Category Soviet and Russian Lunar Exploration

The Ye-8 series included two orbiters, Ye-8LS, both being launched successfully. They flew the last of the trio of rovers of orbiters and rovers, although it had originally been intended they go first. Their role was to:

• Take photographs of points of interest so as to identify landing sites for later sample return, rover and manned missions.

• Study mascons, magnetic fields, the composition of lunar rocks, meteorites and cislunar space.

New cameras were developed for the series by Arnold Selivanov. Essentially, he adapted the optical-mechanical camera of Luna 9 and 13 as an orbital panoramic camera in such a way as to make 180° long panoramic sweeps extending to the edge of the moon. The images would be developed on board, scanned at 4 lines/sec and relayed back to Earth. These are called optical-mechanical linear cameras and can be used from moving spacecraft.

Warning of a new moon probe first appeared in January 1971 when predictions of ‘low-flying artificial satellites’ were made that would fly ‘fairly soon’. Sure enough, Luna 19 was launched on 28th September 1971 and entered circular lunar orbit of 140 km at 40°, 2 hr 01 min, on 3rd October. Two sets of details were published for the

first day of operation, indicating either a tweaking of the orbit or a refinement of the earlier figures. Three days later, it settled into steady operational orbit of 127 x 135km, 2hr 01 min, 40°. It is more than likely that Luna 19 kept the large tanks used for orbital insertion and continued to use them for manoeuvres, rather than drop them soon after arrival in lunar orbit. The mission was publicized through periodic reports in Pravda and Izvestia. Although at least five full panoramas were assembled, only one section of one was published, along with an illustration showing the probe being loaded onto its Proton carrier rocket, but the detail is poor.

The mission lasted till 3rd October 1972 and 1,000 communication sessions were held. Luna 19 reported back on magnetic fields, mascons, the lunar gravity field, meteoroids and sent back televised pictures of an area 30°S to 60°S and 20°E to 30°E, the quality of publication much improved compared with Luna 12 in 1966. In February 1972, it swept over the Torrid Gulf near the crater Eratosthenes (11°W, 15°N) and filmed rock-strewn plains above which reared a volcanic-like summit. In order to take such pictures it had dropped into a new, lower orbit of 77 x 385 km, 131 min. Another landing area surveyed was around craters Godin and Agrippa at 10°E, 3°N. Some science reports were issued, noting how Luna 19 had measured solar flares and plasma, mascons, the lunar surface and the composition of its soil. The strength of the magnetic field on the nearside and farside of the moon was compared. Radiation levels were measured, especially their rise and fall during solar flares. Ten solar flares were detected. Some cislunar plasma was detected, but the outcome of this experiment was unclear. An altimeter called Vega was carried to measure the precise distance of the probe to the moon (important during its low perilunes). A gamma ray spectrometer took broad measurements of the composition of the lunar surface. A radio occultation experiment was carried out in May 1972 and this found charged particles about 10 km over the moon. The magnetometer measured magnetic fields as the moon moved in and out of the Earth’s long magnetic tail. The mission lasted 4,000 orbits.

It was a full year before the next orbiting moon probe, Luna 22, took off on 2nd June 1974. The Luna 22 launch came at an important international moment, for the first Soviet-American conference on lunar exploration took place that month, June 1974. Together, the scientists were able to agree on the approximate date of the moon (4bn years), the nature of its crust (thick), the processes that had shaped it and that the moon shared a broadly similar formation to the Earth.

Ground observatories tracked Luna 22 as far as 250,000 km out. Luna 22 entered almost circular moon orbit at 219 x 221km, 2 hr 10 min, 19.6° four days later. A week later, it swooped down to 25 x 244 km for special photography for four days, before going back up again to 181 x 299 km. Over the next year, Luna 22 several times altered its orbit, displaying both versatility and reliability. In November 1974, coinciding with the arrival in orbit of Luna 23, it operated in an eccentric orbit of 171 x 1,437km out, 3 hr 12 min, then raising its perilune to 200 km and making a minor plane change to 21°. Then, in August 1975 it dipped to a mere 30 km over the surface for a week, going out farther to 1,578 km, before returning to a regular orbit of 96 x 1,286 km out when its mission ended in November 1975.

Lunar orbit photography was done both from altitude and at low points, the latter presumably to search for landing sites, but no details were ever given of the sites surveyed and the following two Lunas (23 and 24) were both aimed at the Luna 15 sites which, presumably, had been mapped before 1969. There were two extended periods in which no manoeuvres were made, presumably so as to give time to measure changes to its path arising from distortions in the moon’s gravitational field.

Few scientific results were released from the mission, although they could have been substantial, as evidenced by the heavy radio traffic to and from the probe over the 18 months of its operation. These results could have covered the surface composition, topography and micometeoroid impacts, which were much fewer in the higher orbit. Lunar topography was mapped carefully through the use of an altimeter and a gamma ray spectrometer analyzed the composition of the surface [12]. Science reports indicated that Luna 22 studied the moon’s gravitational field, micrometeorites (23 impacts recorded) and solar plasma. The probe indicated that a sheath of ionized gas forms 8 km over the lunar surface during sunlight. Eight photographs eventually reached the NASA archives in the 1990s. Ten full panoramas were reportedly assembled.

140 x 148 km, 2hr 04min, 40.58°

140 km circular, 2 hr 01 min, 40.58°

127 x 135km

77 x 385km, 2hr 11 min

127 x 135 km

77 x 385km, 2hr 11 min

219 x 221km, 2 hr 10 min, 19°

25 x 244km for four days 181 x 299 km

171 x 1,437km, 3hr 12min, 19.55°

200 x 1,409 km, 3hr 12 min, plane change to 21° 30 x 1,578 km

Orbit raised to 96 x 1,286 km, 21°

The orbital paths of the two missions show similarities and differences. Having adjusted its original insertion orbit, Luna 19 operated for the first portion of its mission from a 127 x 135-km near-circular orbit (October-November). At the end of November, it dropped its perilune to 77 km for three days of photographic observa­tions, before coming back to the circular orbit. In February, Luna 19 went back to its lower perilune, where it apparently stayed. Luna 22, by contrast, followed three sets of orbits. Its operating orbit was around 200 km, dropping twice for photographic surveys for periods of less than a week, in late June 1974 and late August 1975. The perilunes were on both occasions much lower than those of Luna 19, this time descending to 25-30 km. In addition, Luna 22 also flew, twice, into an eccentric orbit, out as far as 1,578 km. The precise rationale for these manoeuvres has never been explained.

