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Space


Lunar Ship LK

The N1-L3 project was too large for one enterprise (in the US, Apollo had more than 20,000 organizations). OKB-1 Korolev was appointed chief for N1-L3. The lunar ship itself was commissioned to develop the OKB-586 (Yuzhnoye Design Bureau in Dnepropetrovsk), and Yangel was appointed head of this unit.

In general, the project N1-L3 was completed on December 30, 1964, at the same time the preliminary deadlines for the implementation of all stages were appointed. The first launch of N1 was to take place as early as 1966, and the first cosmonaut on the Moon would have landed as early as 1967-68, which would make it possible to get ahead of the Americans who appointed the landing for 1969.

But as soon as Yuzhnoye began the detailed development of the lunar ship, it turned out that previous estimates of the mass of the LK turned out to be greatly underestimated, and it was not possible to keep within the previously established mass. This happened because of a too rough approach to the LK in the draft approach. For example, the horizontal speed of the device during landing did not actually allow the radar altimeter, which was planned to be installed on the LK, to determine the actual height. The velocity of the vehicle, estimated at one of the flight sites at 30–40 m / s, would actually be 200–300 m / s. In the first version, the LK weighed only 2.2 tons, and it was designed for two people. To eliminate these and other shortcomings, we had to increase the mass of the vehicle to 5.5 tons, and reduce the crew to one person.

Initially, Yangel wanted to leave room for a second cosmonaut in the lunar cabin, but still it turned out to be impossible. Weight reduction was the main task facing designers, for each innovation that would reduce the weight of the lunar ship by one kg, a premium of 60 rubles was appointed. Improving some systems of the orbital part, it was possible to reduce the mass by only 500 kg.

Determining the current speed and height after the separation of the D-block also proved problematic. The amount of fuel needed and all related parameters, such as the location and shape of the fuel tanks, depended on how efficiently this system worked.

The created radar system was called "Planet". She had four antennas. The first three created the rays, separated from each other by 120 o, and by changing the frequency of the signal due to the Doppler effect, it was possible to accurately determine the horizontal speed of the ship. The fourth antenna is directed perpendicular to the surface and served to determine the height. Such a system turned out to be relatively simple and reliable, and although it did not work for its intended purpose, Planet showed its reliability during the AMC E-8 flights (automatic delivery of lunar soil to Earth).

When conducting tests of the radar on board the MiG-17, some problems were found that could be solved. Due to limitations, Mishin (who continued working for the deceased Korolev) allows to place only 280 kg of reserve fuel, which also delays the creation of an altimeter radar, which must now very accurately measure to avoid excessive fuel consumption.

In 1967, Yangel informs Mishin that the lunar ship will be ready no earlier than 1971 (that is, three years late). In 1968, the program again undergoes changes. Initially it was planned to land at the lunar equator, i.e. the lunar orbital spacecraft would be in equatorial orbit and would fly every hour over the landing site of the lunar cabin. This greatly facilitated the convergence and docking of vehicles, but at the same time, the most interesting places for landing are not always located exactly at the equator. If another place was chosen, the procedure of approaching the lunar compartment (after its launch from the moon) and the lunar orbital ship, which could be above the landing place 2-3 times less, became more complicated. In this case, there were three options:

The lunar ship was equipped with an accurate inertial navigation system, which allows to perform complex maneuvers in circumlunar orbit for docking with the orbital ship. After the launch from the surface, the lunar ship gradually changed its orbit until it was combined with the orbiter. In this case, no complicated navigation equipment was required. The lunar ship calculated in advance the trajectory of convergence even before launching from the Moon, and, having started from its surface, carried out docking according to a calculated scheme.

The Americans chose the first option, in the Soviet program they preferred the second one. Docking was supposed to take place at an altitude of 25-30 km. Since the digital computer could not be used for these purposes (because of its absence), an analog system was developed that calculates the necessary elements of the orbit and the moments of switching on the propulsion system. Such a system for the lunar ship was created and was very effective. In contrast to these tasks, the task of maintaining the center of mass was very difficult. The center of mass should not have moved more than 3 cm (!). This required a special arrangement of the fuel tanks of the E-block and engines of precise orientation. The cosmonaut in the lunar cabin was also severely constrained in his actions. All equipment LK also had to develop and place in accordance with these requirements.

