Post 7: N-1 Developments
“We do not want to retrace the Americans’ path. We must have forward-looking plans.”
- Minister of General Machine Building, Sergei Afanasiev, 6 December 1969
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The success of the N1-8L mission was a cause for elation amongst the TsKBEM engineers who had worked on the lunar mission for so many years, and for much of that time had known only failure. Despite the loss of Soyuz 7K-LOK No.2 en-route back to Earth, the impressive achievement of placing the LK on the lunar surface - under fully automatic control, no less! - seemed to open the way to putting a cosmonaut on the surface years earlier than the L3M programme could achieve. True to his earlier form, in March 1974 Mishin proposed to the VPK that, if the upcoming N1-9L mission was completed successfully, then the next mission should attempt to put a man on the Moon using the L3 approach.
Despite the superficial attractiveness of this option, there were several influential voices speaking against it, including from within Mishin’s own bureau. Several of his senior deputies, including Feoktistov, Semenov, and others, were concerned at diverting resources away from the L3M project in favour of the far more limited dead-end of an L3 landing. This opinion was shared by Mstislav Keldysh, head of the USSR Academy of Sciences, who had long opposed L3 as being scientifically useless. Keldysh, who was now approaching the end of his long and illustrious career, had backed L3M, and was loath to see it delayed any further.
Further concerns were raised by Nikolai Kaminin[1], the head of the Cosmonaut Training Centre for the Air Force, who remained unconvinced that the L3 system could be made safe enough to risk the lives of cosmonauts. In his view, the large number of critical events and the razor-thin safety margins inherent to the system made it an accident waiting to happen. The failure of the LOK habitation module separation on mission 8L appeared to validate this view.
In the end, the VPK agreed, and decided to continue with the flight plan as laid out for L3M. Mishin still held out hope that a successful follow-up to 8L would enable him to persuade the leadership to be more daring, but these hopes were dealt a blow when N1-9L launched in August 1974. Carrying another LOK/LK pair on a similar mission profile to 8L, all appeared well until the time came for the Blok-G upper stage to send the L3 stack on its way to the Moon. The stage failed to ignite, leaving the Blok-D, LOK No.3 and LK No.2 in an Earth parking orbit. The mission was not a total loss, as it proved possible to separate the Blok-G from the rest of the stack and perform the various planned manoeuvres with the LK and LOK in Earth orbit under the designation “Kosmos-676/7”, but it lent further strength to Kaminin’s argument that the L3 system was not ready to fly cosmonauts.
By this time, four years after the VPK had approved the L3M project, good progress was being made on developing the Blok-Sr upper stage, GB-1 lunar “crasher” stage, and crewed GB-2 Lunar Expedition Ship (LEK) that would be used for the mission.
Blok-Sr was to be the largest hydrolox stage developed by the USSR to that point, making use of an upgrade of the RD-56 engine developed by Alexei Isaev’s OKB-2 Design Bureau (re-named KM KhimMach in 1974). This upgrade had originally been intended for use on the smaller Blok-R for an earlier upgrade of the N1, and had carried over to the Blok-Sr when that stage merged the roles of the old Blok-S and Blok-R. A particular challenge was the requirement to be able to re-start the engines up to five times over the course of a mission, in order to perform the Earth departure, mid-course correction, and lunar capture manoeuvres that would put the GB-1 and GB-2 into orbit of the Moon, but by 1974 Isaev’s team were confident that they had solved these issues. Initial test firings showed good results, and Isaev was expecting to be able to deliver an integrated Blok-Sr stage with two RD-56 engines for a test flight by mid-1975.
In order to support such a mission, it was necessary to upgrade the facilities at the Groza launch pads to support liquid hydrogen production, storage and fueling operations. To this end, Vladimir Barmin’s Design Bureau of General Machine-Building (KBOM) had in 1973 begun construction of a new hydrogen propellant and storage facility half a kilometre northeast of the twin launch pads at Baikonur Site 110. These would pipe the super-cold propellants for the Blok-Sr via a new fueling arm on the Rotating Service Structure towers at each launch pad.
With Pad 37 (the West or Right launch pad) supporting ongoing Groza launches, the tower modifications were first started at Pad 38 (Site 110 East or Left). Following its devastation in the explosion of N1-5L in July 1969, the launch pad had been painstakingly rebuilt, and would now be further modified to support L3M. In addition to the provisions for liquid hydrogen, this also involved modifications to the umbilical connects and the crew access arm that would be used with the L3M GB-2 spacecraft. This meant that, for the next few years, Pad 37 would remain the sole launch pad for Groza missions. After completion of the upgrade at Pad 38, the pads would swap roles as Pad 37 was upgraded in its turn, resulting in a dual-launch capability being restored by the end of 1976.