Orbiting the moon was as essential to a manned mission as a soft-landing. Good photographs were essential to determine landing sites and it was important to learn as much as possible about the lunar orbit environment to ensure there were no nasty surprises (there were).

The Soviet lunar orbiter programme was commissioned by OKB-1 at the same time as the Ye-6 programme. Called the Ye-7 programme, it made very slow progress in comparison. Two partially completed Ye-7 models were turned over by OKB-1 to OKB Lavochkin in summer 1965 during the move between the design bureaux. After the success of Luna 9, attention focused on the lunar-orbiting missions.

Although the Ye-7 photographic equipment was not ready, Russia still wanted to achieve a lunar orbit before the Americans did so with their upcoming lunar orbiter. There was also political pressure to mark the 23rd Communist Party Congress, opening at the end of March 1966 and the first congress of new Soviet leader Leonid Brezhnev. Georgi Babakin and Mstislav Keldysh proposed that the Ye-6 bus be used to fly a lunar orbit mission in time for the congress.

This hastily conceived lunar orbiter was called the Ye-6S. It used the Ye-6 bus, to which was attached not the normal lander, but a pressurized 245 kg cabin that would serve as a lunar orbiter. It is more than likely that the cabin was taken from what would have been an Earth-orbiting satellite in the Cosmos series. Its shape strongly suggests that it may have been one of the Cosmos series built by Mikhail Yangel’s design bureau in Dnepropetrovsk. It was equipped with seven scientific instruments originally planned for the Ye-7, including a magnetometer on a long boom. From the ground, scientists would also measure gases in the lunar environment by examining signal strengths as the probe appeared and reappeared behind the lunar limb, and watch for changes in the orbit due to the lunar gravitational field. Lunar orbit insertion would be performed by the Ye-6 bus. Instead of a 46 sec burn for soft – landing, a much smaller burn was required for orbit insertion. Once in orbit, the pressurized Cosmos cabin would separate for an independent mission.

The first Ye-6S was launched on 1st March 1966. The upper-stage problems reasserted themselves and block L failed to fire the probe – renamed Cosmos 111 — out of Earth orbit. The second Ye-6S eventually got away on 31st March 1966. No sooner was it streaking towards the moon than it was announced that it was directed towards an entirely new objective — lunar orbit. Eight thousand kilometers from the moon, Luna 10 was turned around in its path and its rockets blazed briefly but effectively. They knocked 0.64km/sec off its speed, just enough to let it be captured by the moon’s gravity field. The boiler-shaped instrument cabin separated on schedule 20 sec later. Luna 10 was pulled into an orbit of 349 by 1,015 km, 71.9°, 2 hr 58 min and became the first spacecraft to orbit the moon.

But, first things first, Luna 10 celebrated the latest Russian achievement in style. Celestial mechanics meant that Luna 10 would enter the first of its lunar orbits just as the Communist Party was assembling in Moscow for its morning congress session. As it rounded the eastern edge of the moon, Luna 10’s transmitter went full on and relayed the bars of the Internationale — in turn, broadcast live by loudspeaker direct to the party congress over the static of deep space. It was a triumphant moment and the 5,000 delegates had good reason to stand and cheer wildly. Thirty years later, it was learned that the ‘live’ broadcast was actually a prerecording taken from Luna 10 earlier in the mission. The radio engineers did not trust the live broadcast to work, but, as they later admitted, playing tricks on the Central Committee was a dangerous game and the truth could only be safely revealed in the 1990s when the Central Committee itself was no more.

Luna 10’s mission lasted way into the summer and did not end till 30th May after 56 days, 460 lunar revolutions and 219 communication sessions. Data were trans­mitted on 183 MHz aerials and also on 922 MHz aerials. A stream of data was sent back by its magnetometer, gamma ray spectrometer, infrared radiometer, cosmic ray detector and meteoroid counter. These found a very weak magnetic field around the moon, 0.001% that of Earth (probably a distortion of the interplanetary magnetic field); no lunar magnetic poles; cosmic radiation at 5 particles/cm2/sec; 198 meteoroid impacts, more in lunar orbit than in the flight to the moon; no gaseous atmosphere; and that there were anomalous zones of mass concentrations below the lunar surface disturbing the lunar orbit (mascons). Using its gamma ray spectrometer, Luna 10 began the first initial survey of the chemistry of the moon, enabling a preliminary map to be compiled. Lunar rocks gave a composition signature broadly similar to basalt, but other important clues to its composition were picked out. The gamma ray spec­trometer was used to measure the level of uranium, thorium and potassium in lunar rock. There were significant variations in radiation levels on the moon, being high in

the Sea of Clouds, for example. Luna 10’s magnetometer was put on the end of a 1.5 m boom and took measurements every 128 sec for two months. Designer Shmaia Dolginov – who had built the original magnetometer on the First Cosmic Ship – was able to refine the range to between —50 and +50 gammas.

Luna 10’s final orbit, as measured on 31st May, was 378-985 km, 72.2° – whether the changes were due to mascons or reflect more accurate measurement of the original orbit is not certain. Despite its hasty assembly, the Dnepropetrovsk Cosmos mission had presented a significant haul of science, significantly advancing the knowledge of the moon in only a couple of months.

Luna 10 instruments

Meteorite particle recorder. Gamma spectrometer. Magnetometer with three channels. Solar plasma experiment.

Infrared recorder.

Radiation detector.

Charged particle detector.

The discoveries of Luna 10

Weak magnetic field around the moon, 0.001%.

No lunar magnetic poles.

Cosmic radiation in lunar orbit.

Meteoroid impacts, more in lunar orbit than in the flight to the moon. No gaseous atmosphere.

Mascons.

Basaltic surface composition.

First mission: Alexei Leonov, Oleg Makarov (backup: Anatoli Kuklin).

Second mission: Valeri Bykovsky, Nikolai Rukhavishnikov (backup: Pytor

Klimuk).

Third mission: Pavel Popovich, Vitaly Sevastianov (backup: Valeri Voloshin).

Not allocated: Anatoli Voronov, Yuri Artyukin, Valentin Yershov.