That part of the apparatus, which directly touched the surface, was called the abbreviation LPU (lunar landing device). In addition to ensuring the landing, this module served as a launching pad for block E, with the help of which the lunar ship took off from the moon. The hospital also housed equipment that was activated only during the descent or it could work in lunar conditions and was used before take-off from the surface. It was a radar altimeter, parabolic antennas, chemical current sources, three tanks (a fourth was later added) with water for an evaporative cooling system and a video camera that would shoot an cosmonaut on the surface. The hospital had a mass of 1440 kg with a total weight of the lunar spacecraft of 5560 kg.

Due to the mass limitation of the apparatus, the propulsion system could move the ship no further, than 100 meters from a pre-selected point. This place could be quite large craters, so the lunar landing device had to ensure a normal landing (and subsequent take-off) to the surface so that the device could function normally even when it formed rather large angles with the surface (up to 30 degrees) . It was also necessary to ensure the "blind" landing of the device in unmanned versions, when the absent cosmonaut could not control the operation of automation.

Before the designers there is a question: with what exactly should the apparatus touch the moon? The minimum option was the use of three landing pillars, such a scheme was used for landing on the moon of their "Surveyors" (automatic devices for research and photographing the surface). This option was not suitable for the Soviet lunar ship, since it did not provide the necessary stability and did not guarantee the preservation of the center of mass. Health facilities start to develop several design offices at once, and a large number of different projects appear: from several supports to a special landing ring.

In the end, there were two possible schemes: passive and active. In the first case, the device would land on several passive supports, but then it was necessary to ensure a very smooth approach to the surface. In the second case, the landing bearings had their own corrective engines, which were switched on directly at the moment of contact for precise positioning of the vehicle.

For the final choice, a whole complex was created to simulate landing on the lunar soil: a large room was filled with volcanic tuff from Armenia (in its physical properties it resembles lunar regolith), and an imitation of the tangency of the Moon was carried out in it. Tests have shown that an active circuit is preferable (solid-fuel engines were used), which was chosen for the lunar ship.

The moon cabin was designed to accommodate one cosmonaut. In the center (relative to the cosmonaut sitting in the cockpit) there was a large window in which observations were made during the landing. Above it was another window that was to be used to observe the docking process with the lunar orbital ship. The most important controls of the device were to the right, and less so to the left of the person sitting inside. An additional requirement for the developers was that the LK should have been capable of an unmanned flight: it automatically sits on the moon and automatically docks with the orbital ship. This was required both for testing the apparatus in an unmanned mode and for carrying out possible "rescue" operations, when, in the event of a damage to the E block, the LK could not take off from the moon and the cosmonaut remained on the surface. This required, of course, the simultaneous launching of two vehicles to the Moon: a worker (manned) and a backup. The autonomy of the lunar ship was provided by television cameras, which allowed to see everything happening on Earth and remotely control the spacecraft.

Originally in the lunar cabin was supposed to use pure oxygen under a pressure of 0.4 atmosphere. But it was too flammable environment, therefore, subsequently the share of oxygen, adding nitrogen and increasing the pressure to 0.74 atmospheres. At the same time, although it was required to increase the mass of air reserves by half, however, the ship became safer in terms of fire hazard. At the last stage of the landing of the lunar cabin, as already mentioned, the cosmonaut took over the management. However, at the time of development of the landing gear, the creation of such a system was hampered by a complete lack of experience. Everything had to start over. In addition to maintaining the center of mass, it was necessary to ensure full performance even in the event of possible depressurization of the cabin. Although all systems at depressurization were supposed to remain intact, the spacesuit was designed only for 10 hours. In this case, it was necessary to immediately return to the lunar orbital ship. In this regard, they had to abandon the use of foot pedals. Developers had to study the experience of aircraft designers, who created in those years vertical take-off and landing aircraft.

