Category Soviet and Russian Lunar Exploration

With the flight of Zond 6, the Western press rediscovered the moon race. Time magazine ran a cover of an American and a Russian in a spacesuit elbowing one another out of the way as each raced moonbound. Newspapers printed cutaway drawings of ‘The Zond plan’ and ‘The Apollo plan’. Apollo 8 astronauts Borman, Lovell and Anders were right in the middle of their pre-flight checks. Their Saturn V was already on the pad. In London, Independent Television prepared to go on air with special news features the moment Zond went up. Models and spacesuits decorated the studio. The American Navy even broke international convention to sail eavesdrop­ping warships into the Black Sea to get close to the control centre in Yevpatoria. The Americans had Baikonour under daily surveillance by Corona spy satellites. The whole world was waiting…

The launch window at Baikonour opened on 7th December. No manned Russian launching took place, to the evident disappointment of the Western media. They were of course unaware of the many problems that had arisen on Zond 5 or the even more serious ones on Zond 6. The Russians were in no position to fly to the moon in December 1968.

We now know that there were intense debates within the management of the Soviet L-1 programme in November and that many options were considered. The records of the time, like the Kamanin diaries, are contradictory and even confusing at

times, but they reflected the dilemmas faced by the programme leaders. On the one hand, they did not wish to be panicked into a premature response to what they considered to be the reckless American decision to send Apollo 8 to the moon; at the same time, they realized that, with their Zond experience, they were more prepared for a lunar journey than the Americans. The cosmonauts openly expressed their willingness to make the journey to the moon ahead of Apollo 8 – several report that they sent a letter to the Politburo – but as one government minister commented, ‘they would, wouldn’t they.’ It seems that Mishin’s natural caution prevailed. Years later, Mishin told interviewers that he had recommended to the state commission against such a mission: neither Zond nor Proton were yet safe. The state commission had agreed.

The success of Apollo 8 brought mixed feelings in the Russian camp. Leaders of the Soviet space programme were full of admiration for the American achievement, which they still regarded as a huge gamble. The Americans had gone one stage further than Zond, for Apollo 8 orbited the moon ten times. The Russians were full of regrets that they had not done it first and wondered whether they had made the best use of their time and resources since the first L-1 was launched in March 1967. The head of the cosmonaut squad, General Kamanin, made no attempt to downplay the signifi­cance of the American achievement. I had hoped one day to fly from Kazakhstan to Moscow on an airplane with our cosmonauts after they had circled the moon, he confided in his diary. Now he had the sinking feeling that such a pleasurable airplane flight would never happen.

The state commission overseeing the L-1 project met on 27th December and the safe return of Apollo 8, which took place that day, was very much in their minds. They set dates for the next L-1 launches at almost monthly intervals in early 1969, starting on 20th January 1969. Some asked What is the point?, a moot question granted that such a mission would now achieve less than Apollo 8. The L-1 Zond programme continued, with diminishing conviction, but no one proposed cancellation.

The government’s military industrial commission met three days later on 30th December. The commission underlined the value of unmanned lunar exploration and laid down a new official line on the moon programme. The Soviet Union had always planned to explore the moon by robots and would never risk lives for political propaganda. The Soviet media were invited to advertise the virtues of safer, cheaper unmanned probes. This was the first step in starting the myth, which was the official position for 20 years, that there never had been a moon race. There was little discussion of the moon-landing programme, which was now ready for the first launch of the N-1. A meeting of the party and government on the issue was set for a week later, on 8th January.

By the 21st, Luna 16 had spent a full day on the moon. There was still no official indication as to its purpose. Jodrell Bank reported still more strong signals. In fact, what Luna 16 was doing was checking out its exact landing coordinates so as to give the best possible return trajectory. Luna 16 had landed at the lunar equator at 56°E, the perfect place for the direct return to Earth on Dmitri Okhotsimsky’s passive trajectory. The return system would now be put to the test.

All was now set for the return of the ascent stage to Earth. The top stage of Luna 16 weighed 520 kg, with the recoverable cabin. There was one engine on the ascent stage, the KRD-61 of the Isayev design bureau. Burning 245 kg of UDMH and nitric oxide, the ascent stage had a specific impulse of 313 sec and could burn just once for 53 sec, sufficient to achieve a velocity of between 2,600 m/sec and 2,700 m/sec. A complication of the 2.9 day return flight was that – to recover the spacecraft in the normal Kazakhstan landing site – liftoff would take place out of sight from Yevpatoria: the moon would be over the Atlantic, where it could be followed by a Soviet tracking ship offshore Cuba.

Twenty-six hours after landing, explosive bolts were fired above the Luna 16 descent stage. On a jet of flame, the upper stage shot off and headed towards the white and blue Earth hanging in the distance. It headed straight up, motor still purring, building up to lunar escape velocity, its radio pouring out details from the four aerials poking out the side. The Sea of Fertility returned to the quiet it had known for eons. The descent stage was the only forlorn reminder of the brief visit. The lower stage on the moon continued to transmit signals for a couple of days until the battery ran out. Only two instruments seem to have been carried: a thermometer and radiation counter.

The returning rocket – capsule, instrument container, fuel tanks and motors – reported back from time to time as it headed for a straight nosedive reentry. These coordinates had to be as precise as possible so as to best predict the landing spot on Earth. At 48,000 km out, the tiny capsule separated from the instrument and rocket package, plunged into the upper atmosphere, glowed red and then white as tempera­tures rose to 10,000°C as it hit forces of 350 G. Helicopters were already in the air as a parachute ballooned out at 14,500 m. The capsule hit the ground and beacons began sending out a bright beep! beep! signal as rescuers rushed to collect the precious cargo. The mathematicians had done their job well, for Luna 16 came down 30 km from the middle of the intended recovery zone, 80 km southeast of Dzhezhkazgan, Kazakhstan.

The small capsule was transferred to a plane and flown at once to Moscow to the Vernadsky Institute of Geological and Analytical Chemistry for analysis. The person in charge of assessing the lunar soil was Valeri Barsukov (1928-92), subsequently to become director of the institute (1976-92). How the scientists ever got the soil container open is a mystery for the entire outer skin of the capsule may well have been welded by the intense heat of the fiery return. Once open, the grey grains of moon dust poured out – loose lumps of dark grey, blackish powder like very dark, wet beach sand. It had small grains at the top and large grains at the bottom where it had begun to encounter rock.

The sample, although small (105 g), provided a considerable amount of scientific information [2]. The following were the main features: [11]

It was a tremendous triumph. The Luna 16 mission had gone perfectly from start to finish. The tricky stages of soft-landing, drilling and take-off were just like the book said they should be. ‘It’s the decade of the space robot!’ heralded the Soviet press. The USSR made great play of how such flights were cheaper than manned flights like Apollo, how they did not expose humans to danger and how versatile space robots could land just about anywhere.

For NASA and Western observers the real significance of Luna 16 lay elsewhere: it confirmed what many, but not all of them, had suspected was Luna 15’s real purpose, namely that it was a real challenge to Apollo 11a year earlier. Russia did have good grounds to celebrate Luna 16. Some of the remarks about its low cost and versatility were exaggerated and Luna 16’s sample of 105 g was tiny com­pared with Apollo, each mission of which brought back well over 20 kg. Luna 16 did not have the same capacity to search around for and select samples as the men of Apollo, for the arm would set the drill into the nearest piece of adjacent surface regardless. The Russians later exchanged 3g of Luna 16 samples for 3g each from Apollo 11 and 12. Many years later, the Russians sold 2 mg of soil at Sotheby’s in New York, fetching an out-of-the-world price of $442,500. The results of the soil analysis were published in a number of scientific papers over the following years.