It is worth stressing that these selections were never absolutely final. Soviet mission assignments were frequently changed, often up till a short period before take-off, an event not unknown in the United States (e. g., Apollo 13). Nevertheless, they indicate the broad intentions which, all things being equal, would probably have happened. What was the decisive factor in the around-the-moon selection? It seems that the first two around-the-moon crews were selected for the around-the-moon flight on the basis that they would also constitute the first two landing flights. This would give them a flight to the moon and back before they went for the landing mission. This would have been like selecting Neil Armstrong and Buzz Aldrin for Apollo 11 and then deciding to send them, much earlier, on the Apollo 8 mission to the moon. Indeed, there was some discussion that the Apollo 8 crew of Borman, Lovell and Anders should, because of their around-the-moon experience, go for the moon-landing mission as well. In the event, the Americans chose, for the moon landing, men who had not flown to the moon before. The interchangeability of the Soviet around-the-moon crews with the landing crews is also reflected in the allocation to the group of mathematician scientist Valentin Yershov, one of the designers of the Zond navigation system, but whose priceless presence was also available to the moon-landing group.

Even though Apollo 8 had flown around the moon in December 1968, the L-1 programme was not abandoned. There were several reasons. The hardware had been built or was still in construction. So much investment had gone into the programme that it was felt better to test out the technical concepts involved than write them off altogether and deny oneself the benefits of the design work. If these tests went well, a manned moon circumlunar mission could still be kept open as an option. Indeed, with some of the political pressure lifted, designers looked forward to testing their equip­ment without the enforced haste required by American deadlines. There was also an official problem, bizarre to outsiders, which was that the Soviet government lacked a mechanism to stop the moon programme. At governmental level, no one was yet prepared to admit failure or to take responsibility for what had gone wrong [10]. The resolutions of August 1964 and February 1967 remained in effect, unrepealed. According to Alexei Leonov, the government decided that if the next Zond succeeded, then the following one would be a manned flight, even after Apollo 8.

A new Zond was readied in January and left the pad on 20th January 1969. It is unclear what profile it would have flown, for it was outside the normal launch window. The cabin used was the one salvaged from the April 1968 failure [11]. The second stage shut down 25 sec early at 313 sec, but the other second-stage engines completed the burn. During third-stage firing, the fuel pipeline broke down and the main engine switched off at 500 sec, triggering a full abort. The emergency system lifted the Zond cabin to safety, and it was later retrieved from a deep valley near the Mongolian border. As we know, the period January to July 1969 lacked good launch-and-return windows for Zond missions around the moon, so any missions would have to be performed either under less than ideal tracking, transit or lighting conditions, or would have to be fired at a simulated moon, which was probably the case this time.

There were still Zond spacecraft available. At this stage, a perfect circumlunar flight was still required before a manned mission could be contemplated. However, a Russian manned circumlunar flight would now, after Apollo 11, make an even more

invidious comparison after Apollo 8. The chances that the cosmonauts would be allowed to fly were fading.

The Russians took advantage of the first of the new series of lunar opportunities opening in the autumn. Zond 7 left Baikonour on 8th August 1969, only two weeks after Luna 15’s demise and at about the time that the Apollo 11 astronauts were emerging from their biological isolation after their moon flight. Thirty turtles had been ready for the mission and four were selected. Zond 7 was the only one of the series to carry colour cameras. Cameras whirred as Zond skimmed past the Ocean of Storms and swung round the western lunar farside 2,000 km over the Leibnitz Mountains. Zond 7 carried a different camera from its predecessors, a 300 mm camera with colour film taking 5.6 cm2 images. Strikingly beautiful colour pictures were taken

of the Earth’s full globe over the moon’s surface as Zond came around the back of the moon. Like Zond 5, voice transmissions were sent on the way back. Zond 7 headed back to the Earth, skipped like a pebble across the atmosphere to soft land in the summer fields of Kustanai in Kazakhstan after 138 hr 25 min. It was a textbook mission.

How easy it all seemed now. After the total success of Zond 7, plans for a manned circumlunar mission were revived and there were still four more Zond spacecraft in the construction shop – one even turned up in subsequent pictures with ‘Zond 9’ painted in red on the side. The state commission responsible for the L-1 Zond programme met on 19th September and the decision was taken to fly Zond 8 as a final rehearsal around the moon in December 1969, with a manned mission to mark the centenary of Lenin’s birth in April 1970, which would be a big national event.

This plan, which was probably designed to appeal to the political leadership, did not in fact win government approval. There were mixed opinions among those administering the Soviet space programme as to whether a man-around-the-moon programme should still fly. Many had serious reservations about flying a mission that would be visibly far inferior not only to Apollo 11 but to the two Apollo lunar – orbiting flights that preceded it. Others disagreed, arguing that the Soviet Union would, by sending cosmonauts to the moon and back, demonstrate at least some form of parity with the United States. In 1970, few other manned spaceflights were in prospect, so a flight around the moon would at least boost morale. The normally cautious chief designer Vasili Mishin pressed hard for cosmonauts to make the lunar journey on the basis that the experience gained would be important in paving the way for a manned journey to a landing later. The political decision, though, was a final ‘no’, the compromise being that Mishin was allowed to fly one more Zond but without a crew. Two of the cosmonauts in the programme subsequently went on record to explain the decision. The political bosses were afraid of the risk that someone would be killed, said Oleg Makarov, who was slated for the mission. Another cosmonaut involved, Georgi Grechko, felt that the primary reason was political: there was no point in doing something the Americans had already done [12]. In the end, Lenin’s centenary was marked, indirectly and two months after the event, by the 18-day duration mission of Andrian Nikolayev and Vitally Sevastianov.

Zond 8 was eventually flown (20th-27th October 1970). It carried tortoises, flies, onions, wheat, barley and microbes and was the subject of new navigation tests. Astronomical telescopes photographed Zond as far as 300,000 km out from Earth to check its trajectory. Zond 8 came as close as 1,110 km over the northern hemisphere of the lunar surface, the closest of all the Zonds. Two sets of black-and-white images were taken, before and after approach. The 400 mm black-and-white camera of the type used on Zonds 5 and 6 was carried. These were high-density pictures, 8,000 by 6,000 pixels and are still some of the best close-up pictures of the moon ever taken [13].

There have been contradictory views as to whether Zond 8 was intended to return to the Soviet Union or be recovered in the Indian Ocean. The records now show that the recovery in the Indian Ocean was deliberate and not the result of a failure. As we know, the optimum trajectory for a returning Zond was to reenter over the southern hemisphere and make a skip reentry, coming down in the normal land recovery zone (Zond 6 and 7), or, if the skip failed, a ballistic descent into the Indian Ocean (Zond 5).