For the spacecraft themselves, the 24 tonne GB-1 ‘crasher stage’ was maturing rapidly. This was to be expected, as it was basically a stretched version of the Blok-D that had been in use since the first Proton/Zond mission in 1967, and which had given sterling performance on the N1-8L/Zond-10 mission. GB-1 would use the same 11D71 engine burning kerolox propellants as Blok-D, and TsKBEM expected to have the first flight model ready for launch by the end of 1974.
By far the most complex component still to be developed was the GB-2 Lunar Expedition Ship (LEK). Projected to have a mass of more than 23 tonnes on the lunar surface, the GB-2 dwarfed the six tonne LK lander used for L3. This was partly due to the tripling of the crew compliment, but also related to the fact that LEK would also replace the function of the LOK, being a single vehicle for the journey to lunar orbit, landing and habitation on the Moon’s surface, and return to Earth.
Working backwards from the end of the mission, the Return Capsule (VA) was a modification to the familiar, headlamp-shaped Soyuz module that had been used on all of the 7K variants, including the LOK. For most of the mission, the Return Capsule would be housed within a pressurised ‘hanger’ formed by the Cocooned Habitation Block (OB), with the VA suspended from a hatch at the top of the OB, which in turn connected to the Escape Tower during launch. The three cosmonauts would remain in this capsule for launch and re-entry phases of the mission, but the rest of the time would be able to exit the VA through a side hatch and move around the OB, removing the need for spacewalks or complicated (and heavy) docking mechanisms and hatches.
The Cocooned Habitation Block would be the cosmonauts’ cockpit, main workspace, and home during the 2-3 weeks of the L3M mission. The module was spherical in shape, with two bowl-shaped depressions for windows, affording the Commander and LEK Pilot a downwards view from which to control the descent and landing. On the other side of the module was an exterior hatch for access to the lunar surface. Weight and volume limitations meant that it was not possible to include an airlock in the OB, and so for moonwalks one of the cosmonauts would seal themself inside the Return Capsule, while the other two donned moonsuits and depressurised the main cabin of the OB. Space was tight in the Habitation Block, with the Return Capsule taking up much of the interior volume, but it was roomier than the capsules already used for the long duration Soyuz 9/10 mission, and so Semenov’s team were confident it would be sufficient.
The Habitation Block was mounted atop a Propulsion Unit (DU) carrying a large main engine using a hydrogen peroxide/hydrocarbon propellant mix. This engine would be responsible for all vehicle manoeuvres from final descent through to lunar ascent and trans-Earth injection, and so reliability was vital. In an unusual case of cooperation between bureaux, the RD-510 engine for the DU was being developed by Glushko’s NPO Energomash. The DU would also house the fuel cells that would power the spaceship for missions of up to a month. Based on those developed for the L3 LOK, they would provide both power and drinking water for the crew during their mission.
The combined VA/BO/DU complex was attached to a disposable Landing Stage, consisting of a framework mounting the landing legs, batteries, scientific equipment, and radiators. This would be left behind on the surface at the end of the mission, removing the need to lift almost four tonnes of equipment back to lunar orbit. Before descending to the surface, the Landing Stage would also carry a Kontakt docking system and associated rendezvous antennas and cameras. Derived from the system developed for the L3 LOK and LK, and tested in Earth orbit on the Soyuz 9/10 mission, this would be used to link the LEK to the GB-1 crasher stage in lunar orbit. Following the completion of GB-1 descent burn, the Docking Module would detach from the Landing Stage and impact on the lunar surface with the GB-1 booster.
The development of the LEK was led by Yuri Semenov’s team at TsKBEM, and was proceeding well, taking advantage of many of the systems developed for the L3 programme. Nevertheless, the complexity of the new spacecraft meant that the first uncrewed test flights were not expected to take place before 1977, putting the earliest date for a crewed mission into 1978. Before that date, there were two other major programmes planning to make use of Groza’s heavy lift capability: a series of uncrewed heavy Mars probes, and the long-delayed MKBS space station.
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[1] IOTL, Kaminin was retired after the Soyuz 11 disaster, having previously avoided forced retirement in 1969. ITTL, he is still in-post at the age of 67, and still fighting political battles with Mishin.