Solar Wind Composition Experiment

Aldrin aligning the Bern solar wind sail (Photo: Apollo 11, NASA image AS11-40-5872)

The Solar Wind Composition (SWC) experiment was the only non-American experiment on the Apollo 11 mission . Particles of the solar wind were captured in an exposed aluminum foil and analyzed in the laboratory after returning from the moon . The target with a size of 1.40 meters by 0.3 meters is known as the solar wind sail and was stuck in the bottom of the moon by astronaut Buzz Aldrin on July 21, 1969 , before the American flag, in order not to waste valuable time for this experiment to lose.

The experiment was largely planned and evaluated by Johannes Geiss at the Physics Institute of the University of Bern , Switzerland . The results include the isotope ratios of the noble gases helium , neon and argon in the solar wind, upper limits for an atmosphere and a magnetic field of the moon (from the narrow directional distribution of the particle tracks in aluminum) as well as indications of the acceleration mechanisms (from the energy distribution). The simple, lightweight and successful experiment was repeated on all lunar missions, with the exception of the last Apollo 17 mission and the failed Apollo 13 mission. The last time it was carried out at Apollo 16, two segments of the sail were made of platinum foil, which allowed more intensive cleaning.

The whole device had a weight of 430 grams, which earned the experiment from Bern from astronaut circles the compliment " most science per pound " . NASA Science Director Thomas H. Zurbuchen described the results of the Solar Wind Composition Experiment during the anniversary celebrations in Bern in June 2019 as an "incredibly important measurement".

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  Solar wind sails (Photo: Apollo 11, detail NASA image AS11-40-5916)

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  Drawing of the solar wind sail in transport configuration

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  Drawing of the solar wind sail from Apollo 11

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  Modified solar wind sail (Photo: Apollo 16, NASA image AS16-117-18849)

literature

• J. Geiss, F. Bühler, H. Cerutti, P. Eberhardt, C. Filleux, J. Meister, P. Signer: The Apollo SWC Experiment: Results, Conclusions, Consequences. In: Space Science Reviews. vol 110, no 3-4, 2004, pp. 307-335
• Preliminary Science Reports of the Apollo Missions, in English:
  • Apollo 11 Preliminary Science Report , pp. 183–186, (PDF file; 24 MB)
  • Apollo 12 Preliminary Science Report , pp. 99–102, (PDF file; 23 MB)
  • Apollo 14 Preliminary Science Report , pp. 221–226, (PDF file; 25 MB)
  • Apollo 15 Preliminary Science Report , pp. 15–1–15–7 (PDF file; 53 MB)
  • Apollo 16 Preliminary Science Report , pp. 14–1–14–10 (PDF file; 59 MB)

Web links

• Hans Balsiger: From the laboratory to space. (PDF; 1.2 MB) In: Space research. 140/2009, UniPress ( University of Bern ), pp. 12–13.
• Bernese caught solar matter. In: Berner Zeitung. July 21, 2009.
• The very first experiment of the Apollo mission - a Swiss idea

Individual evidence

1. ^ In front of the US flag, a Swiss sail was blowing on the moon on Swiss radio and television on June 23, 2019
2. ↑ 9783258073699: Archeology in space: The search for the origin of life - ZVAB - Kathrin Altwegg; Hans Balsiger; Beat Hugi: 3258073694. Retrieved July 3, 2019 . 
3. ↑ Der Bund, Tamedia Espace AG: The man for universal questions . ISSN  0774-6156 ( derbund.ch [accessed on July 3, 2019]).