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2- to 10-KeV Sky Survey Instrument (SSI)

NSSDCA ID: 1974-077A-02

Mission Name: Ariel 5
Principal Investigator:Prof. Kenneth A. Pounds


This experiment consisted of a large-area proportional counter arranged to view in a direction perpendicular to the satellite spin axis. The satellite rotation, therefore, allowed a scan of a 360-deg band of the sky. When the satellite spin axis was arranged to point at a galactic pole, the whole of the Milky Way could be scanned at once. The experiment covered the photon energy range 1.5 to 20 keV and effected a high-sensitivity survey, obtaining source locations, intensity, and spectra. A number of different modes of operation were used in which the available storage space in the core stored obtained spatial information at the expense of spectral resolution, or the converse. The sensitivity of the experiment allowed the detection of sources of the order of 1.E-4 times the intensity of Sco X-1, within the time of about 1 day. The ability of the survey instruments to determine the position of a source depended on the strength of the source and the number of other sources in a given part of the sky. A source of 5E-3 times the strength of Sco X-1 could be located with a precision of about 15 arc-min.

Alternate Names

  • 2 - 10 KeV Sky Survey
  • Ariel5/SSI
  • SSI

Funding Agency

  • Unknown (United Kingdom)


  • Astronomy: None assigned

Additional Information

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



NameRoleOriginal AffiliationE-mail
Dr. Brin A. CookeOther InvestigatorUniversity of
Dr. David J. AdamsOther InvestigatorUniversity of
Dr. R. E. GriffithsOther InvestigatorUniversity of Leicester
Prof. Kenneth A. PoundsPrincipal InvestigatorUniversity of
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