The alternative approach, one favoured by Mishin, was to come through reentry over the northern hemisphere, with good contact with the ground during this crucial period, but make a southern hemisphere splashdown. This route had not been tried before. Two Soviet writers of the period confirm that the purpose of Zond 8 was indeed ‘to make it possible to verify another landing version with deceleration over the USSR’ [14]. Zond 8 made a smooth northern hemisphere skip reentry and came down in the Indian Ocean 24 km from its pinpoint target where it was found within 15 min by the ship Taman. This seemed to prove Mishin’s point. Six years later, though, cosmonauts Vyacheslav Zudov and Valeri Rozhdestvensky splashed down in a lake and very nearly drowned during a protracted and hazardous recovery.

Analysis of the biological samples found similar results across the series. The turtles were hungry and thirsty after their return: hardly a surprise as they had not been fed or watered during their mission. They were examined for changes to their heart, vital organs and blood. There were some mutations in the seeds as a result of radiation. Overall, radiation dosages seemed to be well within acceptable limits, not posting a danger to cosmonauts and not significantly different from conditions in Earth orbit.

Thus, of nine Zond missions and of six attempts to fly to the moon, only Zond 7 and 8 were wholly successful. The last two production Zonds were never used. Just as the Russians tested their lunar hardware in Earth orbit successfully (Cosmos 379, 382, 398,434), they tested their round-the-moon hardware successfully. We now know that the Russians reached the stage where they could, with a reasonable prospect of success, have proceeded to a manned around-the-moon flight. Years later, Vasili Mishin was asked about his period as chief designer and whether he would have done things differently. ‘Perhaps,’ he said wistfully, ‘I would have insisted on making a loop around the moon, even after the United States, because we had everything ready for it. Maybe we could have done it even before the Americans’ [15].

L-l/Zond series: scientific outcomes

• Characterization of Earth-moon, moon-Earth space.

• Mapping of lunar farside.

• Acceptability of radiation limits for biological specimens.

For the rest of the series, the Ye-8-5 was redesigned as the Ye-8-5M. The chief improvement was a much more versatile rail-mounted drill for obtaining samples. This drill was a radical improvement on its predecessors which could only reach 30 cm and the new one was able to penetrate to a depth of no less than 2.5 m. This assignment went to the General Construction Design Bureau of Vladimir Barmin (1909-1993). Barmin was a close colleague of Sergei Korolev and a member of the original council

of designers of 1946. He was the constructor of the cosmodromes, a task of enormous proportions involving the heaviest Earth-moving and digging machinery in the world. Now he got the assignment to make precision drilling equipment for use on another world.

It is possible that the Ye-8-5M missions benefited from the studies of the lunar gravitational environment by Luna 19 and 22. This time the target was the old Luna 15 site at 13°N, 62°E in the large Sea of Crises, a region never explored by the Americans.

Three Ye-8-5Ms were launched, in October 1974, October 1975 and August 1976. Luna 23 entered a lunar orbit of 94 x 104 km, 1 hr 57 min, 138° (12° more than Luna 15) on 2nd November 1974, adjusted on the 6th to a pre-descent orbit of 17 x 105 km. When it tried to land in the southern part of the Sea of Crises on its 50th revolution, it was severely damaged in the course of the landing. The soil-collecting gear was wrecked, although the descent stage was able to continue transmissions for a further three days and contact was lost on the 9th November. It was normal for the descent craft to continue to transmit on 922 MHz for this period, though for what purpose is uncertain, except to relay radiation measurements back to Earth.

It may or may not have been open to the Russians to send the empty return craft back to Earth anyway, but the manoeuvre was not attempted. A replacement mission was organized, but the next Luna failed a year later due to block D failing to ignite.

Finally, Luna 24 entered a circular orbit of 115 km, 1 hr 59 min, 120° on 14th August, adjusted to a pre-descent orbit of 120 x 12 km on the 17th, the lowest of any pre-landing orbits. Amateur trackers in Sweden and Florida picked up its signals on 922 MHz for 20 min on every orbit as it transmitted back to Earth. Luna 24 came down in darkness close to the wreckage of Luna 23 and, it is suspected, at the exact place of Luna 15’s targeted spot, 17 km from the small crater Fahrenheit. Touchdown was on 18th August 1976 and all went well this time. As the rotary percussion rig drilled into the soil, the sample was stored in a rubber pipe in such a way as to prevent clogging and compression. The drill brought up samples weighing 170 g in a 2.6 m long core sample and had been modified in order to minimize grains falling off.

Back on Earth, the same amateur trackers were listening in to Luna 24’s liftoff [13]. Normally, the ascent rocket would begin transmission on 183.6 MHz from the moment of engine burn and continue to transmit during the ascent from the moon. Luna 16 and 20 had spent 1.1 and 1.15 days on the moon respectively, so the same could be expected of Luna 24. But this is not what happened. Instead, Luna 24 lifted off early, after only 0.95 days. For the first time, the lunar liftoff took place with the spaceship in line of sight of Yevpatoria at the moment of liftoff. Hitherto, these liftoffs had taken place when the moon rocket was not in sight of Yevpatoria (though it could be seen by an Atlantic tracking ship), but the final stage of the return journey was in line of sight, which was more important. This time, the Russians must have felt so confident with the return trajectory that it could be accomplished out of sight of Yevpatoria. The return flight was longer than the previous missions, 3.52 days and the spacecraft came back into the atmosphere in a curving trajectory around the back side of the Earth like Zonds 6 and 7, with a recovery zone in Siberia, one never used

before or since. The capsule came down in summertime Siberia 200 km southeast of the tundra town of Surgut and no difficulty was reported in finding it.

Samples were again exchanged with the Americans (3 g) and they were dated to 3.3bn years. Some samples also went to Britain. The post-mission report, given in Pravda on 5th September, related how 60 different chemical elements had been found, dark grey to brown in colour. They appear to be laid down in layers.

Ye-8 series: scientific outcomes

Characterization of lunar soil from three locations: mare, mare core sample and uplands. Characterization, penetration, measurement of lunar soil in situ from two mare locations (Lunokhod, Lunokhod 2), studying density, strength, composition.

Refinement of lunar and interplanetary gravitational field.

Fluxes in radiation levels on moon and in moon orbit over a period of months. Measurement of precise distances between Earth and the moon.

Characterization of local lunar environment in Bay of Rains, Le Monnier.

Mapping of selected areas on lunar nearside.

Measurement of dust levels over daytime lunar surface.

Discovery of thin sheath of ionized gas over sunlight side of lunar surface.

