required to orient the LK along the axis of the orbit.

  The T2K crews worked day and night preparing the spacecraft, and finally the first T2K was shipped to Baikonur for launch. Each T2K was tested before flight in a vacuum insolation chamber. During vacuum chamber tests at Baikonur, one of the equipment sections decompressed. It was found to have had ten microscopic holes punched into it during transport. These were repaired. Finally fuelled and cleared for launch, the first T2K was launched on a sunny morning in November 1970. The three tests of the T2K went of without a hitch:

  • 1970-11-24 - Cosmos 379 - T2K s/n 1: In demonstration of lunar landing and ascent maneuvers, first went from 192 km x 233 km orbit to 196 km x 1206 km orbit, with a delta V of 263 m/s representing the hover and landing maneuver after separation from the Block D. It them simulated the ascent maneuver to lunar orbit, going from a 188 km X 1198 km orbit to a 177 km X 14,041 km orbit with a delta V of 1,518 m/s.

  • 1971-02-26 - Cosmos 398 - T2K s/n 2 - Second LK moon lander test using T2K version. Maneuver Summary: 189 km x 252 km to 186 km x 1189 km orbit, delta V 251 m/s; 186 km x 1189 km orbit to 200 km x 10,905 km orbit, delta V 1320 m/s.

  • 1971-08-12 - Cosmos 434 - T2K s/n 3 - Final LK moon lander test using T2K version. Maneuver Summary: 188 km x 267 km orbit to 190 km X 1261 km orbit, delta V 266 m/s; 188 km x 1262 km orbit to 180 km X 11,384 km orbit, delta V 1333 m/s.

  End of the LK

  A two-crew version of the LK was studied for support of the Zvezda DLB lunar base planned after the initial landings. Space was so limited that special recesses would have to made in the cabin wall to accommodate the helmets of the two suited cosmonauts. However this was a moot point, since the increased payload required major modifications of the engines and propellant tanks, which were specifically designed for the single-crew, 5,500 kg LK. In the end it was decided that this was not practical. Larger lunar landers were instead designed by Korolev's bureau using Soyuz return capsules and descent stages copied from the American lunar module layout.

  Yangel died soon after completion of the successful T2K flights, content that he had done his part for the program.

  LK landers are preserved at the MAI museum in Moscow (this was a flight model that was displayed at Eurodisneyland in 1997), the MAI museum at Orevo (an engineering article), St Petersburg, the Energia plant at Korolev, north of Moscow, and at KB Yuzhnoye in the Ukraine.

  Description of the LK

  At the end of development the LK as designed had a mass of 5,560 kg, with the Block E stage weighing 2,950 kg. Takeoff mass from the lunar surface was 3,800 kg. The total height was 5.2 m. As with most aerospacecraft, the LK must be looked at from both a systems and a module viewpoint.

  LK Modules

  LPU

  The LPU - lunniy posadocnie ustroistviy - was the landing leg assembly of the LK. The LPU was able to handle slopes of 30 degrees with the LK centre of gravity being 2.5 m above the surface. Solid propellant 'nesting' engines fired downward at the instant of touchdown to remove all tipping moments from the spacecraft. Mounted on the LPU were those systems not required after the landing on the moon: the landing altimeter, parabolic antennae, chemical batteries, and three water tanks for the evaporative cooling system (a fourth was added late in development to trim the centre of gravity). A video camera was externally mounted to give the ground a view of surface operations. It may be calculated from data given that the LPU, with its associated equipment, had a total mass of about 1,440 kg (5,560 kg LK mass - 280 kg descent propellant - 40 kg orientation system propellant used during descent - 3800 kg given as LK mass at start of ascent).

  Block E Rocket Stage

  The streamlined shape of the Block E allowed engine exhaust gases reflected from the lunar surface to flow up and away from the LK during landing. The Block E engines were equipped with clamshell doors, which closed at engine shut-off and prevented damage from lunar soil while the LK was on the lunar surface.

  Total Block E mass has been given as 2,950 kg. It was stated that the original specification of 510 kg empty mass for the stage could not be met; assuming a 10% weight growth during development, the empty mass was probably around 550 kg. This would give a propellant load of 2,400 kg (volumetric capacity of the 2 x 1.2 cubic meter tanks was 2,600 kg). Propellant consumption in the landing maneuver was 280 kg, leaving about 2,100 kg for the ascent into orbit. The engines were rated to burn up to 2,900

