The past decade or so has seen a marked increase in interest to reach the Moon for exploration as well as the potential exploitation of its resources. Not only are today’s major space powers involved in this latest push, but most spacefaring nations and many private companies around the globe as well. This is in marked contrast to the situation at the dawn of the Space Age two-thirds of a century ago when the superpowers of the day, the United States and the Soviet Union, were the only players on the stage of lunar exploration and were struggling to beat each other to the Moon. Despite the best efforts of the US, it would be the Soviet Union who would reach the Moon first after a series of frustrating (and at the time, completely secret) failures.
The Beginnings of the Soviet Lunar Program
The launching of the first Sputniks under the direction of Soviet aerospace pioneer, Chief Designer Sergei Korolev of OKB-1 (the Russian acronym for “Experimental Design Bureau 1”), caused such a stir in the West that Soviet Premier Nikita Khrushchev could not help but exploit the propaganda value of Soviet space missions (see “Sputnik: Launch of the Space Age”). But with the successful launching of the first three Sputnik satellites during the first months of the Space Age, all the “easy” space spectaculars had already been achieved. By the beginning of 1958 the Soviet Union’s infant space program had set its sights on the Moon.
Portrait of Chief Designer Sergei Korolev who led the effort at OKB-1 to build the R-7 ICBM and the Soviet Union’s first satellites. (RKK Energia)
Even in the opening months of the Space Age, Soviet engineers and scientists had already spent years studying potential lunar missions. While serious work on Earth satellites was moving forward during the early to mid-1950s, a handful of Soviet theoreticians and designers were quietly making the first tentative steps required to explore the Moon. At this point in time, the most basic questions had to be answered: What sort of missions were needed? What are the velocity requirements for these missions? How long would these missions take?
Over time a number of missions types were identified and investigated including lunar orbiters and “cycling stations” that would orbit continuously between the Earth and Moon. By far the most advanced concept publicly announced by the Soviet media was revealed on April 26, 1955 by Radio Moscow and later detailed in a Russian-language magazine article by Yuri S. Khlebtsecich the following November. Plans were outlined for a radio-controlled lunar “tankette” that would be launched by a large, multi-stage rocket. This remote-controlled rover could make observations over large stretches of the lunar surface and report its findings back to Earth. However, this sort of mission was well over a decade away.
Korolev (left) with Igor Kurchatov (the “father” of the Soviet H-bomb) and Mstislav Keldysh in 1956. (Keldysh Museum)
Lunar missions were always part of Korolev’s space plans. When his satellite program was approved by the Soviet government in the beginning of 1956, work on more advanced missions also began to move forward not only at Korolev’s OKB-1 but at other institutions as well. Among these was a group at MIAN (Mathematical Institute of the Academy of Sciences) under Korolev’s friend and ally, Academician Mstislav V. Keldysh, who began making detailed calculations of over 600 trajectories to define precisely the requirements for various lunar missions.
Based on scientific objectives and the projected availability of technology, a three-step strategy for long-term lunar exploration was eventually devised. The first step, which could make use of current or soon to be available technology, consisted of a series of flyby, impact, or hard landing missions. With a few more years of development, the second step would become possible. In this phase, payloads would be delivered to the lunar surface and into orbit. The last phase, which would require many more years of work, involved delivering automated probes to the Moon and returning a payload of surface samples or exposed film back to Earth.
Tikhonravov (left) and Korolev in 1947 at a celebration of the 90th anniversary of the birth of Tsiolkovsky. Tikhonravov led the team at OKB-1 to develop the first Soviet lunar probes. (TASS)
In April of 1957, the project department for the development of spacecraft at OKB-1 under Mikhail Tikhonravov submitted a report on the exploration of the Moon and the launching of manned satellites. The one point that was made clear immediately was the need to build a launch vehicle more capable than the existing derivatives of the two-stage R-7 ICBM (known internally as the 8K71 and as the SS-6 or Sapwood in the West) that would launch the first satellites. As early as 1955, Korolev had anticipated this need and considered attaching a third stage on top of the basic 8K71 to greatly improve its performance. By the summer of 1957 development of this stage, called Blok E, had begun.
