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Rigid Sphere 2



This satellite (RID 701) was a 1.11-m-diameter rigid aluminum sphere. It was one of seven spherical research satellites that were ejected from OV1-21. The spacecraft served as a radar calibration target with a cross section of 1 m.

Alternate Names

  • RTD-701
  • Lincoln Labs Calibration Sphere
  • 05398
  • SESP 70-2J
  • RigidSphere2

Facts in Brief

Launch Date: 1971-08-07
Launch Vehicle: Atlas
Launch Site: Vandenberg AFB, United States
Mass: 34 kg

Funding Agency

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


  • Engineering
  • Earth Science

Additional Information

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

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