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OV1-18 was one of four research satellites injected into orbit simultaneously from a single launch vehicle. The spacecraft was an 81-cm-long cylinder measuring 69 cm in diameter and was fitted with hemispheric multifaced solar panel domes on each end. Proper satellite orientation was maintained through a gravity gradient stabilization system consisting of three horizontal booms, 15.5 m long and forming a 'y', and two 19-m-long vertical booms. The satellite was also fitted with a large disc-shaped RFI antenna. OV1-18 carried a variety of experiments to make a detailed study of the characteristics of the ionosphere as they affect radio wave propagation, especially the causes of anomalous or unusual effects on the communication, detection, control, and tracking systems. The spacecraft was also fitted with experiments to gather information on the horizontal ion density gradients, electric fields, and gamma rays. The gravity gradient booms failed to deploy properly after launch. The resulting spacecraft instability reduced the applicability of data from many of the experiments. OV1-18 was placed operationally off in August 1970. The spacecraft reentered the earth's atmosphere on March 5, 1971.

Alternate Names

  • 03824
  • 1969-025B

Facts in Brief

Launch Date: 1969-03-18
Launch Vehicle: Atlas
Launch Site: Vandenberg AFB, United States
Mass: 125 kg

Funding Agency

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


  • Space Physics
  • Astronomy

Additional Information

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



NameRoleOriginal AffiliationE-mail
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