Phototelevision Cameras

The first cameras in space used photographic film, which was automatically developed and scanned for transmission to Earth. This seems mechanically complex, but in the context of 1959 technology, this approach had several advantages. Film could rapidly capture an image, far beyond the resolution and sensitivity of vidicon television tubes. An enormous amount of visual information could be stored on a roll of film. The images could then be repeatedly rewound and scanned at whatever rate was convenient for telemetry transmission. The American Lunar Orbiter missions adopted the same strategy six years later.
The Enisei camera system was developed at the Leningrad Scientific Research Institute of Television (NII-380) by P.F. Bratslavets and others. Adjacent frame pairs were simultaneously exposed, through 500 mm and 200 mm objective lenses, onto 35 mm aerial-reconnaissance film (obtained from American spy balloons, according to one Russian account). The system cycled through four exposure times, 1/200 to 1/800 sec, as it photographed the Moon.

After photography, the film was automatically developed, fixed and dried in chambers of chemicals, and then scanned by a flying spot CRT and a photomultiplier tube. It could scan the film slowly at 1000 pixels per line resolution and 1.25 lines per second, or rapidly at 50 lines per second, during its return orbit to Earth.

The radio system was developed by E.Ia. Boguslavskii, at the Research Institute for Space Device Engineering (RNII-KP). He championed the use of impulse transmitters, which later enabled remarkable telemetry rates from planetary distances. However, on Luna-3, Boguslavskii surprised his colleagues by constructing a continuous-carrier FM video transmitter, operating on 183.6 MHz.

On October 7, 1959, Man's first view of the far side of the Moon was returned by Luna-3. A pair of frames at correct relative size, show typical 500 mm and 200 mm views. Locked in 3-axis stabilization, the spacescraft spent 40 minutes photographing the Moon, then resumed spin stabilization. The camera held 40 frames, and frames 26 to 38 were definately received and recorded in full resolution. Some reports claim 17 frames were recorded. Six frames have been published. The mission was timed to photograph the fully illuminated Moon, but this angle of light meant low terrain contrast.
The periodic bands of static seen in the frames above were due to spacecraft spin and dead spots in its antenna's radiation pattern. Temporary receivers were set up in the Crimea and Kamchatka, with magnetic tape, 35mm film recording and instant thermal-paper recording devices. The high-gain telemetry receiving stations in Simferopol and Evpatoriia were not completed in time for Luna-3's flight. Photographs were made from the magnetic tape recordings, at varying amplifications, to study the full range of signal contrasts.

The Mars probe, 1M, was designed to carried an identical or very similar camera in 1960. Image transmission was on 3.7 GHz, the continuous-carrier Pluton telemetry signal, it probably did not contain an impulse transmitter. The camera was later removed to save weight, after the optimum-energy launch window was missed. Both 1M probes were subsequently destroyed by rocket failures.

Mars-1, in 1962, contained a complex 32-kilogram camera. It contained both 35 and 750 mm lenses and used 70 mm film. It alternately shot square images and larger 3×1 rectangular images. It had a capacity of 112 pictures on a roll of film, and these could be scanned at 1440, 720 lines or 68 lines for rapid preview. Individual frames could be rescanned and transmitted later, by telecommand. The camera system may have been built by Bratslavets, but after this time, deep-space camera systems were constructed in the Research Institute of Space Device Engineering.
The camera is also reported to have contained an ultraviolet spectrograph. The UV spectrum was projected onto the film next to the picture. A 3-4 micron infrared diffraction spectrometer was also onboard and oriented parallel to the axis of the camera. Both the UV and IR spectrometers were designed by A.I. Lebedinskii.

The camera contained its own 6 GHz transmitter using pulse position modulation. The 50 watt transmitter worked by emitting 25,000 watt pulses of very short duration. This was before the invention of redundant coding systems, and high-power impulse transmission was an ingenious method for increasing data bandwidth over distances of 300 million kilometers. This system was probably built by Boguslavskii. Image were sent as discrete pixels, but gray levels were probably encoded as analog pulse position, not binary digital values. The high-quality transmission rate was 90 pixels per second, requiring about 6 hours to send a 1440×1440 image.

This camera was also carried by a similar spacecraft on an unpublicized 1962 photo-flyby mission to Venus. Radio contact with Mars-1 was lost at 106 million km, due to loss of attitude-control propellant. The Venus probe was stranded in parking orbit.

The 1965 Zond-3 mission returned 23 pictures (with orange filter) and an UV spectra of the far side of the Moon. A 106.4 mm objective lens was used on this camera. In addition, some test patterns were pre-exposed at the start and end of the film. Images were taken and developed every 2.25 minutes, with alternating 1/100 and 1/300 second exposures. A rapid 67 line/picture survey scan was first performed, and then commands were sent to rescan images at high resolution, with some resent several times. It continued on to a distance equivalent to Mars fly-by, rewinding the film and testing image transmission several times.

As before, a 5-centimeter-band impulse transmitter sent pixel values to Earth, or alternatively, an 8-centimeter-band continuous wave transmitter could send the results. Most likely, both systems were tested at various distances. In high-quality mode, images were sent at 550 pixels per second (2 seconds per scanline), requiring 34 minutes to send a 1100×110 image.

A 285-355 nm UV spectrograph was incorporated into the camera and recorded onto three frames of the film. A second, coaxial, UV spectrometer measured 190-275 with a photomultiplier detector and output digital telemetry. A coaxial 3-4 micron IR spectrometer was included on Mars missions, to investigate common organic molecular absorption bands, and a 6-40 micro IR spectrometer was included on Venus missions to investigate thermal balance. Spectrometers were designed by A.I. Lebedinskii and V.A. Krasnopol'skii.

Zond-2 may have carried two of these cameras with 200 and 500 mm lenses, but failed en route to Mars. Luna-12 carried two cameras of this design (one with a 500 mm lens) in a low-altitude lunar orbit in 1966. Luna-12 returned 40 images per camera at a doubled scanning speed. An identical mission on Luna-11 experienced a failure of its orientation system and photographed black space. Venera-2 carried one camera with a 200 mm lens to Venus, but the spacecraft failed before its final planetary-encounter telemetry playback.