No one on Earth had seen the far side of the Moon. For four and a half billion years, it had hidden half its face—and in October 1959, a group of engineers decided that developing photographic film in space was a sensible idea.
Konstantin Tsiolkovsky wrote about humanity’s cradle when rocketry was still a paper exercise. By the late fifties, the cradle was already cracking. The first satellite had been up for two years, Luna-2 had slammed into the lunar surface three weeks before the events described here—and that was considered a success, because hitting the Moon from 380,000 kilometers away is genuinely difficult. Now the task was not to crash, but to fly past, turn around, take photographs, and somehow get the images back. It sounded like a screenplay an editor would reject as implausible. But chief designer Sergei Korolev and the lunar program’s scientific director Mstislav Keldysh had one advantage: they did not ask editors.
The project was designated E-2A No. 1. The spacecraft weighed 278.5 kg—roughly as much as three adults. A pressurized cylinder 130 cm long and 95 cm in diameter, filled with nitrogen at 0.22 atmospheres—essentially a tin can with interplanetary ambitions. Inside that can they packed a camera, a chemical lab, a television scanner, an attitude-control system, batteries, and a radio transmitter. Outside—solar panels, bringing its diameter across to 120 cm. It launched from Baikonur on October 4, 1959, at 00:43:40 UTC, aboard a Luna 8K72 launch vehicle with a Blok-E upper stage. The date coincided with the second anniversary of the first satellite’s launch—coincidence or not, the Soviet space program loved such rhymes.
To photograph the far side of the Moon, you have to get behind it. The obvious solution—entering lunar orbit—was technically impossible: the probe had no braking engine. That left a trick no one had tried before: use the Moon’s gravity to bend the spacecraft’s trajectory and send it back to Earth. The first gravity-assist maneuver in history. The trajectory was calculated by Dmitry Okhotsimsky’s group at the Steklov Mathematical Institute, using the Strela-1 computer—a machine that occupied an entire room and ran on vacuum tubes. A computer the size of a garage plotted a course for a spacecraft the size of a barrel.
At 14:16 UTC on October 6, 1959, the probe passed its closest point—6200 km above the lunar surface, near the south pole. Gravity turned its trajectory, and Luna-3 began heading around to the far side, moving farther away. The photography was scheduled not for the moment of closest approach, but later—when the spacecraft had moved far enough away to capture a sufficiently large stretch of the surface in the frame. Roughly speaking, the photographer first walked right up to the subject, then took a few steps back so it would fit in the viewfinder. That required the spacecraft to point its camera precisely at the Moon—and it was flying while spinning like a thrown ball.
For most of the flight, the probe rotated around its axis—this is the simplest way to stabilize it; a spinning top holds its direction. But for photography, the rotation had to be stopped and the camera aimed. The Chaika attitude-control system was developed by Boris Rauschenbach, and it was an ingenious thing: three gyroscopes, Sun sensors, a separate lunar-light sensor, and eight compressed-nitrogen microthrusters. The tanks held gas at 150 atmospheres, a regulator reduced it to 4 atmospheres—and tiny nozzles delivered impulses, turning the spacecraft.
The pointing logic had two stages. First, the sensors found the Sun—a bright, unambiguous reference point. One axis was fixed using the Sun. Then the lunar-light sensor came into play, catching radiation reflected from the Moon and making the final adjustment to point the camera exactly at the target. It sounds simple, but in 1959, three-axis stabilization of a spacecraft was technology bordering on science fiction. Neither the Americans nor anyone else had done this in interplanetary space. The engineering audacity still amazes me: stabilizing a 278-kilogram barrel in a vacuum, hundreds of thousands of kilometers from any workshop, with jets of nitrogen and a photocell.
Starting at 03:30 UTC on October 7, the camera operated for 40 minutes. The distance to the lunar surface ranged from 63,500 to 66,700 km. It took 29 photographs, covering 70% of the far side.
Here is the detail that takes my breath away every time. The photographic film used to capture the far side of the Moon was American. Not bought, not acquired through diplomatic channels—salvaged from downed reconnaissance balloons from Project Genetrix. The Americans launched high-altitude balloons carrying cameras over Soviet territory, Soviet air defenses shot them down, and the film—isochromatic, type ASH-1, short for “American little balloon”—was carefully extracted and put into storage. The film turned out to be excellent: highly radiation-resistant, suitable for use in a vacuum, with good exposure latitude. Better than anything Soviet industry was producing at the time. The enemy’s spy film flew off to photograph the Moon—and try saying after that that history has no sense of humor.
