NSSDCA ID: 1973-049A-05
Mission Name: Mars 5The Mars 5 imaging system consisted of two Phototelevision Units (PTU) for wide-angle and narrow angle images, and a panoramic imager. The PTUs were fixed within a hermetic bay of the station and were parallel to each other in the orbital plane of the satellite. Pointing was achieved by positioning the spacecraft. Each PTU held a reel of photographic film and a film developing and fixing/drying apparatus. The exposed and developed film image was facsimile scanned at 220 x 235, 880 x 940, or 1760 x 1880 pixels and transmitted to Earth by a television system at 6 kbps. The frame size on both cameras was given as 23 x 22.5 mm, but judging from the scan dimensions it is probably 22 x 23.5 mm.
The first imager, PTU-1, had a Vega-3MSA objective with a focal length of 52 mm and a relative aperture of f/2.8. The field-of-view was 35.7 degrees, with a resolution of approximately 735 m at 2000 km altitude. It was equipped with a revolving mechanism holding red, green, blue, and orange filters which could be selected by ground command. The PTU-2 imager used a Zufar-2SA objective with a 350 mm focal length and a relative aperture of f/4.5. The field of view was 5.67 degrees with a resolution of 110 m at 2000 km altitude. It was fitted with an orange filter. Exposures could be 1/50 or 1/150 second. 20 meters of film were carried onboard
The panoramic imager was an optico-mechanical single-line scanning photoelectric photometer with a 30 degree field of view for panoramic images in the visible and near-infrared. It used a mirror to create a horizon-to-horizon image at 4 lines per second, at up to 512 pixels per scan line. It took 90 minutes to create one panorama.
In most images, the solar elevation over the local horizon was 15-35 degrees, the maximum elevation of the station close to 90 degrees, with a constant phase angle of 65 degrees. Approximately 12 pictures taken per periapsis pass, the main sessions being February 17, 21, 23, 25, and 26. 108 photographs were taken by the PTUs, 43 of the images were of good quality, and five panoramic images were returned covering 5 N to 20 S, 130 W to 330 W. Several images showed traces of water erosion on the surface.
Questions and comments about this experiment can be directed to: Dr. David R. Williams
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