WHERE ARE THEY NOW? LOCATION OF SOVIET MOON PROBES

These are the current locations of Soviet moon probes:

The Soviet moon ship was the LOK (Luniy Orbitalny Korabl). Unlike the L-1 Zond, the LOK had a direct point of comparison with American hardware – the Apollo command-and-service module. Sixteen began construction, seven were completed and parts of four can still be found in museums. The LOK flew only once, on the fourth N-1 launch in November 1972, when it was destroyed, although the descent module was saved by the escape system. The traditional engineering view of the LOK is that it was a beefed-up Soyuz able to fly to the moon, but it was much more capable than that – a versatile lunar spaceship in its own right, a worthy contemporary to Apollo [17].

The descent module was the same as the normal Soyuz – but designed for a crew of two, not three; and with a thicker heat shield for the high reentry speed. The LOK weighed more, 3,050 kg, rather than 2,850 kg. The orbital module was similar to the normal Soyuz, but with different instrumentation, controls and many additional portholes for lunar orbit observations. The spacesuit for the moonwalk would be housed here, and it was from this module that the spacesuited cosmonaut would leave on his moonwalk to climb into the lunar module (LK) and begin the descent to the lunar surface. The orbital module had a large hatch, 90 cm, sufficiently wide to permit the cosmonaut to exit in the Kretchet lunar suit. The orbital module had a control unit for masterminding the link-up in lunar orbit after the landing and a forward-looking porthole. Rendezvous and docking would be controlled from there, not from the descent module.

Compared with Soyuz, it had a much larger skirt at the base, an additional small forward module and a docking system at the front, called Kontakt. A series of antennae and helices were used to zone in on the returning landing module, the LK, for rendezvous and docking. The LOK’s probe, called Aktiv, would penetrate an aluminium plate on the top of the LK. It had 108 recessed honeycomb hexagons on a plate 100 cm across and entry to only one of these would be sufficient to achieve a firm capture.

The most visible differences from Soyuz were in the instrument-and-propulsion module at the rear and the small extra module at the front. The 800 kg front module contained six fuel tanks, each with 300 kg of UDMH, four engines for attitude control in lunar orbit, an orientation engine and the Kontakt docking unit. On Apollo, there was a small conical docking unit on the front of the command module, but the other elements were made an integral part of the service module. For rendezvous, the LOK closed in on the LK in lunar orbit, the flight engineer peering through the forward­looking porthole, using television and handling an adjacent control panel. The front module of the LOK had four attitude control thruster units, each with two main nozzles and two small ones. The engine system was made by the Arsenal Design Bureau in Leningrad.

At the rear, the LOK carried two propulsion sets. The biggest was the main engine for the return to Earth, the equivalent of the Service Propulsion System of Apollo. The LOK’s engine had a thrust of 3,388 kg and a specific impulse of 314 and its primary purpose was to make the trans-Earth injection burn out of lunar orbit. The engine, called the S5.51, was built by the Isayev design bureau. The LOK also carried the standard Soyuz engine, to be used as a rendezvous motor, with a thrust of 417 kg, a specific impulse of 296 and capable of 35 restarts. The LOK carried 2,032 kg of nitrogen tetroxide and 1,120 kg of UMDH. The LOK was the first Soviet spacecraft to carry the fuel cells pioneered by the Americans in the Gemini programme: 20 Volna cells, weight 70 kg, able to supply 1.5 kW for ten days. They were made by the Ural Electrochemical Enterprise. The only other Soviet spaceship to carry fuel cells was the Buran space shuttle in 1988. The rear section carried radiator shutters to shed heat. At the junction with the descent module were star trackers.

LOK’s arrival in lunar orbit followed a different procedure from Apollo. The mid­course manoeuvre and lunar orbit insertion were done by block D, not by the LOK’s main engine. Block D would again be used to lower the orbit of the LOK and LK over the lunar surface to its final orbit dipping to 16 km and, finally, for all but the final part of the powered descent of the LK. On Apollo, the Service Propulsion System carried out the mid-course correction moonbound, lunar orbit insertion and lunar orbit corrections.

With the LK down on the surface, the profile of the LOK now closely approxi­mated that of the Apollo command-and-service module. The LOK would orbit the moon, a sole cosmonaut flight engineer aboard, like the single astronaut on the Apollo. For half of each orbit, it would be around the farside of the moon, out of contact with the Earth. Once the LK blasted off from the lunar surface, it was the task of the LOK to locate the rising LK, close in and dock. The Kontakt system was designed in such a way that a simple contact would join the spacecraft together, so there was no question of hard and soft dockings. Unlike Apollo, the LK cosmonaut would transfer externally back to the LOK by spacewalk. The LK would, like the American LM, then be jettisoned. The LOK would then make the crucial burn out of lunar orbit, make the three day coast back to Earth, carry out two mid-course corrections (one at mid-point, one just before reentry) and then make a Zond-type skip reentry.

Source: RKK Energiya (2001)

What would a Russian Zond around-the-moon mission have been like? The Proton rocket would have been fuelled up about eight hours before liftoff. This is carried out automatically, pipes carrying the nitric acid and UDMH into the bottom stages, liquid oxygen and kerosene into block D. The crew – Alexei Leonov and Oleg Makarov for the first mission – would have gone aboard 2.5 hours before liftoff. Dressed in light grey coveralls and communication soft hats, standing at the bottom of the lift that would bring them up to the cabin, they would have offered some words of encourage­ment to the launch crews overseeing the mission. The payload goes on internal power from two hours before liftoff. The pad area is then evacuated and the tower rolled back to 200 m distant, leaving the rocket standing completely free. There may be a wisp of oxidizer blowing off the top stage, but otherwise the scene is eerily silent, for these are storable fuels. The launch command goes in at 10 sec and the fuels start to mix with the nitric acid. This is an explosive combination, so the engines start to fire at once, making a dull thud. As they do so, orange-brown smoke begins to rush out of the flame trench, the Proton sitting there amidst two powerful currents of vapour pouring out from either side. As the smoke billows out, Proton is airborne, with debris and stones from the launch area flying out in all directions. Twelve seconds into the mission, Proton rolls over in its climb to point in the right direction. A minute into the mission Proton goes through the sound barrier. Vibration is now at its greatest, as are

the G forces, 4 G. The second-stage engines begin to light at 120 sec, just as the first – stage engines are completing their burn. Proton is now 50 km high, the first stage falls away and there is an onion ring wisp of cloud as the new stage takes over. Proton is now lost to sight and those lucky enough to see the launch go back indoors to keep warm. Then, 334 sec into the mission, small thrusters fire the second stage downward so that the third stage can begin its work. It completes its work at 584 sec and the rocket is now in orbit.

Once in orbit, the precise angle for translunar injection is recalculated by the instrumentation system on block D. The engine of block D is fired 80 min later over the Atlantic Ocean as it passes over a Soviet tracking ship. The cosmonauts would have experienced relatively gentle G forces, but in no time would be soaring high above Earth, seeing our planet and its blues and whites in a way that could never be imagined from the relative safety of low-Earth orbit. At this stage, with Zond safely on its way to the moon, Moscow Radio and Television would have announced the

launching. Televised pictures would be transmitted of the two cosmonauts in the cabin and they would probably have pointed their handheld camera out of the porthole to see the round Earth diminish in the distance. The spaceship would not have been called Zond. Several names were even tossed around, like Rossiya (Russia), Sovietsky Rossiya (Soviet Russia) and Sovietsky Soyuz (Soviet Union), but the favourite one was the Akademik Sergei Korolev, dedicating the mission to the memory of the great designer.

