Whilst the complexities and expense of a lunar landing mission always looked difficult for the Soviet space programme to achieve before the end of the 1960’s, the possibility of a simpler circumlunar flight certainly seemed within reach. Unfortunately one of the fundamental truths of the Soviet programme was that the so called Space Race was in reality always as much an internal  battle for influence and funding between the competing design bureaus as it ever was a clash between superpowers.

But in spite of missed opportunities, tragedies and political indecision this was a race that nearly went right down to the wire.

Setting the scene
In December 1959 the Central Committee of the Communist Party had issued a decree titled On the Development of Research Into Cosmic Space. Although issued in response to approaches from Korolev and other Chief Designers including Valentin Glushko, the decree was short on actual commitments to projects, setting in place a number of general themes for exploration. Korolev had hoped for more and immediately began lobbying for an extended decree which would commit to more defined goals and establish an official body to oversee the Soviet programme – a similar role to that performed by NASA in the United States.

After direct approaches to Khrushchev and much jockeying between the Chief Designers a new decree was prepared, issued by the Central Committee in June 1960 as On the Production of Various Launch Vehicles, Satellites, Spacecraft for the Military Space Forces in 1960-1967. While stopping short of the creation of a Soviet space agency, it did allow Korolev to move ahead with his plans for his N-1 and as a step towards the mastery of interplanetary travel OKB-1 began exploring ways to perform a circumlunar flight.

Early plans at OKB-1
Although it was clear that the N-1 and it’s ability to boost much heavier payloads into orbit were many years away, what was available at the outset of the 1960’s were the R-7 derived boosters used for the Vostok and Luna programs and the initial designs for a new generation of crewed spacecraft. Using these, engineers within OKB-1 put together their first plan for a manned circumlunar flight – Vostok-7/IL.

The Vostok-7/IL plan [IMG: Chris Petty]
In hindsight we can view the plans for Vostok-7/IL as a rather unrealistic and over complex way to try and reach the Moon, but at the time they represented the best that could be done with the technology at hand. Realising that it would be impossible in the short to medium term to launch a single craft capable of undertaking a circumlunar mission, OKB-1 instead opted for a complex mission profile involving multiple launches and the construction of the IL complex in Earth orbit. Once completed, this could then be boosted out of orbit and complete a circuit around the Moon before returning directly for re-entry and subsequent landing in Soviet territory.

The plan would require a new manned ship, but also feature a modified Vostok. The new IL ship would carry two cosmonauts and feature many of the characteristics later to become familiar on the Soyuz vehicle such as separate living, re-entry and instrumentation modules as well as solar panels to provide electrical power. It would also feature a conical arrangement of small thrusters to allow for orbital manoeuvres required for rendezvous and docking, necessary as the IL would need meet up with the rest of the circumlunar complex once in orbit.

The remainder of the complex was comprised of 3 propulsive blocks, each to be launched separately and constructed into a propulsive train by an engineer cosmonaut who would have launched previously in the modified Vostok-7. This craft would need to rendezvous with each rocket block as it reached orbit, make sure they docked and connected correctly and then remain on-station until the IL had docked at the other end of the complex. At this point the Vostok-7 could detach and return to Earth as the IL began it’s journey to the Moon.

The design process for the Vostok-7/IL mission was completed early in 1962 and submitted for consideration, but unsurprisingly the idea of a circumlunar mission that required 5 separate launches, 2 manned craft and 4 dockings failed to win much support outside of OKB-1. Undaunted, Korolev’s bureau began work later that year on a refined plan which was ready for March 1963. This was the 7K-9K-11K scheme and marked the first use of the 7K Soyuz craft.

The Soyuz we now recognise emerged from the amalgamation of the IL plans and a separate initiative within OKB-1 for an orbital craft named Sever. Whereas the re-entry module on the IL had been essentially cylindrical, Sever was to feature a stretched hemispherical ‘car headlight’ shaped module which would allow for a controlled lifting re-entry. This would be important when returning at high-velocity from the Moon as it would allow a double-dip re-entry bleeding off much of the speed without exposing the crew to excessive G-forces during deceleration.