Sea of Clouds

Location of Soviet moon probes

Now that lunar orbit had been achieved ahead of the Americans, the programme could now return to the original, planned Ye-7 lunar-orbiting photography mission. The Ye-7 was renamed the Ye-6LF at this stage. It used the same Ye-6 bus. Instead of the landing cabin, there was a non-detachable cone and box-shaped camera system. Luna 11 carried the same camera system as that flown on Zond 3, which in turn was designed for the 3MV series of Mars and Venus probes over 1964-5. The photographs were expected to cover 25 km2 each, with a resolution of 15 m to 20 m. Once taken, the photographs would be developed and dried. They would then be scanned by a television system on board. Besides the camera system, seven scientific instruments were carried, the same as the Ye-6S, Luna 10. The whole spacecraft weighed around

I, 620 kg.

The first Ye-6LF, with a full photographic suite on board, was eventually launched on 24th August, after the first American lunar orbiter had arrived. Called Luna 11, it left Earth on 24th August and entered moon orbit of 159 by 1,193 km, 27°, 2 hr 58 min. After burning propellant, the mass entering lunar orbit was in the order of 1,136 kg. The Russians had learned their lesson from the Luna 9 episode over the photographs. The Russians faced a choice of sending down pictures only when Yevpatoria was in line of sight, which would take many weeks, or to send them down when stations farther afield, including their own, could pick them up. They decided on the latter course. In a crafty ruse, the decision was taken that transmission would switch rapidly between the two downlink frequencies, too quickly for Jodrell Bank to reconfigure its systems. Moreover, all the photographs were to be taken in the first 24 hours of the mission and transmitted straight away, before this cat-and-mouse technique could be realized or countered.

The Russians reported completion of the mission on 1st October after 38 days, 277 revolutions and 137 communications sessions – but the long-awaited pictures were never published, nor was much else said. Only after glasnost did the Russians admit that the mission had failed in its primary purpose and that the pictures had never reached Earth in the first place. Although the cameras had worked, a problem with the thruster systems meant that the spacecraft had not been pointing at the moon at all, but taking pictures of blank space! This was due in turn to a foreign object getting stuck in one of the thrusters, making orientation impossible. Luna 11 also carried instruments to measure gamma rays, X-rays, meteorite streams and hard cor­puscular radiation. Specifically, it was instrumented to confirm Luna 10’s detection of mascons. The scientific outcomes are not known and few lunar results were attributed to Luna 11. Russian accounts of the scientific results of the 1966 orbiting missions give details of outcomes from Luna 10 and 12, but not 11 [10]. Luna 11 carried, as did its successor, gears and bearings designed to be used on subsequent lunar rovers, to test how they would work in a vacuum.

Luna 12 (22nd October) passed the moon at 1,290 km at a speed of 2,085 m/sec when its retrorocket fired for 28 sec to cut its velocity to 1,148 m/sec to place it into an orbit of 100 by 1,737 km, 3 hr 25 min, in a much narrower equatorial orbit than Luna

II, only 15°. This time, lunar photography was the stated mission objective and

presumably this was accomplished on the first day during the low points of the orbital passes. Thrusters were used extensively to point Luna 12 toward landing sites and on the second day the spacecraft was put into a slow roll so as to accomplish the rest of its mission.

The whole mission lasted three months and ended on 19th January 1967 after 85 days, 602 orbits and 302 communications sessions. The imaging, scanner and relay system had a resolution of between 15 m and 20 m and could be transmitted at either 67 lines/frame for 125 sec (quick look) or at 1,100 lines a frame for 34 min (high resolution). The target areas were the Sea of Rains, Ocean of Storms and craters Ariastarcus and Alphonsus: a Soviet photograph released late in 1966 showed cosmonauts Yuri Gagarin, Alexei Leonov, Vladimir Komarov and Yevgeni Khrunov pouring excitedly over its pictures.

The Russians gave only a short account of the Luna 12 mission, the principal one being Luna 12 transmits, published in Pravda on 6th November 1966 and they released only a small number of images from Luna 12, much inferior in quality to the American

lunar orbiters and doing less than justice to the 15 m resolution of the cameras [11]. There are some reports that the photographs were so poor that the Russians ended up resorting to assembling the publicly available American Ranger and Lunar Orbiter archive to plan their moon landings; but this could be a traditional Western under­estimate of Soviet photographic capabilities. There is no suggestion that anything went wrong, so the pictures must have been at least up to the standards of Zond 3. Because they were taken at much closer range, they were probably much better. Either way, it is more than likely that there are still some Luna 12 pictures deep in some Moscow archive. In addition to cameras, Luna 12 carried a gamma ray spectrometer, magnetometer, infrared radiometer and micrometeorite detector. Assessments were made of the reflectivity of the lunar surface to infer its density (1,400 kg/m3).

Presumably, the Luna 12 pictures would have been decisive in determining where the Russians would land on the moon. The American lunar orbiters enabled the Americans to narrow down the choice of the first landing to five prospective sites, all near the equator (likewise, Luna 12 flew over the equatorial belt, between 15°N and 15°S, in a much narrower band than Luna 11, which operated between 27°N and 27°S). A team in the Vernadsky Institute, led by Alexander Bazilsvsky (b. 1937), worked on site selection for the manned landing from 1968 and also for soil sample and rover missions. Eventually, the Russians selected three smooth areas for the first manned landing on the moon: [2]

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Ye-6LF (originally Ye-7)

Height

Base

Weight (payload) Orbiting altitude Angle to equator Orbital period

Ye-6 series: instruments specified1

Magnetometer.

Gamma ray spectrometer.

Gas discharge counters.

Electrode ion traps.

Meteoroid particle detector. Infrared radiometer.

Low-energy X-ray photon counter. Cameras (Ye-6LF).

Summary of lunar orbiters Ye-6S and Ye-6LF

1 Mar 1966 31 Mar 1966 24 Aug 1966 22 Oct 1966

Meantime, crews were also formed for the landing mission, to fly the LOK and the LK. This included some from the L-1 group. These were also two-person crews, the commander taking the LK down to the surface, making the moonwalk and returning, while the flight engineer circled in lunar orbit. The L-1 experience in flying out to the moon and back was considered important in shaping these selections (a similar consideration was evident in American selections). For the landing mission, the first group of six was formed on 2nd September 1966:

First group of six: Yuri Gagarin, Viktor Gorbatko, Yevgeni Khrunov, Alexei Leonov, Andrian Nikolayev and Vladimir Shatalov.

