title: Astronaut's organ doses inferred from measurements in a human phantom outside the international space station.
abstract: Space radiation hazards are recognized as a key concern for human space flight. For long-term interplanetary missions, they constitute a potentially limiting factor since current protection limits for low-Earth orbit missions may be approached or even exceeded. In such a situation, an accurate risk assessment requires knowledge of equivalent doses in critical radiosensitive organs rather than only skin doses or ambient doses from area monitoring. To achieve this, the MATROSHKA experiment uses a human phantom torso equipped with dedicated detector systems. We measured for the first time the doses from the diverse components of ionizing space radiation at the surface and at different locations inside the phantom positioned outside the International Space Station, thereby simulating an extravehicular activity of an astronaut. The relationships between the skin and organ absorbed doses obtained in such an exposure show a steep gradient between the doses in the uppermost layer of the skin and the deep organs with a ratio close to 20. This decrease due to the body self-shielding and a concomitant increase of the radiation quality factor by 1.7 highlight the complexities of an adequate dosimetry of space radiation. The depth-dose distributions established by MATROSHKA serve as benchmarks for space radiation models and radiation transport calculations that are needed for mission planning.
authors.affiliation: German Aerospace Center, Cologne, Germany. guenther.reitz@dlr.de
authors.forename: Guenther
authors.initials: G
authors.lastname: Reitz
authors.forename: Thomas
authors.initials: T
authors.lastname: Berger
authors.forename: Pawel
authors.initials: P
authors.lastname: Bilski
authors.forename: Rainer
authors.initials: R
authors.lastname: Facius
authors.forename: Michael
authors.initials: M
authors.lastname: Hajek
authors.forename: Vladislav
authors.initials: V
authors.lastname: Petrov
authors.forename: Monika
authors.initials: M
authors.lastname: Puchalska
authors.forename: Dazhuang
authors.initials: D
authors.lastname: Zhou
authors.forename: Johannes
authors.initials: J
authors.lastname: Bossler
authors.forename: Yury
authors.initials: Y
authors.lastname: Akatov
authors.forename: Vyacheslav
authors.initials: V
authors.lastname: Shurshakov
authors.forename: Pawel
authors.initials: P
authors.lastname: Olko
authors.forename: Marta
authors.initials: M
authors.lastname: Ptaszkiewicz
authors.forename: Robert
authors.initials: R
authors.lastname: Bergmann
authors.forename: Manfred
authors.initials: M
authors.lastname: Fugger
authors.forename: Norbert
authors.initials: N
authors.lastname: Vana
authors.forename: Rudolf
authors.initials: R
authors.lastname: Beaujean
authors.forename: Soenke
authors.initials: S
authors.lastname: Burmeister
authors.forename: David
authors.initials: D
authors.lastname: Bartlett
authors.forename: Luke
authors.initials: L
authors.lastname: Hager
authors.forename: József
authors.initials: J
authors.lastname: Pálfalvi
authors.forename: Julianna
authors.initials: J
authors.lastname: Szabó
authors.forename: Denis
authors.initials: D
authors.lastname: O'Sullivan
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kitamura
authors.forename: Yukio
authors.initials: Y
authors.lastname: Uchihori
authors.forename: Nakahiro
authors.initials: N
authors.lastname: Yasuda
authors.forename: Aiko
authors.initials: A
authors.lastname: Nagamatsu
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tawara
authors.forename: Eric
authors.initials: E
authors.lastname: Benton
authors.forename: Ramona
authors.initials: R
authors.lastname: Gaza
authors.forename: Stephen
authors.initials: S
authors.lastname: McKeever
authors.forename: Gabriel
authors.initials: G
authors.lastname: Sawakuchi
authors.forename: Eduardo
authors.initials: E
authors.lastname: Yukihara
authors.forename: Francis
authors.initials: F
authors.lastname: Cucinotta
authors.forename: Edward
authors.initials: E
authors.lastname: Semones
authors.forename: Neal
authors.initials: N
authors.lastname: Zapp
authors.forename: Jack
authors.initials: J
authors.lastname: Miller
authors.forename: Jan
authors.initials: J
authors.lastname: Dettmann
mesh_terms: D003359:Cosmic Radiation; D006801:Humans; D008953:Models, Anatomic; D013026:Space Flight