A skip re-entry profile as used when returning from lunar flight [IMG: Wikipedia under CC license]
As with the earlier plans, 7K-9K-11K relied on multiple rendezvous in Earth orbit, this time with a succession of at least four 11K tankers, each of which would transfer it’s load of fuel and oxidiser to the 9K propulsive block. Once fuelling was complete, the manned 7K and 9K booster stage would be propelled on a trans-lunar burn. Interestingly in this plan the Cosmonauts would be facing away from the direction of travel so would have been subjected to a period of negative-G during acceleration. A similar arrangement was used during American Gemini flights when the engine of the Agena docking target was used to boost the docked craft to higher orbits.

The 7K-9K-11K Lunar Complex [IMG: Chris Petty]
The 7K-9K-11K plan was given official approval in December 1963 and contracts were distributed to other design bureaus by OKB-1 for the 9K and 11K elements. But this work was to be short lived. Korolev’s position as the Soviet Union’s pre-eminent space designer had been waning for many years. He had hoped work on Soyuz and the circumlunar flight may reverse his fortunes as development of the N-1 continued, but he had a charismatic rival who also had his eyes set on the Moon.

The Rise of Chelomei
To western eyes, it’s easy to imagine that in the wake of the successes of the Sputniks and early planetary probes that there was real momentum building in the Soviet space programme. Surely the mastermind behind these triumph now found themselves in a unparalleled position with the full support of Soviet Politicians? In truth even before Gagarin’s historic flight in Vostok 1 on April 12 1961, Korolev’s position had begun to be usurped by a relative newcomer – Vladimir Chelomei. Whereas Korolev and his contemporaries Yangel and Glushko had gained their influence by providing the Strategic Missile Forces with the IRBM and ICBMs they demanded, Chelomei came from the aviation sector. Having suffered early reverses he nonetheless managed to establish a new design bureau, OKB-52, based on proposed cruise missile designs. Soon his mind turned to space and he gained a strong patron in the shape of Premier Nikita Khrushchev.

Vladimir Chelomei, Designer of the UR-500 and UR-700 rockets [IMG: Wikipedia CC License]
Whereas Korolev was an incessant driving force able to push his ideas into reality through sheer force of will, Chelomei seemed much more comfortable courting influential figures and selling them his ideas regardless of his lack of a track record. It certainly didn’t harm his prospects when he hired Khrushchev’s son Sergei to work within OKB-52 and soon he was able to use the access this granted him to push his preferred themes for space exploration. By the time of the June 1960 decree, his name was already established enough that his proposals were considered on an equal footing to Korolev’s and by 1961 his plans for a new family of boosters under the designation Universal Rocket (UR) and a series of manned and unmanned exploratory spaceplanes under the Raketoplan and Kosmoplan themes were given top priority, with funding allocated at the expense of OKB-1’s ongoing projects including the N-1. Interestingly he took the title General Designer, common in aviation bureaus rather than Chief Designer, more associated with the missile and space related bureaus.

Seemingly it didn’t take long for Chelomei to devise a circumlunar plan using one of his spaceplanes and there is some evidence that this was presented to Khrushchev directly rather than submitted through the usual channels. In spite of his expansive ambitions, 1963 saw Chelomei’s planetary plans begin to change. Progress on his Kosmoplans and Raketoplans had moved slowly and the Soviet Military were showing frustration that they had nothing to show for their investment after 2 years. External factors were also at play as the American Air Force’s Dyna-Soar faced cancellation causing questions as to the viability of Chelomei’s competing systems. By late 1963 a revised plan was presented featuring the UR-500 launcher along with a new spacecraft, the LK-1.

An official decree was issued in May 1964 supporting the LK-1 and this decision was reinforced by the 1964 decree, On Work on Research on the Moon and Outer Space which formalised the Soviet decision to pursue unrelated circumlunar and lunar landing programmes in parallel. While Korolev had hung onto the moon landing with his N-1/L3 plan he now knew he had lost the circumlunar mission in spite of earlier decisions in favour of OKB-1’s 7K-9K-11K plan. Chelomei was now tasked with sending the first Cosmonaut around the Moon in time for the Fiftieth Anniversary of the October Revolution in 1967.