This cutaway drawing shows the details of the original R-7 or 8K71 ICBM which would be used as the basis of the launch vehicle for the first Soviet lunar probes. Click on image to enlarge. (RKK Energia)
The Gas Dynamics Laboratory at OKB-456 under the direction of Valentin Glushko was given the assignment of developing an engine, designated RD-109, for the Blok E. Glushko and his engineers felt that a fuel other than kerosene, which the 8K71 used, should be employed. Ultimately, they chose UDMH (unsymmetrical dimethyl hydrazine). Since there was little experience in developing a large engine to burn such an exotic (not to mention corrosive and toxic) fuel, Korolev felt that developing the RD-109 would take much longer than Glushko expected. In order to avoid delays and despite Glushko’s protests, Korolev started parallel development of his own engine, the RO-5, at OKB-1 that burned the more conventional fuel, kerosene. Based on the S1.25800 steering engines OKB-1 developed for use with the RD-107 engine that powered the 8K71, the RO-5 would only be half as powerful as Glushko’s RD-109. Despite its smaller size, the RO-5 still provided the performance needed to reach the Moon.
A portrait of Valentin Glushko who headed the Gas Dynamics Laboratory at OKB-456 which developed many of the rocket engines used on early Soviet missiles and launch vehicles.
The Soviet Program Moves Forward
With the successful launch of the first Sputnik and the furor that ensued, Khrushchev bypassed the existing chain of command and quickly conferred directly with Korolev to determine what other space spectaculars were possible. With Khrushchev’s backing, Korolev’s dreams for space exploration were to advance much more quickly than he could have ever imagined. The launching of additional satellites, such as Objects PS-2 and D (which became Sputnik 2 and 3, respectively – see “Sputnik 2: The First Animal in Orbit” and “Sputnik 3: The First Orbiting Geophysical Laboratory”), was immediately approved. Resources were also made available for the development of manned spacecraft as well as probes to the Moon and planets. Upon returning from his meeting with the Soviet leader, Korolev directed Tikhonravov and his project department to begin work on vehicles to explore the Moon. Tikhonravov delegated the task of designing and building the first Soviet lunar probes to a team of young engineers and scientists at OKB-1 affectionately known as the “Lunatics”.
Diagram showing the 8K72 launch vehicle equipped with a Blok E stage on the right. Click on image to enlarge. (RKK Energia)
By December of 1957 the outline for the two lunar launch vehicles based on the 8K71 ICBM, had been worked out. Both launch vehicles would use a stripped-down version of the R-7 designated 8K71/III. The first rocket, the 8K72 would use a Blok E third stage built around Korolev’s RO-5 engine which by this time was being jointly developed with OKB-154 under Semyin Kosberg. This engine produced 49.9 kilonewtons of thrust for 450 seconds by burning about 6.93 metric tons of kerosene and LOX (liquid oxygen) held in separate toroidal tanks. This Blok E third stage, called 8K72E, was 2.66 meters in diameter and stood 5.0 meters tall with its conical nose shroud in place. It was attached to the top of the 8K71/III “basic packet” by a simple open truss which allowed the exhaust of the engine to escape as it ignited. Depending on the mission profile, the 8K72 could send up to about 400 kilograms of useful payload on a direct ascent trajectory to the Moon. This would be the most powerful launch vehicle of its day capable of lifting over an order of magnitude more payload to the Moon than any American rocket soon to be available (see “The Largest Launch Vehicles in Service – 1957 to the Present”).
A cutaway diagram showing the 8K72 Blok E stage with an E-1 lunar probe. Click on image to enlarge. (RKK Energia)
The second lunar launch vehicle, called the 8K73, would have a Blok E third stage incorporating the much larger RD-109 being developed by Glushko’s OKB-456. The RD-109 produced 101.6 kilonewtons of thrust and would consume 8.05 metric tons of UDMH and LOX during a 330 second burn. Despite the different engine, the 8K73E stage’s construction was very similar to the 8K72E. The 8K73E stage had the same diameter as the 8K72E but was 1.1 meters taller to accommodate the larger propellant load. With 16% more propellant, an engine that was 2% more efficient, and a 26% shorter burn time which cut gravity losses during a direct ascent towards the Moon, the 8K73E was better than the 8K72E for missions to the Moon and beyond with a lunar payload capability of over 550 kilograms.
