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Solar Wind Composition

NSSDCA ID: 1971-063C-11

Mission Name: Apollo 15 Lunar Module /ALSEP
Principal Investigator:Prof. Johannes Geiss


The solar wind composition (SWC) experiment was designed to determine the elemental and isotopic composition of the noble gases and other selected elements in the solar wind by measuring particles trapped on an aluminum foil sheet. These measurements were intended to help resolve competitive theories in the field of elemental synthesis, and to aid in understanding the origin of the solar system, the history of planetary atmospheres, and solar wind dynamics. The SWC experiment detector consisted of an expanse of foil unrolled from a reel so as to face the sun when placed on the lunar surface by the Apollo astronauts. The experiment was deployed by an Apollo 15 crewman during the first EVA, and retrieved during the last EVA. During the Apollo 15 lunar stay, and exposure time of 41 hrs was obtained for the SWC experiment. This amount of exposure probably lead to more detailed and more accurate solar wind abundance measurements than were possible with the shorter exposures obtained on Apollo 12 and 14.

Alternate Names

  • Apollo15ALSEP/SolarWindComposition
  • S080

Funding Agency

  • NASA-Office of Manned Space Flight (United States)


  • Planetary Science: Fields and Particles
  • Space Physics: Heliospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Prof. Johannes GeissPrincipal InvestigatorUniversitat
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