The LK-1 Plan
The LK-1 mission differed significantly from the earlier offerings emanating from OKB-1. Rather than building a lunar complex in Earth orbit prior to Trans lunar Injection (TLI) Chelomei realised that with by using a three stage variant of his Proton booster, the UR-500K, he could place a payload of approximately 18 tons into orbit meaning he could achieve a circumlunar flight with a single launch. The relative simplicity of this approach compared to Korolev’s 7K-9K-11K plan had obvious appeal. The LK1 ship itself comprised of a TLI stage (BLOK A), an instrument/aggregate compartment – much like the Apollo Service Module (BLOK B) and the crewed return apparatus (BLOK V). The stack would be topped off by a launch escape system (BLOK G) the first time such a system had been used on a Soviet spacecraft. A powerful escape system was all the more vital given the toxic storable propellants used in the UR-500.

The BLOK V capsule was essentially a truncated cone. Sergei Khrushchev has spoken of Chelomei becoming enamoured with the American Gemini vehicle and deriving some inspiration for the LK-1, although visually the first impression is more of the Apollo Command Module. The capsule’s internal volume was small and its initial configuration would only allow for a single Cosmonaut to undertake the week-long circumlunar mission. Work was later done to enlarge the vehicle and it became the basis of the VA component of Chelomei’s TKS and Almaz projects.

Chelomei’s LK-1 and Launcher

It seems little information was shared between OKB-1 and OKB-52 regarding spacecraft systems, so Chelomei’s engineers had to start from scratch in terms of life support and navigation. The draft plan for the LK-1 was complete by July 1965 and Chelomei hoped to move to production and flight testing as soon as possible given that the UR-500 Proton completed it’s maiden flight that same month. But as was so often the case in the Soviet space programme, external political events were about to cause a change of plans.

Post Khrushchev
While Chelomei’s fortunes had prospered since 1960 under the enthusiastic patronage on Nikita Khrushchev he was inextricably tied to the Premier in the minds of many of the Party and Military leaders. So when Khrushchev was ousted from power during October 1964, the effect on the General Designer and OKB-52 was immediate and marked. Many of his programmes were suspended or cancelled and his progress on the LK-1 soon came under the spotlight.

Eager to regain control of the circumlunar flight and consolidate the entire manned lunar programme under OKB-1, Korolev went on the attack. Logically he felt that using the developing 7K Soyuz as the basis for both projects would save time and resources – both becoming increasingly scarce as the decade, and Apollo, moved on relentlessly. He proposed that the circumlunar scheme could be achieved using his N-II booster (essentially an N-1 minus its BLOK A first stage) and a Soyuz derived spaceship. The additional push needed for TLI could be provided by the BLOK D stage already being designed for the L3 lunar landing.

By August 1965 it seemed Korolev had prevailed with a detailed examination of the LK-1 concluding that it would be unable to fulfil it’s mission by the all important October 1967 Anniversary. But although construction of the circumlunar complex would fall to OKB-1, the Military Industrial Commission decided that the UR-500 Proton was too important an asset to cancel and should remain attached to the programme. So as 1965 drew to a close an uneasy marriage was brokered between OKB-1 and OKB-52 and the two designers as new plans were drawn up.

The 7K-L1 ‘Zond’ 
As 1966 dawned, Korolev finally found himself back in control of the Soviet manned programme. Although the decision to retain the Proton was a setback, he could finally forge forward with the circumlunar and lunar landing programmes. There was the ongoing distraction of the stopgap Voskhod programme and the military requirement for specialised flights of this craft, but finally funding was appearing to get Soyuz  – the lynchpin vehicle behind both L1 and L3 programmes – and the mighty N-1 moving toward flight.

The L1, while based on the 7K Soyuz design, would be severely constrained by the weight restrictions of the UR-500K launcher. With the need to include the BLOK D TLI stage mass was critical and so major modifications were made. The most significant difference was the omission of the Orbital Module, the forward section of the 7K Soyuz. Again, as with the LK-1 this meant the journey around the Moon would be somewhat cramped for the crew. Other changes included upgraded navigation systems, additional hi-gain antennas for communications with Earth, smaller solar panels and the omission of the reserve parachute system. An improved heatshield would also be included to cope with the higher velocities to be encountered during re-entry.

The OKB-1 L1 and Launcher

Following launch, the L1 complex would be checked out to ensure correct operation of systems then BLOK D would ignite for the TLI burn. The vehicle would then travel to the Moon, looping around it and returning directly to Earth. Unlike in the L3 plan, there was no provision to brake into Lunar orbit. This ‘figure-8’ plan was similar to the Free Return trajectory employed by NASA for lunar Apollo flights. On it’s return to Earth the L1 re-entry module would perform a ‘double-dip’ skip re-entry to reduce the craft’s velocity and maintain manageable G-loads for its occupant. Unusually for Soviet programmes provision was made for either a land or sea touchdown with the latter taking place in the Indian Ocean.

