Apollo 12 Mission
Apollo 12 represented man's second opportunity to directly observe scientific phenomena on the lunar surface. Both the surface and orbital photography of the mission served not only to document man's second lunar landing and extravehicular activities of the astronauts, but also to identify scientifc areas and experiments for study in future missions. The photographic equipment and materials carried by Apollo 12 were designed specifically to (1) photograph targets of opportunity, i.e. scientifically interesting sites and potential Apollo landing sites as time and circumstances permitted; (2) obtain photographs of the lunar module and lunar surface activities after LM landing; (3) obtain multispectral, vertical, and oblique stereo strips of nearside and farside regions of scientific interest; (4) record mission operational activities; (5) obtain documentation for subsequent landing crew training purposes; and (6) obtain photographic information to document the geologic samples.
The Camera Equipment
The camera equipment carried by Apollo 12 consisted of one 70-millimeter Hasselblad EL camera, two Hasselblad data cameras, two 16-millimeter Maurer data acquisition cameras, one 35-millimeter lunar surface close-up stereoscopic camera, and a four-camera, multispectral S-158 experiment.
70-millimeter Hasselblad EL Camera. This camera, which was carried aboard the command module, featured a motor-drive mechanism, powered by two nickel-cadmium batteries that advanced the film and cocked the shutter whenever the camera was activated.
70-millimeter Hasselblad Data Cameras. The two electrically powered data cameras that were carried on the lunar module featured semiautomatic operation. They used a 60-millimeter Biogon lens exclusively. The operating sequence was initiated by squeezing a trigger mounted on the camera handle. A 1-centimeter reseau grid was set in front of the image plane to provide photogrammetric information in the analysis of the photography. The cameras were bracket-mounted on the front of the LM astronauts' EVA suits.
16-millimeter Maurer Data Acquisition Camera. Apollo 12 carried two Maurer data acquisition cameras (DAC), one in the command module and one in the lunar module. The cameras were used primarily to record engineering data and for continuous-sequence terrain photography. The CM camera had lenses of 50-, 10-, 18-, and 75-millimeter focal lengths; the LM camera was fitted with a 10-millimeter wide-angle lens. Accessories included a right-angled mirror, a power cable, a sextant adapter, a right-angled adapter, and a CM boresight window bracket.
The Maurer cameras weighed 2.8 pounds each, with a 130-foot film magazine attached. They had frame rates of 1, 6, and 12 fps automatic and 24 fps semiautomatic at all lens focal lengths, and shutter speeds of 1/60, 1/125, 1/250, 1/500, and 1/1000 second, also at all lens focal lengths.
35-mm Lunar Surface Close-up Stereoscopic Camera. This camera, which was carried on the lunar module's Modular Equipment Storage Assembly (MESA), was designed for the highest possible resolution for a stereo pair area with a flash illumination and fixed distance. Photography was accomplished by holding the camera on a walking stick against the object to be photographed. The camera was powered by four nickel-cadmium batteries that operated the motor drive mechanism and an electronic flash strobe light.
Four-Camera, Lunar Multispectral S-158 Experiment. The lunar multispectral camera (LMC) experiment used four Hasselblad EL cameras. The objectives of the experiment were (1) to photograph lunar surface color variations for geologic mapping, (2) to correlate photographs with spectral reflectance of returned samples for compositon determination, (3) to photograph potential lunar landing sties, and (4) to make comparative studies of lunar reflectance variation and wavelengths. (A similar experiment was flown as the SO-65 Earth multispectral photography experiment on Apollo 9.)
The four cameras used had the same parameters, settings, and ranges as the Hasselblad EL camera with the 80-millimeter lens. The cameras were mounted in a ring bracket perpendicular to the command module hatch window ±5° from nadir, 57.5° pitched up from the X axis. The shutters were automatically tripped by an intervalometer at 20-second intervals to obtain vertical strip photography.
An important photographic objective was to obtain, from lunar orbit, photographs of future landing sites. Orbital photographs did aid in the planning of pinpoint landings in lunar terrain more rugged and of even greater scientific interest than the mare-type terrain at the Apollo 11 and 12 landing sites. Extensive landmark tracking and photography were performed in lunar orbit. The lunar orbit photogrpahy was conducted using a 500-millimeter long-range lens to obtain mapping and training data for future missions.
Lunar Surface Photography
Following touchdown, photographs of the immediate vicinity of the Lunar Module were taken through the LM windows. Shortly after both astronauts egressed the LM, the television camera was inadvertently pointed directly at the Sun, and television coverage of the mission was lost. Thus, the photographs taken by the crew are the only visual record of their (1) surface activities, (2) sample documentation, and (3) stereoscopic surface photography. Both crewmen took hundreds of photographs while on the surface.
Surface Activities. The lunar terrain over which the lunar module traveled during descent was documented by the 16-mm sequence camera. The 70-mm film exposed on the surface, when not affected by sun glint on the lens or surface washout by sunlight, was generally of good quality.
Crew activities and lunar surface features near the lunar module, the experiment package, and those observed during the two extravehicular excursions were well documented by still-camera short sequences and by a number of panoramic views.
Sample Documentation. In addition to collecting samples, one of the main scientific tasks to be accomplished during the extravehicular activities was photographing rocks, the lunar surface and the moonscape.
Stereoscopic Closeup Surface.To obtain information about in-place lunar rocks and soil, a close-up stereoscopic camera capable of photographing small-scale surface features was used at the Apollo 12 landing site. The camera was the same type as the one used during the Apollo 11 mission. Fifteen stereoscopic photograph pairs were obtained. The types of lunar surfaces photographed were (1) solid and rock surfaces not greatly disturbed by the LM descent engine exhaust, (2) soil surfaces disturbed by the LM descent engine exhaust, and (3) soil surfaces disturbed by astronaut boots.
The soil in the upper quarter of the area photographed was cohesive enough to form a vertical wall at the edge of the exhaust-gas disturbance and for a clump of it to slide over the surface without fragmenting (right center portion of the photograph). The photograph was possibly taken of an area in which the soil had been compressed by the LM footpad.
The scientific, geologic, and photographic objectives of the Apollo 12 mission were designed to achieve the maximum return of lunar data. The staytime on the lunar surface was increased to accommodate two extravehicular activity periods. The photography accomplished during the Apollo 12 mission documented and augmented the experimental, observational, and geologic data obtained from the extended lunar surface activities and from the scientific instruments placed on the lunar surface. A further photographic objective was to obtain, from lunar orbit, photographs of future landing sites.
During the mission, all but two of 25 70-millimeter and 16-millimeter film magazines carried on board were returned exposed. A partially exposed 70-millimeter magazine had jammed and was inadvertently left on the lunar surface, and one 16-millimeter magazine was not used. Approximately 53% of the suggested targets of opportunity from lunar orbit were photographed.