  Crew Size: 1. Design Life: 3 days. Orbital Storage: 30 days. Length: 5.20 m (17.00 ft). Basic Diameter: 2.25 m (7.38 ft). Maximum Diameter: 4.50 m (14.70 ft). Habitable Volume: 5.00 m3. Mass: 5,560 kg (12,250 lb). RCS Coarse No x Thrust: 4 x 390 N. RCS Fine No x Thrust: 4 x 98 N. RCS Impulse: 245 kgf-sec. Main Engine: RD-858. Main Engine Thrust: 20.100 kN (4,519 lbf). Main Engine Propellants: N2O4/UDMH. Main Engine Propellants: 2,400 kg (5,200 lb). Main Engine Isp: 315 sec. Spacecraft delta v: 2,700 m/s (8,800 ft/sec). Electrical System: Batteries. Electric System: 0.50 average kW. Electric System: 30.00 kWh. Associated Launch Vehicle: Soyuz 11A511L.

• L3M-1970.  Class: Manned. Type: Lunar Lander. Destination: Moon. Nation: Russia. Manufacturer: Korolev.

  The first design of the L3M lunar lander had the crew of two accommodated in a Soyuz capsule atop the lander. They would have had to don space suits to move to the pressurized toroidal crew compartment and land the spacecraft. Sufficient supplies existed for stays of 16 days on the lunar surface.

  The original draft project prior to 1970 for the N1M-L3M lunar landing complex anticipated use of a two-launch profile. On the first launch a Block R TB braking stage would be put on a translunar trajectory. The TB would place itself in lunar orbit. Next, the manned L3M lunar lander would be launched. This new spacecraft was much larger than the LK, with a mass of 21 metric tons landed on the lunar surface. The L3M would dock, tail-first, with the TB stage in lunar orbit. The RTB would act as a lunar crasher stage. The L3M would separate from the TB just over the lunar surface, then hover to a soft landing. The crew would spend up 16 days on the surface. Following completion of their work, the landing legs would be left behind, and the L3M would launch itself on a trans-earth trajectory. Just before arrival at earth, the crew would enter their Soyuz capsule, separate from the L3M, and make a lifting re-entry into the earth's atmosphere. It was felt that within the existing funding allocation of the original N1-L3 program, enough N1's would be available to support a series of landings in 1978-1980.

  In this earlier L3M, the Soyuz return capsule was perched atop the landing stage. A small toroidal crew compartment provided accommodation for space-suited cosmonauts to land the vehicle on the moon. Evidently the crew, which would have been limited to two cosmonauts, would be required to space walk from the Soyuz capsule to the toroidal chamber prior to the landing attempt. A return spacewalk would have to be made after ascent from the surface. This L3M had a landed mass of 21 metric tons on the surface, an ascent mass of 18 metric tons, a trans-earth injection spacecraft mass of 5 metric tons, and sufficient supplies for 14 to 16 days of operations on the surface.

  Crew Size: 2. Design Life: 14 - 16 days. Length: 7.90 m (25.90 ft). Maximum Diameter: 4.50 m (14.70 ft). Span: 7.30 m (23.90 ft). Mass: 23,000 kg (50,000 lb). Associated Launch Vehicle: N1M.

• OS-1 Lunar.  Class: Manned. Type: Lunar Orbiter. Destination: Moon. Nation: Russia. Manufacturer: Korolev.

  A version of the OS-1 station was proposed for use in lunar orbit. No other details beyond this sketch.

  Length: 29.00 m (95.00 ft). Maximum Diameter: 6.00 m (19.60 ft). Associated Launch Vehicle: N1.

• 1968 February 27 - Soviet on plan through 1975 for automated probes to the moon and planets. -

  Keldysh heads a Soviet on plans through 1975 for automated probes and space research of the moon and planets. Barmin attends, his interest being the relation of this work to his lunar base. Kamanin finds the plan not well thought out... Tereshkova sees Kamanin and tells him she cannot handle the stress of both political demands on her time and cosmonaut training. She wants Kamanin's assistance to get her out of political tasks.

• Semenov, Yu. P., S P Korolev Space Corporation Energia, RKK Energia, 1994. ISBN: 1896522815. Dual English/Russian language picture book of the history of the Energia Corporation. Many unique photos and drawings of Korolev's rockets and spacecraft. Republished by Apogee books in 2000. More at amazon.com...

• Zaselskiy, Vladimir, and Chernisheva, Olga, Ogonyok, "Proyekti XXI veka", 1997-04-17, No. 15.

• Rebrov, Mikhail, Krasnaya Zvezda, "Orikosnoveniye k legende o 'DLB'", 1996-06-11.

• Kamanin, N P, Skritiy kosmos, Infortext, Moscow, 1995. The diary of the Commander of the Soviet Cosmonaut Team in the 1960's - a source of great insights into the space program. Four volumes issued to date.