Dosimetry in Air- and Spaceflight

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Image 1: The Matroshka Puppet („clothed“)

Dosimetry in Aerospace

Dostel

The affects of cosmic radiation on biological cells is a fundamental risk factor for human space travel. The dosage levels are explicitly higher than on radiation exposed work areas on earth. Manned space missions must therefore be closely monitored for radiation protection. Similar areas with high amounts of radiation exist in the upper atmosphere down to the flight heights of modern airplane traffic. Radiation protection laws also require the radiation levels to be monitored for the crew of airplanes. This monitoring is carried out by numerous institutes, including the IEAP (Institute of Experimental and Applied Physics) at the University of Kiel with the use of the DOSimetry-TELeskope, DOSTEL.

The MATROSHKA Mission

  • • European-Russian mission on the International Space Station, ISS, with a puppet imitating a human torso to measure the radiation dosage to inner organs
  • • Launch on January 29, 2004, with a Russian Proton rocket to the ISS. Both ISS astronauts successfully mount the puppet on the outside of the space station on February 26, 2004.
  • • Mission length of about one year with an extension possible

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Image 2: Matroshka Puppet(„naked“)

Kiel’s Contribution

The work group for extraterrestrial dosimetry began measuring manned space travel in 1972 with participation on the moon missions of Apollo 16 and 17. Since then, the radiation fields in orbit have been measured on more than 30 missions in and outside of the space shuttle. Aside from dosimetry, the following scientific fields have been researched

  • Composition of the galactic and solar particle radiation
  • The earth’s radiation belt
  • The effects of the earth’s magnetic field
  • Shielding of space shuttles
  • Changes of the primary radiation in the atmosphere

Passive and active detector systems are used. The passive systems are composed of a package of 0.25 mm thick plastic film which the ionized particles leave latent traces on when they pass through. Similar to a photographic emulsion, the images are made visible after the mission has returned and the film is developed under a light microscope in our laboratory for further analysis. The use of these passive detectors is therefore limited to mission that allow a return of our experiments. The active systems use 0.3 mm thick silicon-detectors that give off an electric pulse when a particle passes through. The pulses are then processed and saved on a connected switch. This data is then sent to earth with a radio signal and therefore can be analyzed directly or with a slight delay. A return of the instruments to the earth is not necessary. However, because our active instruments have so far only been on manned missions, they have always come back with the crew and have partially been used on later missions. Kiel’s experiments in dosimetry in space have been used until now for, among others, numerous flights of NASA shuttles (since STS9 in 1983) as well as on the two long-term missions of the MIR station and the international space station ISS. In cooperation with Lufthansa, Condor and other airlines, we have taken measurements in commercial airplanes with Kiel’s detector system which has been seasoned in space travel. Our measurements have contributed to an understanding of the connection between radiation exposure and the plane’s flight height.