In December of 1957 Korolev formally submitted his lunar plans for approval. The primary objective of the first mission would be to impact the Moon. In order to determine what instrumentation should be carried on this and subsequent lunar missions, Korolev met with Soviet astronomers to get their input. Given the secrecy that enveloped the development of Soviet space hardware and the fact the Space Age had just begun, these astronomers were amazed to discover that a flight to the Moon was not only possible but almost at hand. Eventually it was decided that the first lunar probes would measure magnetic fields, assess the radiation environment, and determine the density of micrometeoroids during its flight. These missions would only require a simple spheroidal probe about 1.2 meters in diameter with a mass of about 170 kilograms and no attitude control that could be quickly developed.
This Moon probe, designated E-1 (“E” being the next letter in the Cyrillic alphabet after the Sputnik 3 Object “D”), would use the 8K72 which was scheduled to make its first test flight in June or July of 1958. In order to maximize the payload, the launch was restricted to a two to three-minute window during a three-day period when the Moon was either about 10 or 23 days old, depending on the season. A short flight time of about 38 hours would ensure that the probe would be visible from the Soviet Union during its lunar encounter. This type of fast trajectory also had the benefit of minimizing the effects of aiming and final velocity errors. To help reduce the latter, the 8K72E stage would use radio commands to shut down its RO-5 engine when the proper velocity had been achieved.
Photograph of the Soviet E-1 lunar probe built by OKB-1. (RKK Energia)
In the original proposal, post-launch tracking of the receding lunar probe would be aided by either an inflatable 30-meter in diameter aluminized balloon or, as proposed by Soviet astronomer Professor Iosef Shklovsky, an artificial comet of lithium or sodium vapor released from the spent Blok E stage. Depending on the available payload margin of the 8K72, additional engineering and scientific equipment could be carried by the Blok E to supplement investigations by the E-1 probe. Korolev scheduled this flight to take place around August or September of 1958.
The next set of missions would use more advanced, three-axis stabilized probes designated E-2 and E-3. These probes, with a mass of about 280 kilograms each, would image the unseen far side of the Moon using an automated photographic system. In addition to this primary instrument, these probes could carry other sensors to continue investigations of the cislunar environment. Because of the alignments of the Earth, Moon, and Sun these missions required, the E-2 and E-3 could only be launched in October-November or April-May. The development of these more sophisticated probes, which was made the responsibility of Yuri Mozzhorin, would require more time than the E-1. If all went according to schedule, the 8K73 would be available to launch the first of these probes in October or November of 1958.
One last lunar “probe” that was considered at this time was the E-4. Its mission would be to set off a nuclear explosion upon impact with the lunar surface that could be viewed from the Earth leaving no doubt that a Soviet probe had reached the Moon. Weighing in at about 400 kilograms, the E-4 would require the lifting capability of the 8K73. While an interesting publicity stunt, Korolev was not enthusiastic about beginning an era of lunar exploration with the nuclear bombardment of the Moon. There were also genuine concerns about the visibility of a nuclear detonation on the airless Moon. Ultimately the E-4 was cancelled. After these lunar missions Korolev intended to move on and use the 8K73 to launch the first probe to Venus, designated V1, in June of 1959 followed by launches to Mars the following year (see “The First Mars Mission Attempts” and “Venera 1: The First Venus Mission Attempt”). Korolev’s aggressive plans for lunar exploration were approved by the Soviet government on March 28, 1958.
A Bad Start
Just as Korolev had feared, the development of the RD-109 engine dragged on much longer than planned. This delay along with problems with the R-7 and its engines uncovered during development flights and bench tests threatened to scuttle Korolev’s original optimistic lunar exploration schedule. But by May 1958 the first 8K71/III, serial number B1-14, had been modified in the shops at OKB-1 outside of Moscow and in early June it was delivered to the NIIP-5 range in Kazakhstan (Scientific Research Test Range No. 5 – today known as the Baikonur Cosmodrome). Because of the lagging development of the RO-5, an engine-less Blok E equipped only with telemetry and control systems would be carried on this suborbital test flight to verify the overall design and structural integrity of the new rocket. The first 8K71/III finally lifted off on July 10, 1958. While there are conflicting accounts of what exactly happened, all the sources agree that the test was unsuccessful.
