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Asteroid/Meteoroid Astronomy

NSSDCA ID: 1973-019A-03

Mission Name: Pioneer 11
Principal Investigator:Dr. Robert K. Soberman


This experiment was designed to investigate asteroids and meteoroids in interplanetary space and in the vicinity of Jupiter and Saturn. Two types of data were collected. The first type consisted of measurements of individual particles passing through the field of view. The second type consisted of measurements of sky brightness. The instrumentation consisted of four identical non-imaging Ritchey-Chretien telescopes which detected particles by the reflection of light from them. The telescopes were mounted at angles of 45 deg with respect to the spacecraft's spin axis and provided with primary mirrors 20 cm in diameter having focal lengths of 20 cm. The full angular field of view of each telescope encompassed 7.5 deg. The telescopes were aligned so as to be approximately parallel to one another. Light reflected from asteroids and meteoroids was detected and amplified by means of S20 photocathodes and RCA 7151 Q photomultipliers. An event was recorded when at least three of the four telescopes saw the object. Entry and departure times of the light enabled determination of range and velocity. One of the four telescopes failed at 1.1 AU. Investigators are urged to use caution in interpreting the results of this experiment. This instrument failed in December 1974.

Alternate Names

  • AMD
  • Asteroid/Meteoroid Detector (AMD)
  • Pioneer11/AMD

Funding Agency

  • NASA-Office of Space Science (United States)


  • Planetary Science: Small Bodies
  • Astronomy: Visible

Additional Information

Questions and comments about this experiment can be directed to: Dr. John F. Cooper



NameRoleOriginal AffiliationE-mail
Dr. Herbert A. ZookOther InvestigatorNASA Johnson Space Center
Dr. Robert K. SobermanPrincipal InvestigatorGeneral Electric
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