The options for locating dashboards and portholes were also worked out for a long time. It was found that for viewing the surface of the moon when replanting, the optimal viewing angle is 7 degrees. The porthole, which uses to control the descent, had a coordinate grid for determining and correcting the place of contact of the ground. Designers also had to create a spacesuit that allowed working directly on the moon for quite a long time. It was named "Krechet" and became the prototype of the Orlan spacesuits, which are used today by Russian cosmonauts to work in outer space. The Merlin, as well as its today's counterpart, Orlan, was a very complex device. A cosmonaut did not put on the suit, but on the contrary, the man entered the spacesuit - for this, there was a hatch in the back of this equipment.

Automatic control system, the bases of which were taken from guidance systems from military missile complexes, provided control of the ship at all stages of the flight of the lunar module: descent, landing, takeoff and docking. All the calculations necessary for the operation were provided by the onboard computer (onboard electronic computer), which processed the data from the measuring sensors and gave instructions to the propulsion system. Basic orientation data provided gyros and radar, measuring the horizontal and vertical velocities of the device. The cosmonaut had the opportunity to correct the commands issued by the on-board computer, and he also saw near the surface the point at which the device sat down (using special symbols on the window) and could change it (choose a new landing place, located not further than 100 meters from the old place). All calculations were performed in three independent parallel streams to reduce the number of possible errors. Radar system for measuring the speed of the device was located outside the spacecraft near the equipment for access to the lunar surface.

Docking system "Contact" was lightweight and provided simple physical contact and capture of ships. "Contact" could work both manually and automatically. Power distribution system. It is located in the lower instrument compartment. It consisted of a system of electrical cables and five chemical batteries: three in the hospitals and two in the lunar cabin. These electric batteries had a relatively long shelf life: they could be used for their intended purpose even after three months in space. Analyzer remaining onboard systems that determine their health. Cabin for an cosmonaut. On-board computer was used in the automatic control system with a speed of 20,000 operations per second. Provided parallel computations of three independent data streams. Antenna disclosure system. Antennas themselves: two meter parabolic antennas for high-speed data transmission and broadcast of television images and one omni-directional antenna for communication at low speed with the Earth and the lunar orbital ship.

TV cameras are intended to transmit frames of the lunar surface during the landing of an unmanned vehicle and to transmit the video image of an cosmonaut going to the lunar surface and working on it. A system that transmits telemetric data on the operation of all ship systems. The suit "Krechet" provided access to open space and to the surface with an autonomy of 10 hours. The system maintains the atmosphere of the lunar cabin. The thermoregulation system, which provides a normal temperature at a temperature outside the lunar apparatus from +130°C to -200°C.

A very close attention was paid to the propulsion system, which was designated by block E and was intended for a soft landing and take-off from the moon. Already at the first sketches of the lunar ship there were drawings of this block. Originally planned to meet 510 kg, however, it soon became clear that this was unrealistic.

For reliability, the E unit had not one, but two engines: the RD-858 and the RD-859. As soon as block D was separated from the apparatus, they were launched simultaneously. If automatics noticed any failures in the first engine, it immediately turned off, and the landing gear returned on the second, spare engine to the lunar orbital ship. If everything was normal, the lunar module continued to decline on the main engine, while the second remained in reserve at that time. It is clear that would cause the failure of two engines at once. In the mode of reduction, it was necessary to develop a draft of 850 kg, and in the mode of take-off - 2000 kg. The RD-858 could change its power within these limits, and the RD-859 had a fixed value of 2000 kg, i.e. landing with him was impossible. Throughout the operation of unit E, 2900 kg of fuel was supposed to burn out.

