THE LUNAR ORBITER CAMERA

From NSSDC Lunar Orbiter photograph support data

     
    This experiment consisted of a
  dual-lens camera system
  designed to satisfy the primary
  mission objective of providing
  photographic information for the
  evaluation of Apollo and Surveyor
  landing sites. An 80-mm lens
  system was used to obtain
  Medium-Resolution (MR) photos,
  and a 610-mm lens system was
  used for High-Resolution (HR)
  photos. The two separate lens,
  shutter, and platen systems
  utilized the same film supply and
  recorded imagery simultaneously
  in adjacent areas on 70-mm film.

  Automatic sequences of 1, 4, 8, or 16 photos could be obtained. At an altitude of 46 km, which was approximately the perilune height, the HR system photographed a 4.15- by 16.6-km area of the lunar surface which was centered on a 31.6- by 37.4-km area photographed by the MR system. Resolutions were 1 and 8 m, respectively. At apolune, on the moon's farside at about 1850-km altitude, the areas photographed were correspondingly larger.

  The film was bimat processed on board and optically scanned, and the resulting video signal was telemetered to ground stations. Film density readout was accomplished by a high-intensity light beam focused to a 6.5-micron-diameter spot on the spacecraft film. The spot scanner swept 2.67 mm in the long dimension of the spacecraft film. This process was repeated 286 times for each millimeter of film scanned. The raster was composed of 2.67- by 65-mm scan lines along the film.

   The video signal received at the ground station was recorded on magnetic tape and also fed to Ground Reconstruction Equipment (GRE), which reproduced the portion of the image contained in one raster on a 35-mm film positive framelet. Over 26 framelets were required for a complete MR photograph and 86 for a complete HR image.

   A detailed description of the experiment, a bibliography, and indexes of all the available Lunar Orbiter 1 through 5 photos are contained in the report 'Lunar Orbiter Photographic Data,' NSSDC 69-05, June 1969.

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