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Imagers

NSSDCA ID: 1973-047A-05

Mission Name: Mars 4

Description

The Mars 4 imaging system consisted of two Phototelevision Units (PTU) for wide-angle and narrow angle images, and panoramic imagers. 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 imagers were optico-mechanical single-line scanning photoelectric photometers with a 30 degree field of view for panoramic images in the visible and near-infrared. They 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.

Alternate Names

    Funding Agency

    • Institut Kosmicheskich Issledovaniy(Inst. of Cosmophysical Research) U.S.S.R

    Discipline

    • Planetary Science: Geology and Geophysics

    Additional Information

    Questions and comments about this experiment can be directed to: Dr. David R. Williams

     

    Personnel

    NameRoleOriginal AffiliationE-mail

    Selected References

    • Florenskii, K. P., et al., Geological and morphological analysis of some Mars 4 and 5 photographs, Cosmic Res., 13, No. 1, 56-64, July 1975.
    • Selivanov, A. S., et al., Instrumentation and some photographic results obtained with Mars 4 and 5, Cosmic Res., 13, No. 1, 51-55, July 1975.
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