The AFA-E1 camera was manufactured at the Krasnogorsk Mechanical Works. Two lenses: a 200 mm lens with an f/5.6 aperture for wide shots, and a 500 mm lens with f/9.5 for more detailed ones. The 40 frames of film were all the spacecraft had to work with. The exposed material—29 successful exposures—remained aboard as exposed but undeveloped emulsion. And here began the second half of the adventure.
Digital cameras did not exist. There was only one way to transmit an image to Earth: develop the film, dry it, shine a beam through it, and read the brightness point by point. All of it automatically, without a single human touch, inside a sealed container flying through space.
The Yenisey-2 photo-television system was created at Leningrad’s NII-380 under the direction of Pyotr Bratslavets. The principle was this: after exposure, the film was pulled through baths of developer, fixer, and rinse solution, then dried. The entire chemical cycle was single-use—there was no second attempt. If the solution temperature drifted by a few degrees, if the film jammed in the transport mechanism, if the drying proved incomplete—that was it. No backup plan. The engineers designing this system were essentially building an automatic photo lab that had to work exactly once, and exactly right.
After development and drying, the film was fed into a scanner. An 8LK2B cathode-ray oscilloscope tube formed a thin beam of light that passed line by line through the frame. On the other side of the film, an FEU-15 photomultiplier measured the amount of transmitted light—and converted it into an electrical signal. Resolution: 1000 lines per frame. The resulting video signal was transmitted at 183.6 MHz, with transmitter power of just 3 watts. Three watts—that is less than the bulb in a refrigerator. And this whisper had to cross the abyss of space to reach antennas on Earth.
Transmission could not begin immediately after the photography, and the reason was prosaic: geometry. While the spacecraft was behind the Moon or near it, Earth was either blocked by the lunar disk or at an unfavorable angle for the directional antenna. The probe was flying back toward Earth along an elongated loop, and the closer it came, the stronger the signal became at the receivers. Transmissions were received at tracking stations in Crimea and Kamchatka (the Yelizovo site). The first usable frames were received on October 18—eleven days after they were taken.
By that point, 17 photographs had been transmitted. Of those, six were selected for publication—frames No. 26, 28, 29, 31, 32, and 35. The rest were too grainy, overexposed, or distorted by interference. The connection was temperamental: the transmitter barely had enough power, atmospheric and ionospheric interference tore at the signal, and every repeated scan degraded the quality—the tube’s beam burned the emulsion. Honestly, it is astonishing that anything came through at all.
Six grainy, high-contrast, occasionally blurred photographs—and they overturned humanity’s idea of the Moon. The near side, which people had observed for millennia, is covered in vast dark patches—lunar seas, frozen basalt plains. The far side turned out to be different. There were almost no seas. The surface looked cratered, mountainous, pale—as if the two hemispheres of one body had lived different geological lives. This discrepancy is still explained in different ways: differences in crustal thickness, asymmetry in tidal heating, peculiarities of ancient impacts. There is still no single answer, more than sixty years later.
At the Sternberg State Astronomical Institute (GAISh), a group led by Yuri Lipsky compiled the first atlas of the Moon’s far side. The catalog included 500 objects. The largest dark formation was named Mare Moscoviense—the only full-fledged “sea” on the far side. One prominent crater was given the name Tsiolkovsky—the very man with the cradle. The photographs revealed mountain ranges, cirques, and depressions that no telescope could ever see in principle: the Moon faces Earth with only one side because of tidal locking, and no improvement in optics can change that. You had to physically fly behind it.
Contact with Luna-3 was lost on October 22, 1959. The spacecraft continued flying in a highly elongated elliptical orbit around Earth—silent, with burned-out film and empty nitrogen tanks. It completed 11 orbits, and another unexpected scientific result emerged: the probe’s orbit became the first observed example of the Lidov–Kozai effect. Gravitational perturbations from the Moon and the Sun gradually altered the shape of the orbit, driving swings in its inclination and eccentricity. In April 1960, the spacecraft entered Earth’s atmosphere and burned up.
The mission cannot be called flawless. Some of the photographs proved unusable. The probe did not complete all its planned operations. The signal was so weak that receiving stations worked at the limits of their sensitivity. And yet—a barrel-sized cylinder packed with spy film and developing baths flew behind the Moon, turned around, photographed what no human being had seen in the entire history of the species, developed the pictures in zero gravity, and sent them home on the power of a desk lamp. Of the 29 frames, six survived, but those six turned the unseen hemisphere from a philosophical abstraction into a map with names. Mare Moscoviense and Tsiolkovsky crater appeared on it not because someone had perfectly calculated every step, but because several hundred engineers decided that “impossible” was a working problem with poorly defined boundary conditions.