Creating a reusable motor with adjustable pitch required titanic efforts. For its development it was necessary to invent new materials and technologies. A key problem in the development of block E (as well as the lunar landing gear) was the "reflection" of gases flowing from the nozzles from the lunar soil during landing. In the American Apollo, various engines were used for landing and take-off, which made the task much easier. A similar option in the Soviet project was not possible due to limitations on the mass of the entire apparatus. If, in the case of the American lunar module, the soft landing engine was clogged or damaged upon contact with the surface (which happened several times), then it did not matter. For the moon ship had to develop a system which sent a jet stream of gases in the immediate vicinity of the surface as far as possible from hospitals. When the E block was turned off (in the “landing” mode), the nozzles were immediately closed in order to avoid foreign particles, such as lunar dust, which rose when the ground touched it.

To preserve the center of mass of the fuel tanks (with a volume of 1.2 m3 each), it had to be given an unusual shape: the oxidizer was consumed 2 times faster than the fuel. Long-stored self-igniting components, hydrazine and nitrogen tetraxide, were used as a fuel / oxidizer. The mass of the fully charged unit E was 2950 kg, the empty stage weighed about 550 kg. For a soft landing, it was necessary to burn about 700 kg of fuel, and for takeoff, 2100 kg were required.

For corrective maneuvers a separate propulsion system was intended. As in block E, it used hydrazine / nitrogen tetraxide. It was located above the lunar cabin and could provide not only horizontal, but also vertical corrections. For increased reliability, the lunar ship had not one, but two independent orientation systems, and could work even in the case when one of them completely failed. For their operation, there were 100 kg of rocket fuel components. As in the case of the main fuel tanks, it was necessary to tinker with the center of mass: a tank with an oxidizer was placed inside the fuel tank and had a special structure.

To supply fuel to fuel tanks, helium was pumped up under a pressure of 10 atmospheres, displacing the liquid from the tank. The engine could be turned on many times, the duration of the minimum impulse was 9 milliseconds, the maximum - 10 seconds. For nozzles placed at an angle of 20 degrees to the horizontal, a new graphite-niobium alloy was used.

On top of the entire ship, in addition to the orientation system, there were radiators of the thermal control system and the seizure of the docking station.

To test the spacesuit (as, indeed, and not only him), a full-scale mockup of the lunar ship was built, on which various tests and trainings of the crew were conducted. Probably many have seen these shots in the chronicle. In order to imitate the lunar gravity, which is 6 times the earth's, a special inclined tower was built. The man walked along its outer wall, which formed an angle of about 30 degrees with the vertical. At the same time, the gravitational pull pulled down and took most of the weight (so as not to fall, the person in Krechet was hung up on a rope before these operations), and only one-sixth of the weight remained on the support, which provided "lunar conditions". Since the spacesuit turned out to be quite large, designers had to re-develop the hatch.

In order to save mass, the docking station had a fairly simple device (compared to the same node, in Soyuz, flying in near-earth orbit). This simultaneously reduced the cost of the device and increased reliability. Since the cosmonaut moved from the lunar orbiter to the landing module and back during the spacewalk, there was no need for any rigid docking to ensure a tight transitional tunnel between the modules. Developed for this purpose, the system "Contact" provided a simple approach of the vehicles (after the launch of the lunar ship from the moon) and their mechanical capture.

This system should have been developed and tested by 1968. It was planned to launch two "Soyuz" in unmanned mode to work out the docking, after which a similar flight of the manned "Unions" was to be carried out. However, unmanned attempts failed, and the launch immediately after that of the Soyuz-1 with Komarov also ended in tragedy: he was killed when landing on Earth. Instead of four "Unions", more than a dozen vehicles were spent, and the Soviet lunar program was delayed (though not only because of this) by a year and a half. Kontakt was fully operational only during the Salyut program (manned orbital stations), more precisely, by October 1971. Together with the orientation-stabilization system and the fuel for it, the lunar cabin weighed about 1,300 kg.

Due to the limitations of the mass of the LK, it was not finally chosen, but it is clear that the main "scientific experiment" until 1969 was the installation of the Soviet flag on the Moon before the Americans set their own.

N1-LK3



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Page last modified: 22-03-2019 21:48:47 ZULU