In the meantime, preparations to launch the first E-1 probe early on August 18 were falling behind. The pressure to get the first E-1 probe to the Moon was all the more intense because the US was planning to launch its first lunar probe as part of the USAF Project Able-1. Frustrated by a series of malfunctions on the pad with 8K72 serial number B1-3, Korolev finally called off the launch after hearing of the USAF Thor-Able 1 failure (see “USAF Project Able-1: The First Attempt to Reach the Moon”). The uncooperative 8K72 rocket was removed from the pad and returned to the MIK assembly building in hopes of making another launch attempt the following month.
Pioneer_launch_failure.jpg The launch of Thor 127 carrying the Project Able-1 upper stages and payload on August 17, 1958 (left) followed 74 seconds later by its destruction following a turbopump failure (right). (USAF)
For the next launch window in September, Korolev’s team would have the stage to themselves as the USAF tracked down the cause of the Project Able-1 launch failure. In the meantime, a new name was officially adopted by the USAF for this series of flights – Pioneer. The first unsuccessful launch attempt was retroactively designated “Pioneer 0” with the next mission scheduled for October to be called “Pioneer 1”.
On September 23, 1958, the Soviet 8K72 B1-3 was back on its pad ready to try for the Moon again. The unproven rocket smoothly lifted off at 12:03:23 Moscow Time (09:03:23 GMT) during its brief launch window and accelerated towards its target. But as the propellant tanks of the core and strap-on boosters emptied, longitudinal resonance vibrations (an effect called “pogo”) appeared. Pogo had been encountered in some earlier flights of the R-7 and Korolev’s engineers thought they had understood and corrected for its cause. The reappearance of this problem would finally doom the flight 93 seconds after launch when the strap-on boosters broke loose. The now free flying collection of uncontrolled rockets with the E-1 No. 1 probe still attached tumbled to the ground and exploded on impact. The Soviet’s first attempt to reach the Moon ended as ingloriously as the American’s. But unlike the American attempt, this failure was kept quiet firmly establishing the Soviet government’s policy of keeping launch failures secret.
The Race Heats Up
Another 8K72, serial number B1-4, was hastily modified by Korolev’s engineers for another clandestine launch attempt the next month. As in August, Korolev would have to race against the Americans who were preparing another Thor-Able to launch a 38.3-kilogram Pioneer probe towards lunar orbit. This time, the American mission would be sponsored by their new civilian space agency, NASA. Word arrived about the successful launch of Pioneer 1 at 09:42:13 GMT on October 11 as Korolev and his team pushed hard to make their launch window during the early local morning of October 12. While Pioneer 1 was the first up, the faster trajectory of Korolev’s E-1 No. 2 probe would allow it to reach the Moon several hours before the American probe giving the Soviet Union another space first. A true race to the Moon like never seen before or since was on.
The launch of Pioneer 1 from Pad 17A at Cape Canaveral on October 11, 1958. (USAF)
After a night of hectic preparations, the second 8K72 lifted off its launch pad at 02:41:58 Moscow Time (23:41:58 GMT on October 11) to chase after its American competitor. But despite the best efforts of Korolev and his team, the pogo effect that destroyed the first 8K72 launch vehicle reappeared in the new rocket as it climbed towards space. After a flight of 104 seconds, 8K72 B1-4 finally disintegrated under the stress. With this latest failure, future launch attempts to the Moon using the 8K72 were put on hold until the cause of the ongoing problem could be ascertained and a fix implemented.
Fortunately for Korolev and his team, it was soon discovered that Pioneer 1 was not headed for the Moon after all. Initial tracking of the receding Pioneer 1 showed that the spacecraft was travelling slower than required. In the hours following launch, continued tracking made it apparent that the probe was also off course (see “Pioneer 1 – NASA’s First Space Mission”).