Yuri Gagarin’s appointment as leader was not as obvious as it looked. Following his flight in April 1961, he had spent several years as a global ambassador for the Soviet Union, a task he had performed with great aplomb. Soviet space chiefs also took the view that he was too valuable to be risked for further space missions. This was a decision he took badly and over 1963-5 he became a more problematical personality and his behaviour declined. In late 1966, he was allowed to resume training and was told he would get an early Soyuz mission, though not the first one. Eventually, he managed to win the assignment of backup to the first Soyuz mission, which eventually flew in April 1967. He took these responsibilities with his old seriousness, his health improved radically and his famous smile reappeared. This assignment meant that he would certainly command the next Soyuz mission.

At this stage there seems to have been a further dispute between those like Kamanin who wanted the cosmonauts to have a hands-on role during their mission; and chief designer Mishin who followed Korolev’s view that there should be a high degree of automation. These arguments were not unknown in the American pro­gramme, though they were resolved at the earliest stage, in favour of the astronauts. By the end of 1967, no progress had been made in the provision of simulators, for they had been cancelled by Mishin. He may have considered them unimportant if most of the flight to and from the moon was under automatic control. Mishin also tried to increase the role of civilian engineers at the expense of the military. In August 1967, he now nominated a group of OKB-1 engineers for the landing mission:

OKB-1 engineer group for the landing mission: Sergei Anokhin, Gennadiy Dolgo – polov, Vladimir Nikitsky (replaced by Vladimir Bugrov), Viktor Patsayev, Valeri Yazdovsky.

The first moves to form a formal moon team for the N1-L3 missions took place in October 1967. The head of the cosmonaut team, General Kamanin, had a preference for veterans and that the LK pilot should have spacewalking experience. This narrowed the field, since only one had such experience, Alexei Leonov, but more would by the time of the mission. The first landing group was selected in December 1967:

Pilots: Alexei Leonov, Andrian Nikolayev, Valeri Bykovsky, Yevgeni Khrunov, Viktor Gorbatko, Boris Volynov, Georgi Shonin, Anatoli Kuklin, Anatoli Filip – chenko, Valeri Voloshin (replaced by Pytor Klimuk).

Engineers: Konstantin Feoktistov, Alexei Yeliseyev, Vladislav Volkov, Valeri Kubasov, Oleg Makarov, Vitally Sevastianov, Nikolai Rukhavishnikov, Valeri Yazdovsky, Georgi Grechko, Vladimir Bugrov.

Training began in January 1968. Some members of the group were already involved in the L-1 Zond programme. This was not seen as presenting a problem, since the landing missions were not then due until 1970-1. The same simulator problem also affected

this group. These cosmonauts did very little training because of the lack of availability of simulators.

Eventually, a 20-person lunar landing group was agreed on 13th March 1968:

Commanders: Valeri Bykovsky, Anatoli Filipchenko, Viktor Gorbatko, Yevgeni Khrunov, Anatoli Kuklin, Alexei Leonov, Andrian Nikolayev, Georgi Shonin, Valeri Voloshin, Boris Volynov.

Engineers: Konstantin Feoktistov, Georgi Grechko, Valeri Kubasov, Oleg Makarov, Vladimir Bugrov, Vitally Sevastianov, Nikolai Rukhavishnikov, Vladislav Volkov, Valeri Yazdovsky, Alexei Yeliseyev. Also assigned: Valentin Yershov.

The cosmonaut team – indeed the whole space programme – suffered a major blow in March 1968 when its leading personality died in a plane crash. Yuri Gagarin had been devastated by the death of Soyuz commander and friend Vladimir Komarov the previous year. Yuri Gagarin had been backup to Komarov and would automatically have been slated to fly the next Soyuz mission, although that had not been decided at that time. After the crash of Komarov he was grounded again, but by the end of 1967, still pressing for a flight, he had been given permission to fly again under strict conditions. On 29th March, experienced instructor Vladimir Seregin and cosmonaut Yuri Gagarin took off on a routine training flight. It seems that their MiG-15 encountered wake turbulence from the jet flow behind an unannounced MiG-21 in the area at the same time, putting their own plane into a spin. They plunged direct into the forest, killing both men outright. His funeral was the biggest there ever was in Moscow. The loss of the young, ever-popular and globally admired Gagarin was a body blow the programme could ill afford.

On 18th June 1968, the final group for the moon landing was selected:

Final group: Valeri Bykovsky, Alexei Leonov, Anatoli Voronov, Yevgeni Khru­nov, Alexei Yeliseyev, Oleg Makarov, Nikolai Rukhavishnikov, Viktor Patsayev.

This was the ‘landing group’ for at least the following year and formed the basis of the assignment for the first two landing crews (the third is more speculative).

Other Soviet equipment for the moon landing was tested. Would the Russian lunar module have worked? Yes, it probably would have, for in 1970-1 the LK was put through a series of exhaustive tests in Earth orbit which it passed with flying colours. Block E of the lunar module had been tested in Zagorsk 26 times, but never in flying conditions.

These were called the T2K tests. The lunar lander, the LK, was tested without its landing legs, since these were primarily propulsion tests of the block E system with its 2.05-tonne thrust, intended to simulate the two major burns of the lunar surface landing and then the subsequent ascent to orbit. The Russians did three tests, all unmanned – while, many years earlier, the Americans had also carried out three (Apollo 5, January 1968, unmanned; Apollo 9, March 1969 and Apollo 10, May 1969, both manned).

The first T2K was launched by a Soyuz rocket on a sunny morning, 24th November 1970, under the designation Cosmos 379, witnessed by its designers. It entered orbit of 192 km to 230 km. On 27th November, after simulating the three-day journey to the moon, the LK fired its variable throttle motor to simulate the lunar landing, descent and hovering over the moon’s surface (250 to 270m/sec AL), changing its orbit to an apogee of 1,120 km. On the 28th, after simulating a day on the surface of the moon, as it were, the LK fired its engine again to model the lunar ascent. Everything went perfectly. This was necessarily a powerful burn, 1,320 to 1,520 m/sec AL). Cosmos 379 ended up in a 14,300-km high orbit, eventually burning up in September 1983.

Further tests of the LK moon cabin were made by Cosmos 398 (26th February 1971) and Cosmos 434 (12th August 1971). On each mission, the landing frame was left in an orbit of 120 km, the ascent cabin much farther out. Cosmos 398 crashed into the South Atlantic in December 1995. In the case of Cosmos 434, the final orbit was 186 by 11,834 km. Unlike the American lander, the landing frame had no propulsive engine in its own right.

