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IMEWS 4 was the fourth in a series of first generation DSP program of Integrated Missile Early Warning Satellites manufactered by TRW for the US Air Force. The spacecraft spun slowly (6 rpm) about the nadir axis to permit scanning of the Earth by the detector system. Body mounted and deployable panels provided 400W of power.

Alternate Names

  • Early Warning 4
  • DSP F4
  • 06691
  • IMEWS4

Facts in Brief

Launch Date: 1973-06-12
Launch Vehicle: Titan III-C
Launch Site: Cape Canaveral, United States
Mass: 820 kg

Funding Agency

  • Department of Defense-Department of the Air Force (United States)


  • Surveillance and Other Military

Additional Information

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


Image courtesy of the USAF Defense Support Program.

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