But in January 1966, OKB-1 and the entire Soviet programme were dealt a major blow. Sergei Korolev died on the operating table following complications during for what was thought to be routine abdominal surgery. As the Soviet Union mourned, it was up to his deputy Vasiliy Mishin to pick up the pieces and try and push forward with the multiple programmes and problems facing OKB-1 (soon to be renamed TsKBEM in an industry wide re-organisation). Unfortunately it seems that although a talented engineer and Korolev’s protege for many years, Mishin lacked many of his mentor’s abilities regarding the ability to drive projects through innumerable political and engineering obstacles.

Throughout 1966 TsKBEM struggled with a huge workload, with commitments to both manned lunar programmes, planned robotic lunar and planetary explorations and military projects. As the year drew to a close, the first unmanned flight of the 7K Soyuz took place (under the generic designation Kosmos-133) on November 28th. Although this was less than successful both the 7K and L1 projects pushed on into 1967. The first unmanned flight of the L1 took place on March 10th 1967 under the name Kosmos-146. This vehicle was intended as a systems test and no recovery was attempted. A second flight, Kosmos-154 launched on April 8th and successfully reached orbit, but a failure of BLOK D’s ullage motors meant the planned TLI burn was impossible.

Disaster strikes…
Before another L1 test could take place there was the first manned Soyuz flight to attend to and this took place when Soyuz 1 carrying Cosmonaut Vladimir Komarov launched on April 23 1967. Having seen the American Apollo programme dealt a terrible blow earlier in the year when the crew of Apollo 1 were lost during a fire on the launchpad, it seemed that NASA’s misfortune may allow the Soviets back into the race for the Moon.

The launch of Soyuz 2 carrying 3 Cosmonauts was to follow a day later with a rendezvous, docking and transfer of crew all planned for the spectacular joint mission. It had been hoped that in one stroke the programme could catch up with America’s progress during Project Gemini and demonstrate many key techniques required for the L3 lunar landing mission, but tragedy struck. Numerous technical problems including the failed deployment of a solar panel marred Soyuz 1. The launch of Soyuz 2 was scrubbed and Komarov attempted to bring the ailing craft home but during re-entry problems with parachute deployment led to Soyuz 1 impacting the Steppe at high speed instantly killing Komarov.

A hiatus followed as inquiries probed the reason for the disaster and as a result not only the 7K Soyuz programme but also the related L1 and L3 were delayed.

Return to flight
The L1 programme attempted to get back on track during September 1967 with the launch of Zond 1967A. The name Zond (meaning ‘probe’ in Russian) had previously been used for an earlier series of planetary probes and seems to have been applied to the circumlunar programme to conceal the true nature of the flights, but western analysts were quick to determine that from 1967 the series represented a series of unmanned tests for a Soyuz variant. The launch took place on September 27th but unfortunately engine failure in the Proton’s first stage caused the vehicle to be destroyed, although the launch escape system operated as designed and capsule was recovered.

An L1 Complex is prepared for flight [IMG: Wikipedia under CC license]
Zond 1967B followed on November 22nd, but this time a failure in the booster’s second stage caused the booster to be destroyed. The next flight didn’t take place until March 2nd 1968 as Zond 4 thundered into the skies above Baikonur. Rather than wait for a launch window which would allow a circumlunar flight, Zond 4 simply performed a flight out towards an ‘imaginary’ moon to test the craft’s systems at lunar distances. While the flight appears to have met most of its goals, there was a failure during re-entry meaning a ballistic rather than skip profile was followed. As this would have resulted in the capsule landing outside of the designated recovery area, the self-destruct system was utilised and the capsule destroyed. Commenting on the 20G re-entry and subsequent destruction of Zond 4, Senior Cosmonaut Alexei Leonov is said to have wryly commented “We’ll survive that. Only if you don’t blow us up”.

