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Helium Abundance Detector (HAD)

NSSDCA ID: 1989-084E-01

Mission Name: Galileo Probe
Principal Investigator:Dr. Ulf Von Zahn


The objective of this investigation was the precise (0.1%) determination of the helium abundance in the Jovian atmosphere from 3-8 bars. A two-arm, double-pathlength optical interferometer that includes an infrared LED light source operating at a wavelength of 900 nm, an interference filter, and a photodetector array, is used to measure the refractive index difference between an atmospheric sample and a reference gas mixture. It was mounted on the probe with an inlet pipe to the ambient atmosphere.

Alternate Names

  • GalileoProbe/HAD
  • HAD
  • urn:nasa:pds:context:instrument:gp.had

Facts in Brief

Mass: 1.4 kg
Power (avg): 0.9 W
Bit rate (avg): 0.004 kbps


  • Planetary Science: Atmospheres

Additional Information

Questions and comments about this experiment can be directed to: Dr. Edwin V. Bell, II



NameRoleOriginal AffiliationE-mail
Prof. Donald M. HuntenCo-InvestigatorUniversity of
Dr. H. J. HoffmanCo-InvestigatorMesserschmit-Bolk-Blom
Dr. Ulf Von ZahnGeneral ContactUniversitat
Dr. Ulf Von ZahnPrincipal InvestigatorUniversitat

Selected References

  • von Zahn, U., and D. M. Hunten, The Jupiter helium interferometer experiment on the Galileo entry probe, Space Sci. Rev., 60, No. 1/4, 263-281, doi:10.1007/BF00216857, May 1992.
  • von Zahn, U., and D. M. Hunten, The helium mass fraction in Jupiter's atmosphere, Science, 272, No. 5263, 849-851, doi:10.1126/science.272.5263.849, May 1996.
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