The end of the Cosmos 434 mission had a treble irony. Only days after its conclusion, the N1-L3 plan for landing on the moon was cancelled as Mishin persuaded the government to go for a more ambitious lunar-landing plan using a different method, the N1-L3M. Second, that October LK designer Mikhail Yangel invited guests to attend his 60th birthday party, but he died suddenly just as they began to arrive at his home. Hopefully, he realized before his death just what a fine lunar module he had designed and built. Third, in August 1981, Cosmos 434 began to spiral down to Earth. Only three years earlier, a nuclear-powered surveillance satellite had caused a scare when it began to tumble out of orbit. This time, the Soviet Union assured the world there was no need to worry since, because Cosmos 434 was ‘a prototype lunar cabin’, it had no nuclear fuel. This was the first time the Soviet Union had ever publicly admitted, although inadvertently, to the existence of its manned moon-landing programme.

Thankfully, these orbiting Cosmos were not the only LKs completed. Examples of the LK can still be found: in the Moscow Aviation Institute; the Mozhaisky Military Institute of St Petersburg; and at the home of its builder, now called NPO Yuzhnoye, in Dnepropetrovsk. NPO Yuzhnoye has an exhibit of its great engine. And for those contemplating a return to the moon, Yuzhnoye has kept the blueprints too.

The LK tests

24 Nov 1970 Cosmos 379

26 Feb 1971 Cosmos 398

12 Aug 1971 Cosmos 434

What about the LOK and block D? Granted that a working version of the LOK was never successfully launched, it is impossible to comment on its performance. With the flight of Zond around the moon (1969-70) and the requalification of Soyuz (1968-9), it is reasonable to presume that it would have been a successful spacecraft. The first LOK was scheduled to be tested on the fourth flight of the N-1 in 1972. In the meantime, it was decided to proceed with tests of block D for its lunar orbit mission. The types of manoeuvres planned for block D had, unlike Zond and Soyuz, not been tested. Block D engine firings were required for mid-course corrections outbound, to put the complex in lunar orbit and then, second, carry out the powered descent

initiation down to 1,500 m over the surface. They were carried out with a block D attached to a modified Zond and called the KL-1E (‘E’ for experimental).

The first, on 28th November 1969, failed when the first stage of the Proton exploded. The second was Cosmos 382, sent aloft on 2nd December 1970. The manoeuvres simulated the lunar orbit insertion burn, course corrections and the powered descent, respectively. All seem to have gone perfectly. Cosmos 382 aroused some interest at the time. Western experts could not understand why the Russians were flying spacecraft in lunar-type manoeuvres long after Russia had lost a moon race it now claimed it had never been part of.

Block D tests, 1969-70

18 Nov 1969 KL-1E test: failure

2 Dec 1970 KL-1E test: Cosmos 382

Source: Clark (1988, 1993)

Following the success of Soyuz 4 and 5, a further manned Earth orbital test of the lunar orbit rendezvous manoeuvre was planned, similar to those which the United States carried out on Apollo 9. This was called the Kontakt mission, and its specific purpose was to test the rendezvous mechanisms of the LOK and the LK lunar lander. Kontakt was the docking system that would have been used had the original Soyuz complex gone ahead. Kontakt was developed by Alexei Bogomolov of the Moscow Engineering Institute. It might earlier have been used for Soyuz Earth orbital mis­sions, but a rival system called Igla was adopted instead. Kontakt came back into the reckoning for the manned lunar landing, being adopted for the programme partly on account of its simplicity.

Tests of the Kontakt system in Earth orbit were clearly essential before it was committed to lunar orbit rendezvous. These were planned for 1970 and two Soyuz were readied for the mission, one active, one passive. The active crew was Anatoli Filipchenko and Georgi Grechko, the crew for the passive Soyuz was Vasili Lazarev and Oleg Makarov. The mission was assigned high priority, with up to 16 cosmonauts being put through the training programme for the mission. A second, follow-up double mission seems also to have been envisaged. Bogomolov’s delivery of the Kontakt system, originally for 1970, kept slipping. In August 1971, the LOK and LK were abandoned and the missions were formally terminated in October 1971. The four Soyuz in preparation were dismantled and the parts used for other missions.

Luna 24 was the last moon mission by the Soviet Union or Russia. Its return cabin, along with those from Luna 16 and 20, was given to the Lavochkin Museum. Twenty – five such cabins had been built altogether, both for flight and tests. Three still rest on the moon (Luna 15, 18, 23) and five were lost in rocket explosions.

During the period September 1970 to June 1973, a series of missions was promised to build on the successes of the lunar sample return and the Lunokhod. On Luna 16’s return, the Soviet media announced that the 1970s would be ‘the decade of the space robot’. Among the missions spoken about were: [12]

• Telescopes on the lunar farside.

• Automatic static observatories on the moon.

• Use of relay satellites to control and receive information from farside moon probes.

The use of Lunokhods to deliver rocks to a sample return craft would have been impressive. For this, the Lunokhod would have been fitted with a robot arm. Such a mission was sketched in detail and the rover would have been called Sparka, Russian for ‘pair’. Further into the future, VNII Transmash envisaged a ‘heavy Lunokhod’ which looked like an armoured personnel carrier, 4.7 m long, 4.3 m wide, with eight wheels, panels and dish aerials on top, eight 1,200 mm wheels and able to traverse very extensive distances [14].

The extensive discussion of plans for future moon probes in the Soviet press came to an abrupt end in June 1973. References to rovers were now made in the context of their achievements being used to design Mars rovers, rather than future moon rovers. The Soviet media barely reported the last set of missions. It seems that the decision was taken in summer 1973 to wind down the Ye-8 moon programme over the next four years, using up most of the already built hardware. Lunokhod 3 was built and ready to fly in 1977 as Luna 25, but ended up instead in the Lavochkin Museum. Lunokhod 3 was similar to Lunokhod 2, but with an improved camera system. The Proton rocket that should have brought it to the moon was given over to a commu­nications satellite instead.

When Luna 24 returned to Earth, there was no official indication that the programme of unmanned lunar exploration had drawn to a close and, of course, the cancellation at the same time of the N1-L3M programme was not announced either. One winner from Luna 24 was Vladimir Barmin, who was now charged with developing a drill to dig into the rocks of Venus, his new machinery being carried on the forthcoming Venera 11 and 12 missions in 1978.

When Lunokhod 3 was cancelled, the lunar team was dispersed to the Venus missions. Oleg Ivanovsky, the deputy director and responsible for lunar probes, was put in charge of building an orbiting astronomical observatory, called Astron. Once this flew, successfully, in 1983, he retired, taking up a new voluntary post as head of the Lavochkin Museum. Other staff were assigned to other probes and missions.

All the scientists could do was content themselves with publishing the results of their investigations, both in the Soviet press and in collaborative publications abroad.

