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This French spacecraft had a 26-face polyhedron shape with a diameter of 80 cm. The primary mission objective was to study the upper atmosphere density variations. Secondary objectives included a study of gravity field perturbations and a study of micrometeorite impacts. A three-axis magnetometer was used to provide attitude information. Each one of the spacecraft faces contained a laser reflector. Data were measured either every 0.1 s or every 2.8 s. The data transmission rate was 1024 bits/s from the tape recorder and either 256 or 512 bits/s directly from telemetry. Operations were conducted by the operations center in Toulouse using the CNES network of telemetry and telecommand stations.

Alternate Names

  • Castor
  • 07802

Facts in Brief

Launch Date: 1975-05-17
Launch Vehicle: Diamant
Launch Site: Kourou, French Guiana
Mass: 76 kg

Funding Agency

  • Centre National d'Etudes Spatiales (France)


  • Planetary Science
  • Earth Science

Additional Information

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



NameRoleOriginal AffiliationE-mail
Mr. J. P. ChassaingGeneral ContactCentre National d'Etudes Spatiales
Dr. Francois E. BarlierProject ScientistCentre d'Etudes et de Recherche Geodynamiques er
Mr. A. OliveroProject ManagerCentre National d'Etudes Spatiales
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