Day 2 of the mission would be dominated by the mid-course correction. This would be done automatically, but the cosmonauts would check that the system appeared to be working properly. Although the Earth was ever more receding into the distance, the cosmonauts would see little of the moon as they approached, only the thin sliver of its western edge. Zond’s dish would be pointed at Earth for most of the mission in any case.

Highlight of the mission would be at the end of day 3. Zond would fall into the gravity well of the moon, gradually picking up speed as it approached the swing-by, although this would be little evident in the cabin itself. Then, at the appointed moment, Zond would dip under the southwestern limb of the moon. At that very moment, the communications link with ground control in Yevpatoria would be lost, blocked by the moon. The spaceship would be silent now, apart from the hum of the airconditioning. For the next 45 min, the entire face of the moon’s farside would fill

their portholes, passing by only 1,200 km below. The commander would keep a firm lock on the moon, while the flight engineer would take pictures of the farside peaks, jumbled highlands and craters, for the farside of the moon has few seas or mare. As they soared around the farside, the cosmonauts would be conscious of coming around the limb of the moon. The black of the sky would fill their view above as the moon receded below. As they rounded the moon, they would have seen a nearly full round Earth coming over the horizon, not the crescent enjoyed by Apollo 8. The Akademik Sergei Korolev would reestablish radio contact with Yevpatoria. This would be one of the great moments of the mission, for the cosmonauts would now describe everything that they saw below and presently behind them and as soon as possible beam down television as well as radio. Their excited comments would later be replayed time and time again.

A mid-course correction would be the main feature at the end of day 4. The atmosphere would be relaxed, after the excitement of the previous day, but in the background was the awareness that the most dangerous manoeuvre of the mission lay ahead. The course home would be checked time and time again, with a final adjust­ment made 90,000 km out, done by the crew if the automatic system failed. The southern hemisphere would grow and grow in Zond’s window. Contact with the ground stations in Russia would be lost, though attempts would be made to retain communications through ships at sea. The two cosmonauts would soon perceive Zond to be picking up speed. Strapping themselves in their cabin, they would drop the service module and their own high-gain antenna and then they would tilt the heat – shield of their acorn-shaped cabin at the correct angle in the direction of flight. This was a manoeuvre they had practised a hundred times or more. Now they would feel the gravity forces again, for the first time in six days, as Zond burrowed into the atmosphere. After a little while, they would sense the cushion of air building under Zond and the spacecraft rising again. The G loads would lighten and weightlessness would briefly return as the cabin swung around half the world in darkness on its long, fast, skimming trajectory. Then the G forces would return as it dived in a second occasion. This time the G forces grew and grew and the cabin began to glow outside the window as it went through the flames of reentry, ‘like being on the inside of a blowtorch’ as Nikolai Rukhavishnikov later described reentry. Eventually, after all the bumps, there was a thump as the parachute came out, a heave upward as the canopy caught the air and a gentle, swinging descent. As the cabin reached the flat steppe of Kazakhstan, retrorockets would fire for a second underneath to cushion the landing. On some landings the cabin comes down upright, on others it would roll over. Hopefully, the helicopter ground crews would soon be on hand to pull the cosmonauts out. What a story they would have to tell! What a party in Moscow afterwards! The charred, still hot Akademik Sergei Korolev would be examined, inspected, checked and brought to a suitable, prominent place of reverence in a museum to be admired for all eternity.

Although the Lunokhod was portrayed by the Soviet Union as a safer, cheaper alternative to the manned Apollo missions, in fact the Lunokhod long pre-dated Apollo. Originally, Lunokhod was an integral part of the manned Russian lunar programme. Moon rovers were to pave the way for manned landings by surveying sites before cosmonauts landed, the L-2 programme. They would leave beacons to guide the LK landing ships in. Later, bigger rovers would be landed and cosmonauts were expected to ride them across the moon (the L-5 programme).

The moon rover was originally designed in Korolev’s OKB-1. The preliminary studies were done by Mikhail Tikhonravov in I960. When the Americans first landed a rover on Mars, the Sojourner (1997), it was tiny. By contrast and in typical Soviet style, the Russians started large. Korolev’s team determined that the rover should be at least 600 kg, the size of a small car. This would require a launcher much larger than the Molniya then in design, so Korolev made it a candidate for an early version of the N-1 rocket. Korolev issued the order for the construction of a moon rover in March 1963, but the project progressed slowly and was set back when later that year the state Institute for Tractor and Agricultural Machinery Building declined to develop it, deeming the project to be ‘impossible’.

So, later in 1963, Sergei Korolev instead turned to VNII-100 Transmash of Leningrad, or the Mobile Vehicle Engineering Unit [3]. In September of that year, Korolev met with VNII Transmash engineers to go through the possibilities.

Transmash designed tanks for the Red Army – indeed, during the siege of Stalingrad, tanks were sometimes rolled out of the factory straight up to the front line. The important role of Alexander Kemurdzhian in the Soviet lunar programme emerged only in recent years. He was born on 4th October 1921 in Vladikavkaz and entered the Bauman Technological College in Moscow in 1940. When the war broke out, he went to Leningrad Artillery College and participated in some of the epic battles of the war, such as the crossing of the Dniepr. After the war, he worked on truck design, specializing in transmission systems, for which he obtained a doctorate in 1957. Two years later, he moved into the new area of air cushion vehicles (hovercraft). Kemurdzhian had a personal interest in spaceflight (something he made dear to Korolev) and saw the potential for remote-controlled vehicles exploring the planets. The rover project was no sideshow, for in 1964 it won approval – as the L-2 programme – in the 1964 government and party resolution committing the Soviet Union to going to the moon.

The conceptual study was completed in six months, by April 1964. One of the first problems faced by the designers was the load-bearing capacity of the lunar soil, for this would govern chassis, power systems and wheel design. Until such time as soft – landers tested the surface, it would be impossible to know the answer for definite. In an attempt to make the best possible estimate, a conference of lunar and astro­nomical experts were gathered at Kharkov University that year, hosted by Professor Barabashev and also attended by Professor Troitsky of Gorky University and Pro­fessor Sharanov of Leningrad University. In the event, their estimates were broadly

correct, being confirmed by Luna 13 two years later. First design sketches were concluded in September 1965.

The rover project was turned over, along with all the other unmanned lunar and interplanetary programmes, to OKB Lavochkin in 1965. Kemurdzhian worked closely with the director of OKB Lavochkin, Georgi Babakin, to finalize what was then called in 1966 the Ye-8. The Ye-8 was originally intended to pave the way for the manned lunar landing. Before the first Ye-8 landed, suitable sites would first be selected by a close-look lunar orbiter. To do this, a version of the rover was adapted for a photography mission in lunar orbit to select a main landing site for the lunar landing, but there was also a reserve one nearby, not more than 5 km distant. Two Ye-8s would then be landed, one at the main site, one at the reserve. These would confirm the suitability of both sites for the manned lunar landing. In an elaboration of the plan, an unmanned LK would be landed near the rover at the reserve site and checked out to see that it was in good working order. If when he landed his LK was disabled, the sole cosmonaut could travel to the reserve LK to return to Earth. In a further version, the cosmonaut could use the rover to travel across the lunar surface from the main site to the reserve site.