While Zond 4 had provided the beleaguered engineers at TsKBEM some vindication, the relief was to be short lived as the next two flights both failed – Zond 1968A due to second stage failure on April 23rd and Zond 1968B partially exploded on the pad, killing technicians on July 21st. This incident left the crippled vehicle partly suspended by the launch tower and a difficult recovery operation was needed to defuse the situation. By now, the L1 programme was under increasing pressure to produce a successful flight. The high failure rate combined with the tragic death of Yuri Gagarin shortly after the flight of Zond 4 in March 1968 had all sapped morale within TsKBEM. To add to the pressure Apollo was due to return to flight during September 1968 with Apollo 7 and success would surely mean an American circumlunar flight would not be too far away.

Mishin was under increasing political pressure to pursue an aggressive flight schedule with the aim of a crewed flight before the end of 1968, but he stuck to his belief that at least two successful demonstration flights were necessary prior to risking the life of a Cosmonaut. Others within TsKBEM were equally cautious. In his memoir Rockets and People, veteran engineer Boris Chertok comments ”Now, as far as I can remember, and the more I talk to veterans, it seems that we didn’t have a great deal of faith in a piloted L1 flight…If we could fly around the Moon in unpiloted mode and return the spacecraft to the ground at reentry velocity before the Americans, then why send a human being on this risky journey?”.

A UR-500K/L1 Zond complex on its way to the pad [IMG: Wikipedia under CC license]
Zond 5 was launched on September 15th 1968 with a crew of biological specimens including 2 steppe tortoises. This time both the booster and BLOK D worked perfectly and Zond 5 was on its way to the Moon. During the flight there was consternation and excitement in the west as the British Jodrell Bank radio telescope picked up a cosmonaut’s voice coming from the Zond, but these were only recordings to test the communications equipment. Problems occurred with the ship’s orientation during the return journey and once again a ballistic entry occurred, but the re-entry capsule splashed down safely in the Indian Ocean and was recovered soon after by Soviet ships.

Although the flight had been far from perfect it had successfully proved the hardware and the flight profile and thoughts began to turn again to the possibility of beating Apollo around the Moon. Soviet authorities felt sufficiently encouraged to concede that the mission had been a robotic test for a craft capable of carrying a Cosmonaut. Three crews were in the final stages of training for the mission: Leonov & Makarov, Bykovskiy & Rukavisnikov and Popovic & Sevastyanov with Bykovskiy’s crew the favourites to make the initial attempt, but Mishin still needed to replicate Zond 5’s success at least once more before committing to a crewed launch.

The final push
Zond 6 was prepared for the mid-November launch window, but before the flight could occur the launch of Apollo 7 took place on October 11. Discussions within NASA had reached the bold decision to send Apollo 8 around the Moon in December of 1968 if Apollo 7 proved succesful. In a packed Earth orbital shake-down flight, the crew proved the re-designed Apollo CSM was ready and able to undertake a flight of circumlunar duration and so the scene was set for a final showdown.

While the CIA and NASA were well aware of the Zond programme and the possibilities of a manned launch prior to Apollo 8, this was only one of the many contributing factors behind the decision to send Apollo 8 to the Moon, but the preparations for Zond 6 were eyed nervously as the November 10th launch approached. As with the previous flight the booster and TLI stage worked perfectly and Zond 6 carried its biological specimens around the Moon, but during the return journey things went wrong. The capsule began to lose pressure, a situation that would have been fatal for the crew, but other systems seemed to be performing well. The complex skip re-entry was successfully executed and the re-entry apparatus began its descent under parachute.

Unfortunately, the loss of pressure had affected the parachute system and the main chute was cut loose during descent while the craft was still some distance from the ground. The remains of Zond 6 crashed to the ground and with them went the hopes of the Soviet Union putting the first man around the Moon.

December 1968
Aware of the problems with Zond 6, western analysts were nonetheless open to the possibility that the Soviets may take the chance and risk a manned flight in the next launch window. While preparations were underway for Apollo 8’s impending launch there was nothing America could do about the laws of physics that dictated that a December launch window open earlier for the Soviets. While Apollo 8 was due to launch on December 21st, the Soviets would be in a position to launch between the 9th and 14th of December.

In reality though, Mishin wasn’t about to take any such risks with a Cosmonaut’s life, although many within the Cosmonaut corps felt willing to take the risk, even unsuccessfully taking their case to higher authorities.

Apollo 8 launched as planned and carried out a hugely successful flight, not only reaching the Moon, but entering orbit before returning safely – all to the acclaim of a global audience. Man had not only seen the surface of the Moon close-up, but had also seen the fragile Earth suspended in the vastness of space. The fact that Zond 5 had returned similar ‘Earthrise’ pictures earlier in the year seemed unimportant now.

