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Micrometeoroid Detector and Analyzer

NSSDCA ID: 1974-097A-12

Mission Name: Helios-A
Principal Investigator:Dr. Hugo Fechtig


The purpose of the experiment (E10) was to investigate some theories about the interplanetary dust including whether or not (1) the number of particles increases toward the sun, (2) the cutoff for small particles is dependent on the distance from the sun, because solar pressure increases nearer the sun, and (3) the number densities of particles change near the orbits of planets. The kinetic energy of dust particles hitting a target with high velocity (several km/s) caused the material to vaporize and become partially ionized. The generated plasma cloud was then separated by appropriate voltages into its negative (electron) part and into positive ions. The mass and the energy of the dust particles were determined from the impulse heights. A time-of-flight mass spectrometer in connection with the target allowed the small ion cloud to be analyzed. In this way, the investigation of the chemical composition of the dust particles became possible. The threshold for the detection of a particle was about 1.E-15 g. Mass and energy determination was possible for particles larger than about 1.E-14 g. For particles larger than 1.E-13 g, a mass spectrum was gathered. For further details, see pp. 268-269 of Raumfahrtforschung, v. 19, n. 5, 1975.

Alternate Names

  • Helios-A/MicrometeoroidDetectorandAnalyzer

Funding Agency

  • Bundesministerium fuer Wissenschaftliche Forschung (Federal Republic of Germany)


  • Space Physics: Zodiacal Light/Interplanet Dust
  • Planetary Science: Small Bodies

Additional Information

Questions and comments about this experiment can be directed to: Dr. H. Kent Hills



NameRoleOriginal AffiliationE-mail
Mr. J. WeihrauchOther InvestigatorMax-Planck-Institut fur Physik und Astrophysik
Dr. Hugo FechtigPrincipal InvestigatorMax-Planck-Institut fur Kernphysik
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