A number of designs using different numbers of wheels were considered in the course of 1965-6. The designers considered tractors, walkers and even jumpers, from caterpillar to four-wheel designs. The very first rover design was for a dome carried on four caterpillar wheels, very like a tank. The first rovers were designed to weigh nearly a tonne, about 900 kg. When it was apparent that the N-1 would not become quickly available, the Ye-8 was scaled down so that it could be accommodated within Chelomei’s UR-500K Proton. The final rover design was for an unmanned rover. In a further modification of the original plan, the Ye-8 would be launched before the Ye-8LS lunar orbiter, the opposite of what had been intended.

The rover design was settled in 1967 and a 150 kg scaled prototype was constructed in Leningrad that year. A version was tested in the volcanic region of Kamchatka in the Soviet far east, which was the Earth’s surface closest in character to the moon. Models were tested in the Crimea and early versions of the transmission gears and wheels were flown out to the moon on Luna 11 and 12 in 1966 and Luna 14 in 1968. Even though it had been scaled back, the final rover was still a substantial piece of engineering. The vehicle, to be called ‘Lunokhod’ or ‘moon walker’ in Russian, weighed 756 kg and was 4.42 m long (lid open), 2.15 m in diameter and 1.92m high. Its wheel base was 2.22 m by 1.6 m. The main container was a pressurized vehicle, looking like an upside down bathtub, carrying cameras, transmitters and scientific instruments. It was kept warm by a small decaying radioisotope of 11 kg of polonium-210. The eight 51 cm diameter wheels were made by the Kharkhov State Bicycle Plant, made of metal with a mesh covering. There was a ninth wheel behind the vehicle to measure distance. Each wheel had its own electric motor. In the event of one wheel becoming completely stuck, a small explosive charge could be fired to sever it. The vehicle was designed to climb slopes of 20° and manage side slopes of 40 to 45°. The main designers were, aside from Kermurdzhian himself, Gary Rogovsky, Pavel Sologub, Valery Gromov, Anatoli Mitskevich and Slava Mishkinjuk.

To guide the route chosen, Lunokhod had four 1.3 kg panoramic cameras similar to those on Luna 16 to scan 360° around the rover and two television cameras to scan forward, with a 50° field of view and 1/25 sec speed. The scan of the panoramic cameras was designed in such a way as to cover the horizon right around to parts of the rover and its wheel base. They provided high-resolution images, 6,000 x 500 pixels. Signals were sent back by both an omnidirectional and narrow-beam antenna. The driving camera relayed pictures back to Earth every 20 sec and these enabled a five-person ground crew to drive the Lunokhod: commander, driver, navigator, engineer and radio operator. The rover could go forwards or backwards. Gyroscopes would stop the rover if it appeared to tilt too much forward or backward or to one side.

The selection of the ground crew was an important part of the programme. Two five-man crews were selected from the Missile Defence Corps in 1968 [4]. Volunteers were sent for tests for speed-of-reaction times, short and long-term memory, vision, hearing and capacity for prolonged mental focus and attention. At one stage of their recruitment, they thought they were being trained as cosmonauts. They were under strict instructions not to talk about their work to outsiders. Years later, their names became known. They had been recruited by the Strategic Rocket Forces in the late 1960s when the call had gone out for ‘top class military engineers. Young but experienced. Sporting and in a good state of health.’ Twenty-five were chosen and sent to Moscow for a special mission, they did not know what. They were put through a series of tests in the Institute for Medical and Biological Problems, where the group was reduced by eight. Then, the seventeen remaining were told that they would be driving machines across the surface of the moon, whereupon three resigned, saying that the responsibility and stress would be too much for them. The fourteen remaining were divided: half were sent off to Leningrad to the VNII-100 design bureau where the Lunokhod was built and the other half were assigned to work on the design with the Lavochkin design bureau. In 1968, construction began of a ‘lunardrome’ in Simfer­opol in the Crimea, and the driving teams spent the rest of the year there learning how to drive a Lunokhod model.

Lunokhod carried a number of scientific instruments: a French-built 3.7 kg laser reflector, designed to measure the precise distance between Earth and the moon; a RIFMA X-ray fluorescent spectrometer to determine the composition of moonrock; an X-ray telescope; a cosmic ray telescope; and a penetrometer. An energetic particle detector was built by Dr Yevgeni Chuchkov of the Theoretical and Applied Physics Divison of the Skobeltsyn Institute of Nuclear Physics of the Moscow State Univer­sity, calibrated against similar instruments flown on Zond 1 and 3 and the early Mars and Venera probes.

To get Lunokhod onto the lunar surface, the KT stage was used, of the same type as Luna 15 and 16. This was a frame-shaped spacecraft with a toroidal fuel tank; radar; attitude thrusters; 11D417 engine of between 0.75 and 1.92 tonnes of thrust for mid-course correction, lunar orbit insertion and landing; batteries; and communica­tions. The Lunokhod rested atop the descent stage, and – when the moment came – landing ramps would deploy at either side so the rover could descend to the moon at an angle of up to 45°.

Lunokhod instruments

Laser reflector.

RIFMA (Roentgen Isotopic Fluorescent Method of Analysis) X-ray fluorescent spectrometer. Extra-galactic X-ray telescope.

Cosmic ray background radiation detector.

PrOP (Pribori Ochenki Prokhodimosti) penetrometer.

Ultraviolet photometer (Lunokhod 2 only)

Any benefit that was gained by the success of Luna 16 was turned to double advantage just two months later by Luna 17. The sample return, pushed to the back page by the eruption of political violence in the Middle East, had made little public impact. The same could not be said of its successor, put up on 10th November 1970. The spaceship weighed about 5,750 kg.

BIBLIOGRAPHICAL NOTE

Any book on Soviet and Russian lunar exploration has to face problems of infor­mation sources and their reliability. Even such apparently mundane and non­controversial matters as the paths taken by Soviet spacecraft as they circled the moon and the precise coordinates as to where they landed can be problematic, with official sources quoting different and even contradictory details – and then revising them! During the peak of the moon race, the official organs of Soviet government issued an economy of information on certain spacecraft and even disinformation on others. There is no official, comprehensive authorized history of the Soviet moon programme, which makes the assembly of the story all the more challenging, interesting and necessary. I have tried to put together the most accurate sources that best fit the known facts, ‘the best version of the truth available’ – but over time these will be superseded as new information sources become available. The story of the Soviet/ Russian moon programme is still, as the saying goes now, a ‘site under construction’.

A book such as this invariably relies on a variety of diverse sources. Some of the main elements are outlined here. First, there has long been a Western tradition of analyzing the Soviet lunar programme, putting together the best possible version of the truth available from official statements, Western intelligence analysis and an examination of trajectories and orbits. Here, Stoiko (1970) and Gatland (1972) were the pioneers, both giving due prominence to the lunar programme. They were followed by Clark (1988-2005) who has made multiple, penetrating, in-depth analyses of the performance of Soviet spacecraft and has invariably been vindicated by the official story emerging years later. Their work has been supplemented by specialized studies such as those of: Vick in analysing Russian rockets and launch facilities (1994­6); Rex Hall, who identified the members of the cosmonaut squad and their roles

(1988-2003); Gordon Hooper (1990), who assembled their biographies; and Jim Harford (1997), who penned the authoritative biography of Sergei Korolev. Others have brought different knowledge to bear – for example, in the area of tracking (Sven Grahn); the analysis of hardware (David Portree, 1995; Nicholas Johnson, 1994); the performance of rockets (Berry Sanders, 1996-7); and the development of space equipment (Don P. Mitchell). Mark Wade and Anatoli Zak have done much to assemble what is now known of the Soviet moon programme and make it globally and readily available on the Internet to amateurs, professionals and historians alike. Recently, Pesavento and Vick (2004) wrote a lengthy heretical series in the historical magazine Quest, re-opening the debate about Soviet lunar capabilities and intentions during the pivotal years 1968-9.