In the aftermath of Apollo 8 the question facing the Soviets was whether to press on with the manned circumlunar programme or to put it to one side and concentrate what energies remained on the N-1/L3 moon landing plan. In January 1969 a series of high level meetings were held involving the senior managers and designers of the Soviet space programme to decide how to respond.

While some were still in favour of continuing with the L1 programme the general consensus was to move towards robotic explorations. Thematically this meant greater support for the robotic lunar landers then under development by the Lavochkin bureau and a re-orientation of future Zond flights towards unmanned scientific missions. Any further plans for manned L1 missions were officially postponed in March 1969. Additional Zonds were flown to use up the hardware already produced, but these continued to be marred by failures both with the launcher and elements of the L1, suggesting the decision not to pursue a manned flight was probably the correct one.


The Earth as photographed by Zond 5 during its circumlunar flight in 1967 [IMG: Wikipedia under CC license]
By 1969 the Soviet space programme was in a state of disarray. What had been a powerful propaganda tool in the early 1960’s now became something of an embarrassment with no obvious response to Apollo. While the N-1/L3 programme forged on in the hope setbacks would delay an American moon landing, there was really little point in pursuing a circumlunar flight that couldn’t even orbit the Moon.

It’s hard not to look at this period without engaging in a hypothetical game of ‘What If?’. Had Korolev lived, could he have steered the L1 programme to a successful conclusion? Had the party continued to support Korolev over Chelomei, could the early success have been maintained? It’s impossible to answer this sort of question with any certainty, but it does seem fair to conclude that some costly mistakes were made.

Chelomei’s rise in the early sixties had the dual effect of allocating scarce resources to projects that never reached fruition while simultaneously depriving OKB-1’s Soyuz and N-1 programmes of the funding they needed to reach their long term goals. While Chelomei was a talented and imaginative engineer, he appeared to lack the ability to execute projects in the way Korolev could. His patronage under Kruschev also led to more projects than OKB-52 could realistically handle during the period. While his LK-1 plan was certainly feasible, it was only really useful as a propaganda tool if it got to the Moon before Apollo, therefore delays could not be tolerated.

On the other hand, had the circumlunar flight been left with OKB-1 in 1964 it seems likely that the 7K-9K-11K plan would have been revised in favour of a more direct approach using Soyuz and the N-II booster. Without the circumlunar flight, there was no pressing need for the N-II and so what would have been a vital opportunity to prove systems for the N-1 was lost putting more pressure on  a deferred all-up flight testing of that booster.

In hindsight an integrated programme treating circumlunar flights as a step on the way to a moon landing would seem to have been the more rational course and may well have created a more capable infrastructure of medium and heavy booster for future endeavours.

With regards to Korolev, his death was a huge blow. In the absence of any single NASA style organisation to oversee all space activities, his managerial abilities had created a political and technical environment for the early successes. Without him that sense of direction was lost and this malaise was only intensified by the subsequent losses of Komarov and the talismanic Gagarin. Much blame is often placed with Mishin for the loss of direction post-1966, but some commentators have suggested that other key figures could have stepped in, but preferred to let Mishin continue as a scapegoat in expectation of eventual failure.

The subsequent denial of their lunar intentions, both with the L1 and L3 plans provided the Soviet leadership with a means to save face, but meant that the many achievements of the engineers and designers who strived to take a Cosmonaut to the Moon were left unrecognised for too long.

For more details on the N-1/L3 Lunar Landing plan Click Here

Sputnik and the Soviet Space Challenge – Asif A. Siddiqi
The Soviet Space Race with Apollo – Asif A. Siddiqi
Soviet and Russian Lunar Exploration – Brian Harvey
False Steps: The Space Race as it might have been – Paul Drye
Red Star in Orbit – James E. Oberg
Two Sides of the Moon – David Scott and Alexei Leonov
Korolev – James Harford
Apollo: The Race to the Moon – Charles Murray, Catherine Bly Cox
Spies and Shuttles: NASA’s Secret Relationships with the DoD and CIA – James E. David
Rockets and People: Volume III Hot Days of the Cold War and Rockets and People: Volume IV the Moon Race – Boris Chertok (Series edited by Asif A. Siddiqi)