With this last of the three planned Pioneer orbiter flights (unsuccessfully) launched in November 1958, NASA’s lunar hopes turned to the pair of smaller Pioneer flyby probes which would be ready to launch in December. Fortunately for Korolev and his team, the different trajectory requirements of this Pioneer mission dictated a launch window that opened two days after the next Soviet E-1 launch attempt. In the meantime, the Soviet commission charged with finding the reason for the first two 8K72 launch failures were able to trace the source of the problem. While the longitudinal vibrations during powered ascent called “pogo” had been largely eliminated from the two-stage R-7 variants, it was discovered that the addition of the new Blok E third stage raised the rocket’s center of gravity in such a way to make the problem reappear. A simple baffle was introduced in the boosters’ oxidizer pipeline to eliminate the effect and Korolev’s team was ready to try for the Moon again.
Originally limited to an estimated mass of 170 kilograms, the E-1 probe nicknamed “Lunik” by its builders at OKB-1 (a moniker that was later applied by the West to all early Soviet lunar probes) could now afford to gain some weight due to enhancements in the performance of the 8K72 launch vehicle. The E-1 was a 1.2 meter in diameter, polished aluminum-alloy sphere with a pressurized interior designed to maintain a temperature of 20° C. It contained all the sensitive electronic equipment including the transmitter, instruments, and batteries to power it all. Data would be transmitted at preprogrammed intervals in order to extend the battery life to about 60 hours.
Soviet diagram showing the major components of the Soviet E-1 lunar probe: 1) Magnetometer, 2) VHF antenna, 3) micrometeoroid counter, 4) batteries & electronics, 5) ventilator fan, 6) spacecraft shell, 7) ion traps and 8) HF ribbon antennas. Click on image to enlarge.
Its suite of scientific instruments included a magnetometer mounted on a meter-long boom, a piezoelectric micrometeorite detector and devices to detect and characterize various types of cosmic radiation including versions of an instrument which had been flown earlier in Earth orbit on Sputnik 3 launched in May of 1958. The E-1 also carried a pair of spheres, one 15 and the other 9 centimeters in diameter, composed of small medallions bearing the coat of arms of the Soviet Union. The spheres were designed to shatter on impact spreading the medallions across the impact site to commemorate the historical achievement. The fattened E-1 weighed in at about 192 kilograms.
The spheres composed of commemorative pennants carried by the E-1 missions. (RKK Energia)
Instead of wasting the unused payload capability of the 8K72, it was decided that the Blok E escape stage would carry another 169 kilograms of scientific and radio-equipment to supplement Lunik’s measurements. Included was a package to vaporize one kilogram of sodium to produce a short-lived artificial comet on the way to the Moon. Originally suggested by Soviet astronomer Iosef Shklovsky, this experiment would yield interesting insights into Earth’s outer magnetosphere and serve as a tracking aid.
The next 8K72, serial number B1-5, lifted off carrying E-1 No. 3 at 21:18:44 Moscow Time (18:18:44 GMT) on December 4, 1958 from Area 1 of NIIP-5 test range in Soviet Kazakhstan. Unlike the first two flight attempts, this time the rocket flew flawlessly through to the dropping of its four boosters. The pogo problem had finally been solved. But 245 seconds after launch as the core was still firing, thrust in its RD-108 engine dropped to 70% and then quit altogether. A failure in the engine’s turbopump had brought the Soviet’s third attempt to reach the Moon to a premature end.
While rumors of this and other launch failures circulated for years, details would remain secret until the fall of the Soviet Union 34 years later. In the meantime, engineers at OKB-1 would have to prepare another E-1 probe and 8K72 launch vehicle for a fourth attempt near the New Year. But before then, NASA’s next Pioneer probe had its shot to reach the Moon. Unfortunately for NASA, the Pioneer 3 launched on December 6 fell well short of the Moon reaching a peak altitude of only 102,300 kilometers before it arced back to Earth and a destructive reentry (see “Pioneer 3: JPL’s First Moonshot Attempt”). The Soviets would get one more try at reaching the Moon first.