Following Soviet accounts of their early lunar programme required a challenging effort to separate the respective strands of reporting, science, human interest, engin­eering and achievement, news management and even disinformation. Soviet lunar missions were publicized in standard English language outlets, such as Radio Mos­cow’s World Service, magazines, periodical and miscellaneous grey literature (e. g., Science and Life, Soviet Weekly, Sputnik, Soviet booklet series). These were all used where they were available. Scientific outcomes were published in a number of special­ized international journals.

The precise nature of the Soviet lunar effort did not become clear until a number of designers, scientists and journalists were given or took the opportunity to speak more openly about the Soviet side of the moon race. Most prominent of these was Chief Designer Vasili Mishin (1990), but he was accompanied by a number of scientists, journalists and colleagues, such as Leskov (1989), Chernyshov (1990), Rebrov (1990), Filin (1991), Afanasayev (1991) and Lebedev (1992). On its 50th anniversary, in 1996, the Energiya design bureau published its official history, full of hitherto unknown details of its moon programme. Russian journalists and space enthusiasts have now been able to tell the story of their country’s space programme. In a detailed 13-part series, Varfolomeyev (1995-2002) has reconstructed, for Space­flight, the technical history of many of the key rocket programmes of the period. Perhaps the most remarkable contemporaneous document from the period was the diary of the head of the Soviet cosmonaut squad, General Nikolai Kamanin, whose record has been painstakingly and faithfully reconstructed by Hendrickx (1997-2002), whose endeavours in translating and interpretation are an enduring contribution to history. Cosmonauts (e. g., Alexei Leonov) and designers (e. g., Chertok) have now written memoirs. Soviet historical documentation from the period has now become more widely available and here Siddiqi (2000) has made the most impressively scholarly interpretation, one likely to be the principal point of reference for many years.

As the generation that managed the Soviet lunar programme begins to pass on, the preservation of that record becomes more important. In recent times, writers such as Yuri Surkov (1997) have now come to publish the scientific results of Russian lunar and planetary exploration. The first attempt to assemble a web-based inventory of Soviet lunar science was undertaken by the American space agency, NASA, where the Goddard Spaceflight Centre began to put together an archive of Soviet lunar and planetary science which was made available on the Internet in the NSSDC Master catalogue.

[1] os is Old Style, the calendar in use before the Bolshevik revolution, which ran twelve days behind the rest of Europe. New style dates are given for those born after the revolution.

[2] Ocean of Storms;

• Sinus Meridiani; and

• Sea of Tranquility (not the Apollo 11 site).

[3] Lunar orbit insertion (110 km).

• Lunar orbit adjustment (110 km by 16 km).

• Descent to the moon.

[4] Although the rocket would be built in Kyubyshev and Moscow, it would be assembled and integrated at Baikonour Cosmodrome, saving transit time.

• Savings would be made on ground testing. Although engines would be tested individually, there would be no testing of all the first-stage engines together on a dedicated test stand. This was in dramatic contrast with the United States, where the large new F-1 engines were tested in large-scale facilities in Huntsville, AL.

[5] The selection of cosmonauts for the general moon programme.

• The division of this group into candidates to train for the around-the-moon flight (L-1) and the moon landing itself (the LOK and the LK). Some cosmonauts belonged to both.

• Selection of cosmonauts for the first around-the-moon and landing missions.

• Decline and disbandment of the group. All then returned to mainstream missions.

[6] Alexei Leonov and Oleg Makarov;

• Valeri Bykovsky and Nikolai Rukhavishnikov;

• Pavel Popovich and Vitally Sevastianov;

• Valeri Voloshin and Yuri Artyukin; and

• Pytor Klimuk and Anatoli Voronov.

[7] Improved aerodynamics, with reduced diameter down from 17 m to 15.8 m.

• Four new vernier engines to improve roll control.

Real L-1S, dummy LK Real L-1S, dummy LK Mockup LK, mockup LOK Real LOK, dummy LK Real LOK, LK, block D

The descent of the Soviet lunar lander, called the LK (Luniy Korabl), to the lunar surface would be a steep one. The final lunar orbit would be 16 km by 85 km, the same as the final orbit of the later Ye-8-5 lunar sample return missions. Block D would fire at the 16 km perilune, bringing the LK to between 2 km altitude (maximum) and 500 m (minimum), ideally 1,500 m. If all went well, the LK pilot would set the LK down about 25 sec thereafter, but not more than a minute later. The LK would descend to 110 m, when it would hover: then the cosmonaut would take over for the landing. The instructors told the cosmonauts that at 110 m, they had three seconds to select a landing site, or return to orbit (‘as if returning at this stage was an option’, snorted Leonov). The standing cosmonaut, watching through his large, forward-looking window, would guide the LK lander with a control stick for attitude and rate of descent.

The engine, called block E, was designed by the Mikhail Yangel OKB-586 in Dnepropetrovsk. It was a well-equipped propulsion set. The LK module had:

• One 11D411 RD-858 main engine weighing 53 kg with a single nozzle with a specific impulse of 315 sec, chamber pressure of 80 atmospheres and duration of 470 sec.

• A 11D412 RD-859 57 kg backup engine with two nozzles.

• Four vernier engines.

• Two 40 kg thrusters for yaw.

• Two 40 kg thrusters for pitch.

• Four 10 kg thrusters for roll.

The descent and take-off engine was a throttlable, single-nozzle, 2.5-tonne rocket burning nitrogen tetroxide and UDMH. It could be throttled between 860 kg thrust and 2,000 kg. The engine held 1.58 tonnes of nitric acid and 810 kg of UDMH. The engine had four verniers to maintain stability. For attitude control during the nerve – wracking descent to the moon, eight low-thrust engines designed by the Stepanov Aviation Bureau fed off a common 100 kg propellant reserve. The system was both safe – it ran off two independent circuits – and sensitive, for thrust impulses could last as little as nine milliseconds. To land the LK, the cosmonaut had a computer-assisted set of controls, the first carried on a Soviet manned spacecraft. The S-330 computer was a sophisticated digital machine, linking the cosmonaut’s commands to the land­er’s gyroscopes, gyrostabilized platform and radio locator, with three independent channels working in parallel [18]. Four upward-firing solid rockets would ignite on landing, to press the LK onto the surface. The lander was designed to take a slope of 20°.

