Synonymous Platform Names:
LEO > Low Earth Orbit > Polar Sun-Synchronous
Related Data Sets
There are no related records to this platform.
[Source: National Space Science Data Center, https://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1976-091A
DMSP-5D-1/F1 was one of a series of meteorological satellites developed and operated ... by the Air Force under the Defense Meteorological Satellite Program (DMSP). This program, previously known as DAAP (Data Acquisition and Processing Program), was classified until March 1973. The objectives of this program were to provide global visual and infrared cloud cover data and specialized environmental data to support Department of Defense requirements. Operationally, the program consisted of two satellites in planned 83-km sun-synchronous polar orbits, with the ascending node of one satellite in early morning and the other at local noon. The 5.4-m-long spacecraft was separated into four sections: (1) a precision mounting platform (PMP) for sensors and equipment requiring precise alignment, (2) an equipment support module (ESM) containing the electronics, reaction wheels, and some meteorological sensors, (3) a reaction control equipment (RCE) support structure (that has the third-stage motor, hydrazine reaction control system) which supports (4) a 9.29 sq m solar cell panel. The Block 5D spacecraft stabilization was controlled by a conbination flywheel and magnetic control coil system so sensors could be maintained in the desired 'earth-looking' mode. One feature of Block 5D was the precision-pointing accuracy of the primary imager to 0.01 deg provided by a star sensor and an updated ephemeris navigation system. This allowed automatic geographical mapping of the digital imagery to the nearest picture element. The operational line scan system (OLS) built by Westinghouse, was the primary acquisition system that provided real-time or stored, multi-orbit, day-and-night visual and infrared imagery at 1/3 nautical mile resolution for all major land masses, 1-1/2 nautical mile resolution for complete global coverage, and provided with this data calibration, timing, and other auxiliary signals to the spacecraft for digital transmission to the ground. A supplementary sensor package, the special sensor H (SSH), a step-scanning radiometer, was the infrared temperature-humidity-ozone sounder. The data processing system, which included three high-density tape recorders, could store a total of 400 min of data, each allowing full global coverage twice daily. Either recorded or real-time data were transmitted to ground-receiving sites via two redundant s-band transmitters. Recorded data were read out to tracking sites located at Fairchild AFB, WA, and Loring AFB, ME, and relayed via SATCOM to Air Force Global Weather Central, Offutt AFB, NE. Real-time data were read out at mobile tactical sites located around the world. A more complete description of the Block 5D satellite can be found in the report, 'The Defense Meteorological Satellite Program,' D. A. Nichols, Optical Engineering, 14, 4, July - August 1975.
Vandenberg Air Force Base, USA
Department of Defense-Department of the Air Force (United States)