Despite the heat of the moon race, scientists from the two countries were eager to share and compare the results of their analysis of the results of the moon missions. Many geologists made extensive cross-comparisons of the differences between the three Luna samples and the six Apollo samples, classifying them according to origin, type and composition. Even though the Luna samples were small, they were three distinct types: mare, highland and core. The glassy features of the Luna 16 rock were especially unusual. In the year after Luna 24’s return, NASA published the proceed­ings of the Soviet-American conference on the geochemistry of the moon and planets [15] and Soviet papers were published in other Western outlets, such as the journal The Moon. The NASA papers included the analysis of the moonrock collected by the Lunas and various articles, ranging from studies of the rocks from an individual mission to broader reviews, such as T. V. Malysheva’s The problem of the origin of the lunar maria and continents. Lunokhod 2 produced a rich seam of scientific papers, such as L. L. Vanyan’s Deep electronic sounding of the moon with Lunokhod 2, Measurement of sky brightness from Lunokhod 2 and Dolgov et al.’s: The magnetic field in Le Monnier Bay according to Lunokhod 2. Kiril Florensky’s Role of exogenic factors in the formation of the lunar surface included a series of hitherto unseen Lunokhod 2 pictures. The results of the very last mission were published by Nauka as Lunar soil from the Mare Crisium, by Valeri Barsukov, in 1980.

As for Alexander Kemurdzhian, the designer of the moonrovers, he wrote another thesis about his creations, obtaining a second doctorate and the title of professor. His STR-1 robot was involved in the investigation and cleanup of the Chernobyl nuclear disaster. Kemurdzhian exposed himself to so much radiation there that he had to be treated in the Moscow #20 hospital afterwards. He wrote 200 scientific works and patented 50 inventions. Almost eighty, he retired in 1998, though colleagues noticed little change in his output or energy and he was the chief speaker at the 30th anniversary of the Lunokhod meeting held in Tovstonogov in November 2000. His health deteriorated soon after this and he died on 24th February 2003 in the hospital which had treated him for radiation burns. Alexander Kemurdzhian was buried in the Armenian part of the Smolensky Cemetery in St Petersburg. Asteroid

# 5993 was named after him, and the International Biographic Centre named him one of the outstanding people of the 20th century.

The Ye-8 series did eventually provide the Soviet Union with some form of credible alternative to Apollo and saved some face. The two Lunokhods attracted the most public attention and probably made the most popular impact. They were sophisti­cated vehicles of exploration and it was a loss to science that Lunokhod 3 was not flown. The soil sample return mission series, although technically difficult and impressive in their own right, cannot be said to have been a great success and the gains were achieved for a disproportionate effort. Although three missions did bring lunar samples back, their haul was small at 325 g, compared with Apollo’s 380 kg, while seven missions had failed altogether. The Ye-8LS lunar orbiters may well have achieved solid results, but they were poorly publicized or disseminated. The heart seems to have gone out of the programme in June 1973 and one has the impression that permission was given to fly already-built hardware on the understanding that there would be no further missions thereafter for the foreseeable future. By the time Luna 22 flew, the N-1 programme had been suspended and there was little reason to draw attention to the lunar programme generally. It is probably no coincidence that the last mission, in August 1976, took place only months after the N-1 was finally cancelled in March 1976. It seems that both the manned and unmanned programmes were run down in parallel.

Russia flew a third series of moon probes. These have no direct American comparator. Called the Ye-6LS, little is known about them. Only an outline sketch of Luna 14 has been released (no photographs), showing that it was similar in design to the Ye-6LF. The purpose of the Ye-6LS series was to test out communications between moon orbit and the deep space tracking network, employing the systems to be used later by the manned lunar orbiter, the LOK. Two scientific instruments were also carried: one to measure charged solar particles, the other cosmic rays. One engineering experiment was also carried: more drive gears and lubricants, to test systems to be used on the upcoming series of lunar rovers.

This programme was sufficiently important for three Ye-6LS probes to be flown. The first was launched on 17th May 1967. It was intended that this spacecraft go into a high-Earth orbit reaching out to the full lunar distance, but away from the direction of the moon. In the event, the fourth stage cut out prematurely, leaving Cosmos 159

in a highly irregular orbit, 260 km by 60,710 km. Although falling far short of that intended, the altitude probably was sufficient for a useful test of the LOK commun­ication systems. The second Ye-6LS mission also failed. Block I cut off prematurely 524 sec into the mission on 7th February 1968 when the fuel inlet control jammed and it fell short of Earth orbit.

The only fully successful mission, Luna 14, was flown out to the moon on 7th April 1968 and entered lunar orbit of 160 km by 870 km, 42°, 2 hr 40 min. Russian news agencies said almost nothing about it, except that it carried out studies of the stability of radio signals and the moon’s gravitational field. No one believed them at the time and assumed it was a failed photography mission. In reality, they were telling the truth. It was a test of communications (‘radio signals’) and a mission designed to measure the perturbation of lunar orbits by mascons. Although the discovery of mascons has always been assumed to be American, in fact it can be attributed to Luna 10. Mascons worried both sides equally, for they pulled orbiting spacecraft out of their predicted orbit by several kilometres. These distortions could make all the difference to where a spacecraft was targeted for landing and to the success of subsequent link-ups in lunar orbit. Apollo 11’s Eagle nearly ran out of fuel because its targeting was off-course and Neil Armstrong had to fly the lunar module far downrange to find a suitable area. Instruments were also carried to measure solar wind, cosmic rays and charged particles in lunar orbit, although their outcomes were not publicized. The Russians appear to have been well satisfied with Luna 14’s radio communications tests and mascon mapping, but, because it revealed much about their manned lunar ambitions, drew little attention to the mission.

Ye-6S, Ye-6LF, Ye-6LS series: scientific outcomes (with Zond 3)

Very weak magnetic field around the moon (distortion of the interplanetary magnetic field?). No lunar magnetic poles.

No differences in radiation emission levels between lunar lowlands and highlands.

Cosmic radiation at 5 particles/cm2/sec.

198 meteoroid impacts (Luna 10).

No gaseous atmosphere around moon found.

Finding of anomalous zones of mass concentrations below lunar surface disturbing the lunar orbit (mascons) (Luna 10); characterization of such zones (Luna 14).

Broad composition of lunar rocks (basaltic).

Selection of landing sites for manned and rover landings.

Infrared, ultraviolet scan of lunar surface (Zond 3).

Assessment of reflectivity of lunar surface and inferred density.