The LK was different from the Apollo lunar module (LM) in a number of important respects. These were a function of the much poorer lifting power of the N-1 rocket. First, it was much smaller, being only 5.5 m tall and weighing 5 tonnes (the LM was, by contrast, 7 m tall and weighed 16 tonnes). It had room for only one cosmonaut standing and the lower stage would have no room for the extensive range of scientific instruments carried by Apollo. Second, the LK had a single 2,050 kg thrust main engine which was used for both descent and take-off (Apollo’s LM had a descent motor and a separate one for the small upper stage). Like the LM, the LK would use the descent stage as a take-off frame. The LK was designed for independent flight of 72 hours and up to 48 hours on the lunar surface. The LK was a minimalist approach to a lunar landing. Although the method of landing on and take-off from the moon was broadly similar, there were some important differences:

• The American LM descent engine carried out the entire 12 min descent from PDI (powered descent initiation) to touchdown. By contrast, block D provided most of the thrust of the descent of the Soviet LK. Block D was dropped around 1,500 m above the surface and the LK’s descent stage took over for the final part.

• The American LM had two motors, one for descent and one for ascent. By contrast, the Russian LK had just one motor, which was used for descent and ascent.

What would the LOK-LK mission have been like? It would begin with the launching, from Baikonour Cosmodrome, of two cosmonauts on the N-1 rocket. The three stages

of the N-1 rocket would burn until the lunar stack was safely in an Earth orbit of 51.6°, 200 km. At the end of the first parking orbit, the fourth stage, block G, would fire for translunar injection. This block would then separate.

Unlike Apollo, there would be no transposition, docking and ejection of the lunar module. This would remain behind the command ship, the LOK, as they headed moonward. On the way to the moon, the fifth stage, block D, would fire for a translunar correction. Three days into the mission, block D would fire the stack into lunar orbit. The descent from lunar orbit would again be different from Apollo. First, a lone cosmonaut would enter the lunar module, the LK. Because there was no internal hatch, the cosmonaut would exit the hatch and climb down the side of the LOK along a pole before entering the access hatch. This would take place against the backdrop of the moon’s surface below and the spectacle would be stunning. Once on board the LK, the cosmonaut would then separate his lunar module and block D from the LOK mother ship. Here would come a fresh difference. The powered descent

burn would be done by block D. It would be jettisoned a mere 1,500 m above the lunar surface, leaving the LK’s main engine to complete the descent to the lunar surface. This would be the same engine used for take-off.

Hover time was much tighter on the Russian LK than the American LM. The Russians had about a minute to find the landing site and put the spacecraft down. The pilot could, of course, use more than 1 min, since it was the same engine used for the ascent, but this would eat into the thrust required for ascent. The LM had a longer hover time, about 2 min. By the end of the 2 min, the LM would be out of fuel and the mission would have to abort. Below a certain altitude, the period of time for firing the ascent stage would be longer than the time taken to fall to the surface, so the LM would crash (this was called ‘dead man’s handle’). All but one of the Apollos were sufficiently well targeted not to present a problem. The most difficult landing was the first, Apollo 11, which landed with only 19 sec of fuel to spare. ‘Dead man’s handle’ did not operate on the LK, since the engine used for the ascent was already firing. Arguably, it was safer. The LK lunar lander, like Apollo, had four legs. The first Soviet moon landing would have been shorter than that of Apollo 11, without a sleep period.

Once on the surface, the sole cosmonaut would carry out a spacewalk. We do not know how long the first lunar stay was planned. A moonwalk duration of four hours has been suggested, so the surface stay time would have to be long enough to report back after landing, prepare for the moonwalk, carry it out, return and prepare for take-off and rendezvous.

After several hours on the surface, the cosmonaut would lift off from the moon in the upper stage of the LK, and conduct the type of rendezvous pattern tested by Cosmos 186-188, 212-3 and Soyuz 2-3 and 4-5 in which the LOK orbiter performed the active role. A backup two-nozzle engine was also available should the motor fail to light for the critical liftoff from the moon. On liftoff, the backup engine was actually fired simultaneously with the main engine, but turned off if the main engine lit up. The LK had five chemical batteries, three on the descent stage, two on the ascent. Cabin pressure was oxygen/nitrogen at 560 mm.

The return-to-Earth profile was quite like Apollo. The LK would lift off from the lunar surface, using the landing frame as a launching pad, like the American LM. The LK would link up with the LOK in lunar orbit and the cosmonaut would transfer to the LOK, though this would be by an external spacewalk (indeed, it would be his third that day). The LK would be dropped, and then the LOK would fire its main engine for trans-Earth injection. There would be a quiet coast Earthward, followed by a high­speed skip reentry over the Indian Ocean and a soft landing in Kazakhstan.

The LOK and L-1 spacecraft were expected to return to Earth in the standard recovery zone in Kazakhstan. Here, the Russians had extensive experience of the Air Force recovering spacecraft using helicopters, trucks, amphibious vehicles, adapted troop carriers and other vehicles able to traverse the flat steppeland. This experience had been built up during the Korabl Sputnik missions and the Vostok series and consolidated as the military photoreconnaissance Zenit series began making regular missions. The real problem was if the L-1 or LOK came down outside Soviet territory, either by choice or if the skip return failed and a ballistic path was followed instead. The Indian Ocean was the most likely maritime landing point. Here, in a decree issued on 21st December 1966, the Soviet Navy was made responsible for Indian Ocean recoveries. For Indian Ocean recoveries, ten naval and maritime research ships were involved, supplemented by three ship-borne helicopters, spread out at 300 km points along the ocean.

The LK

Weight 5,500 kg

Height 5.2 m

Diameter ascent stage 3 m

Span, descent stage 4.5 m

Habitable volume 4m3

Hover time 1 min

Weight, ascent stage 2,250 kg

Weight, descent stage 2,250 kg

Crew 1

Length of legs 6.3 m

Were Soviet computers up to the job? The Apollo 11 American lunar landing nearly aborted when the lunar module’s computer overloaded and flashed alarms in the LM cabin. The Apollo computers, though the most sophisticated of their day, would be regarded as laughably primitive nowadays. They were bulky, crude and had limited memory, but they played an important part in getting Apollo to the moon and back again. The popular assumption is that Soviet computers during the moon race lagged far behind American ones. This does not seem to be the case now. The Soviet Union had a long tradition in advanced mathematics and developed, in the late 1950s, its own silicon valley, partly assisted by two exfiltrated American electrical engineers, com­munists and friends of the Rosenbergs, Alfred Sarant and Joel Barr [19]. Taking on fresh names, Philip Staros and Josef Berg, they built up Special Design Bureau 2 (Spetsealnoye Konstruktorskoye Buro 2, SKB 2) which developed microcomputers for the Soviet aviation industry, military and space programmes. This included the Argon computer used on Zond. During the 1960s, SKB 2 developed a series of small, lightweight, sophisticated computers, from laptops to navigational devices to big calculating computers. Just because Soviet computers followed a different develop­ment path from the West did not mean that they were inferior, for they were not. The ability of the USSR to achieve automated rendezvous and docking in space (1967) went unmatched in the West until 1998 when the Japanese satellites Hikoboshi and Orihime met in orbit.

The success of Apollo 8 presented Soviet space planners with a double problem: how should they modify their programme in the light of America’s success; and how should these changes be presented to the world? A joint government-party meeting was held on 8th January, a week into the new year. Feelings among ministers and officials verged on panic and they must now have got an inkling as to how the Americans must have felt after the early Soviet successes. Thus, a new joint resolution of the party and the Council of Ministers, # 19-10, was passed on 8th January 1969. They agreed, in a bundle of decisions:

• The L-1 programme would continue, although the majority took the view that there would be little point in conducting a mission now clearly inferior to the achievement of Apollo 8.

• The programme for the N-1 would also continue, although it was apparent that it would fall short of what the Americans planned to achieve under Apollo, quite apart from running several years behind. Once successfully tested, the N-1 could be reconfigured for a mission that would overtake Apollo. Manned flights to Mars in the late 1970s were mooted – ironically the original mission for the N-1.

