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Multispectral Scanner (MSS)

NSSDCA ID: 1978-026A-02

Mission Name: Landsat 3
Principal Investigator:Dr. Stanley C. Freden

Description

The LANDSAT 3 Multispectral Scanner (MSS) provided repetitive day/night acquisition of high-resolution multispectral data on the earth's surface on a global basis. While its primary function was to obtain data in various areas such as agriculture, forestry, geology, and hydrology, the MSS system was also used for oceanographic and meteorological purposes, i.e., to map sea-ice fields, locate and track major ocean currents, monitor both air and water pollution, determine snow cover, investigate severe storm environments, etc. The MSS consisted of a double reflector-type telescope, scanning mirror, filters, detectors, and associated electronics. The scanner operated in the following spectral intervals: (1) 0.5 to 0.6 micrometer, (2) 0.6 to 0.7 micrometer, (3) 0.7 to 0.8 micrometer, (4) 0.8 to 1.1 micrometers, and (5) 10.4 to 12.6 micrometers (these bands were designated as bands 4, 5, 6, 7, and 8, respectively). The last band, which lies in the thermal (emissive) part of the spectrum, gave LANDSAT 3 nighttime sensing capabilities. But this thermal band failed on July 11, 1978, and produced little useful data. Incoming radiation was collected by the scanning mirror, which oscillated 2.89 deg to either side of nadir and scanned cross-track swaths 185 km wide. The along-track scan was produced by the orbital motion of the spacecraft. The primary image produced at the image plane was relayed by use of fiber-optic bundles to detectors where conversion to an electronic signal was accomplished. Optical filters were used to produce the desired spectral separation. Six detectors were employed in each of the first four spectral bands and two in the fifth band: bands 4 through 6 used photomultiplier tubes as detectors, band 7 used silicon photodiodes, and band 8 used mercury-cadmium-telluride detectors. The minimum dimensions that were resolved by the MSS were 80 m for bands 4 through 7 and 240 m for band 8. A multiplexer included in the MSS system processed the scanner's 26 channels of data. These data were time-multiplexed and then converted to a PCM signal by an A/D converter. The data were transmitted (at 2229.5 MHz) directly to an acquisition station or stored on magnetic tape for subsequent playback the next time the spacecraft came within communication range of an acquisition station. Data from this experiment were handled by the NASA Data Processing Facility, GSFC, Greenbelt, Md., and were made available to approved investigators through its LANDSAT users' services. All other interested individuals can obtain data through the EROS Data Center, Department of Commerce, Sioux Falls, S.D.

Alternate Names

  • Landsat3/MSS
  • MSS

Funding Agency

  • NASA-Office of Space and Terrestrial Applications United States

Discipline

  • Earth Science: Land Surface Processes

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Stanley C. FredenPrincipal InvestigatorNASA Goddard Space Flight Center
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