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The COS-B scientific satellite was developed by the European Space Agency (ESA) to study extraterrestrial gamma radiation in the 25-MeV to 1-GeV energy range from a highly elliptical orbit of roughly 100,000-km apogee, 350-km perigee, and near-polar inclination. NASA provided, on a fully reimbursable basis, the Delta launch vehicle and the associated launch services. The COS-B spacecraft was cylindrical with a diameter of 140 cm and a height of 121 cm. Four monopole antennas, protruding 51.2 cm below the bottom of the cylindrical body, gave the spacecraft a total effective height of 172.2 cm. The spacecraft obtained orientation of its angular momentum vector with respect to inertial space using data from an earth albedo sensor and a solar sensor. Spacecraft attitude was adjusted by a nitrogen cold-gas attitude control system (ACS). The ACS included two spin-rate-adjust nozzles to maintain the spin rate at 10 rpm and two precession nozzles to adjust the momentum vector. The spacecraft had a pcm/psk/pm telemetry system with 6.5-W real-time-only transmitter providing a switchable bit rate of 160 and 320 bps and a pcm/psk/pm, up-link/down-link, range-tone command system. Power was supplied by 9480 solar cells mounted on 12 subpanels on the cylindrical body of the spacecraft. Communications, command, and control of the COS-B satellite in orbit were provided by the ESA Estrack network. The spacecraft enclosed a gamma-ray astronomy experiment described under "COS-B Caravane Collaboration" below. Members of the university and research groups who implemented this satellite are listed, with their affiliations, in Appendix B.

Alternate Names

  • 08062
  • Cosmic Ray Satellite-B
  • PL-741B

Facts in Brief

Launch Date: 1975-08-09
Launch Vehicle: Delta
Launch Site: Vandenberg AFB, United States
Mass: 277.5 kg

Funding Agency

  • European Space Agency (International)


  • Astronomy

Additional Information

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



NameRoleOriginal AffiliationE-mail
Dr. Brian G. TaylorGeneral ContactESA-European Space Research and Technology Centre
Dr. Kevin BennettProject ScientistESA-European Space Research and Technology
Mr. G. AltmannProject ManagerESA-European Space Research and Technology Centre

US Active Archive for COS-B Information/Data

The COS-B Archive at HEASARC

Other Sources of COS-B Information/Data


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