• Unmanned probes to the moon, Mars and Venus would be accelerated. The public presentation of the Soviet space programme would emphasize these goals.

• Ways would be explored of accelerating a manned space station programme, Vladimir Chelomei’s Almaz project.

Although they now realized that their chances of beating the Americans to the moon had now sharply diminished, there was no support for the idea of abandoning the

moon programme. Although this was nowhere written down, there was probably the lingering hope that America’s rapid progress might hit some delays. But, in their hearts they must have known that basing their progress on the difficulties of others was not a sound basis for planning. This was not how the Soviet space programme worked in its golden years.

Now came a new generation of unmanned Russian moon probes, following the first generation (1958-60, Ye-1 to Ye-5) and the second (1963-8, Ye-6 and Ye-7). These were substantially larger and designed to be launched on the Proton rocket and called the Ye-8 series, of which the programme chief designer was Oleg Ivanovski. There were three variants:

Ye-8 Lunar rover (Lunokhod) (originally the L-2 programme)

Ye-8-5 Lunar sample return

Ye-8LS Lunar orbiter

Although finally approved in January 1969, these missions had actually been in preparation for some time in the Lavochkin design bureau. Available first was the moon rover, or Lunokhod, the Russian word for ‘moonwalker’, and it was nearly ready to go. Although the Soviet Union portrayed the Lunokhod series as a cheap, safe, alternative to Apollo and although Lunokhods followed the American landings, the original purpose of the series was to precede and pave the way for Russian manned landings. Ideas of lunar rovers were by no means new and dated, as noticed earlier, to the 1950s. Design work had proceeded throughout the 1960s. The moon rover was intended to test the surface of the intended site for the first manned landing; later versions would carry cosmonauts across the moon. Indeed, they were endorsed in science fiction. The story of Alexander Kazanstev’s Lunnaya doroga (Lunar road) was how a Soviet rover rescued an American in peril on the moon [1].

At the other extreme, the lunar sample return mission had been put together at astonishingly short notice. By early 1967, the design of the Ye-8 lunar rover had been more of less finished. The Lavochkin design bureau figured out that it might be possible to convert the upper age, instead of carrying a lunar rover, to carry a sample return spacecraft. The lower stage, the KT, required almost no modification and could be left as it was. Now on top sat the cylindrical instrumentation unit, the spherical return capsule atop it in turn and underneath an ascent stage. A long robot arm, not unlike a dentist’s drill, swung out from the descent stage and swivelled round into a small hatch in the return cabin. The moonscooper’s height was 3.96 m, the weight 1,880 kg. The plan was for a four-day coast to the moon, the upper stage lifting off from the moon for the return flight to Earth. The mission was proposed as insurance against the danger of America getting a man on the moon first. At least with the sample return mission, Russia could at least get moon samples back first. The sample return proposal, called the Ye-8-5, was rapidly approved and construction of the first spacecraft began in 1968.

Sample return missions were designed to have the simplest possible return trajectories. Originally, it was expected that a returning spacecraft would have to adjust its course as it returned to Earth. In the Institute of Applied Mathematics,

Dmitri Okhotsimsky had calculated that there was a narrow range of paths from the moon to the Earth where, if the returning vehicle achieved the precise velocity required, no course corrections would be required on the flightpath back and the cabin could return to the right place in the Soviet Union. This was called a ‘passive return trajectory’. Such a trajectory was only possible from a limited number of fairly precise landing cones between 56°E and 62°E, and these were calculated following Luna 14’s mapping of the lunar gravitational field. Returning from one of these cones meant that Luna could just blast off directly for Earth and there was no need for a pitch-over during the ascent, nor for a mid-course correction. If it reached a certain speed at a certain point, then it would fall into the moon-Earth gravitational field. Gravity would do the rest and the cabin would fall back to Earth. On the other hand, the passive return trajectory limited the range of possible landing spots on the moon, meant that the actual landing spot must be known with extreme precision (±10 km), the take-off must be at exactly the right second and the engine must achieve exactly the right velocity, nothing more or less [2]. Sample return missions had to be timetabled backward according to the daytime recovery zone in Kazakhstan and the need to have the returning cabin in line of sight with northern hemisphere ground tracking during its flight back to Earth. Thus, the landing time on Earth determined the landing point and place on the moon, and this in turn determined when the probe would be launched from Earth in the first place.

The Ye-8 series all used common components and a similar structure. The base was 4 m wide, consisting of four spherical fuel tanks, four cylindrical fuel tanks, nozzles, thrusters and landing legs. Atop the structure rested either a sample return capsule, a lunar rover or an instrument cabin for lunar orbit studies. By spring 1969, the time of the government and party resolution, Lavochkin had managed to build one complete rover and no fewer than five Ye-8-5s and have them ready for launch. In the case of the ascent stage, a small spherical cabin was designed, equipped with antenna, parachute, radio transmittter, battery, ablative heatshield and container for moonrock.

The first Lunokhod was prepared for launch on 23rd February 1969 and was aimed at the bay-shaped crater, Le Monnier, in the Sea of Serenity on the eastern edge of the moon [3]. The timing of the Lunokhod missions was affected by the need to land in sufficient light to re-charge the rover’s batteries before the onset of lunar night. It had been arranged that when it drove down onto the lunar surface, a portable tape recorder would play the Soviet national anthem to announce its arrival. Proton failed when, 50 sec into the mission, excessive vibration tore off the shroud and the whole rocket exploded 2 sec later, the remains coming down 15 km from the launch site. For months, the military tried to find the nuclear isotope that should have powered the rover across the surface of the moon. Apparently, some local troops downrange on sentry duty found it and, clearly insufficiently briefed about the dangers of polonium radiation, used it to keep their patrol’s hut warm for the rest of that exceptionally cold winter. Parts of the lunar rover were found – wheels and part of the undercarriage – and were remarkably undamaged. Even the portable tape recorder was found, playing the Soviet national anthem on the steppe, not Le Monnier bay as had been hoped [4].

Luna 17’s mission was, at least for its first six days, apparently identical to that of Luna 16 and 15. A four-day coast out to the moon was followed by lunar orbit insertion circular at 85 km, 1 hr 56 min, 141°. On the 16th, the onboard motor lowered the orbit to an altitude of 19 km. Luna 17’s target was nearly a hemisphere away from that of Luna 16. The entire western face of the moon is dominated by a huge, dark ‘sea’ which is called the Ocean of Storms. In its northwest corner is a semi-circular basin, the Sea of Rains.

After only two days in orbit, reflecting the bright sunlight of the setting sun, Luna 17 skimmed in low over the Jura Mountains. The retrorocket fired. Luna 17 came down as the radar checked the landing site. At 600 m, coming down at 255 m/sec, the final main engine burn was made. Down it came, as softly as a parachutist on a wind – free day. By the time it landed, Luna 17 weighed 1,836 kg. The long shadows of the structure stood out starkly toward the darkening east. For two hours, Luna 17 reported back its position. Russia coolly announced its fourth soft-landing on the moon. A return capsule would be fired back to Earth the next day – or so everyone

Not so. On the upper stage rested the first vehicle designed to explore another world. It had eight wheels, looking like pram wheels, which supported a shiny metallic car, covered by a kettle-style lid. Out of the front peered two goggle-like television eyes. Above them peeped the laser reflector and two aerials. It was an unlikely-looking contraption – on first impression more the outcome of a Jules Verne or H. G. Wells type of sketch rather than a tool of modern moon exploration. But the wheels were ideal for gripping the lunar surface and less prone to failure than caterpillars. The lid could be raised backward to the vertical and then flat behind, exposing solar cells to recharge the batteries in the Sun’s rays. The exposed top of the car was a radiator, discharging its electronic and solar-baked heat. There was genius in its simplicity.