Success… Sort of
As the end of December approached, Korolev and his team pushed hard to make their next launch attempt to the Moon on New Year’s Day 1959. Preparations proved difficult as the temperatures on the snow-covered steppes of Soviet Kazakhstan dropped to -30° C and the launch crews were pushed almost to exhaustion. As the world rang in 1959, 8K72 serial number B1-5 was finally rolled out onto its pad at Area 1 at the NIIP-5 test range. Under the rocket’s nose was 361.3 kilograms of payload including the E-1 No. 4 Lunik probe. At 19:41:21 Moscow Time (16:41:21 GMT) on January 2, the giant 8K72 Moon rocket lifted off in the Soviets’ fourth attempt to reach the Moon. Unlike the previous flights, this time the first two stages did not suffer any major malfunctions allowing the Blok E stage to push its cargo towards the Moon.
The launch of a Mechta (later known as Luna 1) on 8K72 B1-5 on January 2, 1959. (RKK Energia)
Initial tracking of the probe and its escape stage indicated that everything worked and that escape velocity had been achieved for the first time leading to the Soviet designation of “the First Cosmic Ship”. Lunik, now officially named “Mechta” (Russian for “Dream” but, starting in 1963, this mission was retroactively designated “Luna 1”), was on its way to the Moon. Eight hours after launch at an altitude of about 120,000 kilometers over the Indian Ocean, the spent Blok E released a fluorescent cloud of sodium vapor that expanded to 650 kilometers across in five minutes before fading from sight. Visible from most of the Eastern Hemisphere, this spectacle was proof that the Soviets were on the way to the Moon.
Despite the initial flurry of excitement, careful tracking indicated that the Blok E escape stage had been misprogrammed imparting slightly too much speed causing the probe to miss the Moon. On January 4 some 34 hours after launch, Luna 1 passed within 6,000 kilometers of the Moon. Even though it failed to hit the Moon as intended, the probe’s instruments worked perfectly and returned useful data on the cis-lunar environment for the first time. The Soviet press, however, trumpeted the flight as a total success with the first close pass by the Moon.
Soviet diagram of the solar orbit of Luna 1: 1) The Earth, 2) Earth’s orbit, 3) Mars, 4) Mars’ orbit, 5) trajectory of Luna 1, 6) perihelion (0.978 AU) and 7) aphelion (1.318 AU).
Luna 1 was tracked until January 5, 1959 some 62 hours after its launch. At a range of about 597,000 kilometers, the probe’s batteries finally gave out ending a less than successful but very fruitful mission. The now silent First Cosmic Ship continued on in a 0.978 by 1.318 AU (146.4 by 197.2 million kilometer) solar orbit with a period of 449.5 days to become the first “manmade planet” to orbit the Sun (although aluminum pellets launched from an American Aerobee sounding rocket in October 1957 might be claimed as being the first objects launched into solar orbit – see “Fritz Zwicky’s Solar Orbiting Pellets”). The partial success of Luna’s mission provided enough fuel for the Soviet propaganda machine to allow Korolev the time he needed to analyze the mission’s results and plan the next step. In the meantime, another apparent space first for the Soviet Union along with the immense size of the payload weighed heavily on an increasingly nervous West.
Related Reading
“Failure to Launch: The First Moon Race 1958-60”, Drew Ex Machina, June 2, 2023 [Post]
“The First Race to the Moon: Getting Off the Ground”, Drew Ex Machina, November 8, 2018 [Post]
“The First Race to the Moon: Reaching Our Neighbor”, Drew Ex Machina, September 14, 2019 [Post]
General References
Brian Harvey, Soviet and Russian Lunar Exploration, Springer-Praxis, 2007
Wesley T. Huntress and Mikhail Ya. Marov, Soviet Robots in the Solar System: Mission Technologies and Discoveries, Springer-Praxis, 2011
Nicholas Johnson, Handbook of Soviet Lunar and Planetary Exploration, Univelt, 1979
Ari Shternfeld, Soviet Space Science, Basic Books, 1959
Asif Siddiqi, “First to the Moon”, Journal of the British Interplanetary Society, Vol. 51, No. 6, pp. 231-238, June 1998
Timothy Varfolomeyev, “Soviet Rocketry that Conquered Space Part 2: Space Rockets for Lunar Probes”, Spaceflight, Vol. 38, No. 2, pp. 49-52, February 1996
Timothy Varfolomeyev, “Soviet Rocketry that Conquered Space Part 3: Lunar Launchings for Impact and Photography”, Spaceflight, Vol. 38, No. 6, pp. 206-208, June 1996