NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header




The cylindrically shaped Block 4 satellites incorporated two new one-inch diameter vidicon cameras, video (2), a large capacity tape recorder, and an all-digital command subsystem with magnetic core memory, giving fully programmable coverage of either direct readout or readout of recorded data without interference. Nominal satellite spin rate was decreased to reduce smear, permitting a higher resolution TV system for improved picture quality. Dual cameras and a high capacity recorder provided complete daily coverage of the entire northern hemisphere and tactical coverage anywhere on the earth. The Defense Meteorological Satellite Program's Block 4 space segment consisted of satellites in 450 nautical mile sun-synchronous polar orbits each carrying a payload of meteorological sensors. Primary cloud imaging sensors capable of globally viewing the earth in the visible and infrared spectrums were carried by every satellite. The ascending node of the satellites were either in the early morning time period or at mid-day. The final data product was a film product directly usable for imagery analysis. Originally part of a classified system of USAF weather satellites, the spacecraft mission was not revealed until March 1973.

Alternate Names

  • DMSP 2418
  • 02669
  • DMSP4A/F2

Facts in Brief

Launch Date: 1967-02-08
Launch Vehicle: Thor
Launch Site: Vandenberg AFB, United States
Mass: 150 kg

Funding Agency

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


  • Earth Science

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. Dieter K. Bilitza



NameRoleOriginal AffiliationE-mail
Project ManagerUS Air Force Space Division
[] NASA Logo -