The most dangerous part of the vehicle’s journey was probably getting off the platform and onto the lunar surface. Two ramps unfolded at each end, so it could travel down either way if one exit were blocked. Still sitting on the landing platform, ground control commanded the dust hoods to fall off the television eyes. A picture came back at once, showing the wheel rims, the ramp down to the flat bright surface and the silhouette of the landing ramps. There was nothing for it but to signal to Lunokhod to go into first gear and roll down the ramp and hope for the best.

So it was that at 6:47 a. m. on the morning of 17th November 1970, carrying the hammer and sickle, a red flag and a portrait of Lenin, the moon vehicle edged its way down the ramp and rumbled 20 m across the lunar surface. Its tracks were the first wheel marks made on another world. Its television cameras showed its every move and at one stage Lunokhod slewed around to film the descent stage which had brought it there. On day 2 it parked itself, not moving at all, lying there so that its lid could soak

in solar energy for its batteries. On day 3 it travelled 90 m, 100 m the following day, overcoming a 10° hill. On the fifth day, with lunar night not long off, it closed its lid, settled down 197 m from Luna 17 and shut down its systems for the 14-day lunar night. At this stage, it had travelled a modest 200 m. A nuclear power source would supply enough heat to keep it going till lunar daybreak.

The Soviet – and Western – press took to Lunokhod with an affection normally reserved only for friendly robot television personalities. There was unrestrained ad­miration for the technical achievement involved, for it was a sophisticated automated exploring machine. The Times of London called it ‘a remarkable achievement’. ‘A major triumph,’ said The Scotsman. The Daily Mail, in a front-page editorial entitled ‘Progress on wheels’ gave Lunokhod’s designers an effusive message of congratulations. It was the main news story for several days.

The control centre for Lunokhod was, like much else in the venture, a scene straight from science fiction. It was located in Simferopol, Crimea, near the big receiving dishes. Five controllers sat in front of television consoles where lunar landscapes were projected on screens. The crew of five worked together like a crew operating a military tank. Signals were relayed to the drivers by the high-gain antenna which had to be locked on Earth continuously. The drivers operated Lunokhod with a control stick with four positions (forward, backward, stop, rotate), and they could make the rover go either of two speeds forward: 800m/hr or 2km/hr, or reverse. If the Lunokhod looked like crashing, either drivers or commanders could press a panic button to turn the electric engine off. Any one wheel could be disconnected individ­ually if it got stuck or there were a problem. Lunokhod was designed to cope with obstacles up to 40 cm high or 60 cm wide, but an automatic system would cut the engine out if it began to tilt. Average speed started at 2.3 m/hr but later increased to 4.8 m/hr. All the wheels ran at the same speed and they turned the rover like a tank by running the wheels faster on one side than the other, until the change of direction was achieved – skid-steering [5]. In reality, driving the Lunokhod proved to be quite a lot more difficult than the drivers expected. The drivers realized at once that the cameras were too low down – it was like being a human on all fours rather than upright. The television cameras were able to provide little contrast: the images were too white, and rocks and craters looked deceptively alike [6]. Driving the moonrover was strenuous and during the lunar days the teams alternated 9 hr shifts, catching up on sleep during the lunar nights.

So great was the excitement of the first Lunokhod that journalists, academicians and scientists flooded into mission control, apparently taking up a general invitation to do so by Mstislav Keldysh. Vistors were not supposed to crowd around the drivers, still less talk. But the situation got out of hand, especially when backseat drivers would exclaim: ‘He’s going to crash into that rock!’ or ‘Mind that crater!’ Between the natural stress, the heat coming out of the televisions and the backseat drivers, the drivers’ pulses crept up to 140 and the stress began to tell. Babakin had had enough. ‘Everyone out of here!’ he ordered and after that special passes were needed to visit the control room and then in a suitable state of humility [7].

Back on the moon, nighttime temperatures plunged to — 150°C and stayed at that level a full two weeks. Lunokhod, lid closed, glowing warmly from the heat of its own nuclear radio isotope, rested silently on the Sea of Rains. It was bathed in the ghostly blue light of Earth as the mother planet waxed and waned overhead. Even as it stood there, laser signals were flashed to Lunokhod from the French observatory in the Pic du Midi and from the Semeis Observatory in the Crimea. They struck the 14 cubes of the vehicle’s laser reflector and bounced back. As a result, scientists could measure the exact distance from the Earth to the moon to within 18 cm.

To the east of Lunokhod rose a ridge and the sharp rays of dawn crept slowly over its rugged rocks early on 9th December. Had the moonrover survived its two-week hibernation? This was an anxious moment and pulses began to race when the first command was sent to the Sea of Rains to open the lid. Nothing happened. They tried again and this time the rover responded. It raised its leaf-shaped lid and at once began to hum with life. Four panoramic cameras at once sent back striking vistas of the moonscape, full of long shadows as the Sun gradually rose in the sky. After a day recharging, Lunokhod set out once more. The Lunokhod got into big trouble straight

away. On 10th December, Lunokhod got stuck in a crater and no matter what the drivers did – go forward, go back – it remained stuck. Eventually, after nine exhaust­ing hours, the rover suddenly came free.

The drivers on Earth soon got into their stride and they had the moon car in second gear, swivelling around, reversing and traversing craters and slopes at will. One day it travelled 300 m, more than it had achieved in its first five days in November. Lunokhod took a south-southeast path, skirting around and between craters and parked in December in a crater at the southernmost end of the route, 1,400 m from the landing stage. In January, swivelling round to head back north, the panoramic camera eyes spotted in the distance a range of mountains – the far peaks of the Heraclides Promontory, part of the vast bay encircling the Sea of Rains.

For ground control it was just like being there. From the cosy warmth of their control post they could direct at will a machine a quarter of a million miles away. This prompted romantic notions in the minds of the Earthbound. Radio Moscow promised ‘more Lunokhods, faster and with a wider range.’ Boris Petrov spoke of mooncars

that would collect samples and bring them to craft like Luna 16 for transporting home. Others would instal packages on the moon and carry telescopes to the farside where there was radio peace, free from Earthside interference. Other probes would reach the lunar poles.

It turned out that the drivers had been well selected for their mission. The drivers faced several challenges. First, the 20 sec frame transmissions were too slow. Although driving the lunar rover might seem simple enough to a modern generation reared on video games, in reality the crew had to memorize features some distance ahead. The 20 sec time gap between frames meant that Lunokhod could reach a feature – stone, rock, crater, obstacle – a full third of a minute before the crew saw visually that it had arrived. Second, the cameras were set in an awkward place: too low to see far ahead, yet set toward the horizon in such a way as to create a dead zone immediately in front of the rover that the drivers could not see. Third, the light contrasts of the lunar surface made driving difficult, the drivers having to cope with extremes of shadows and glare. Rather than risk driving across shadowless moonscapes, operations were normally halted for two days at lunar high noon. From time to time, Lunokhod would

stop to take panoramic pictures. For the drivers, these were good opportunities to orientate the rover and plan the next stage of the journey.