Astronaut's organ doses inferred from measurements in a human phantom outside the international space station.
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.
Reitz
Guenther
G
German Aerospace Center, Cologne, Germany. guenther.reitz@dlr.de
Berger
Thomas
T
Bilski
Pawel
P
Facius
Rainer
R
Hajek
Michael
M
Petrov
Vladislav
V
Puchalska
Monika
M
Zhou
Dazhuang
D
Bossler
Johannes
J
Akatov
Yury
Y
Shurshakov
Vyacheslav
V
Olko
Pawel
P
Ptaszkiewicz
Marta
M
Bergmann
Robert
R
Fugger
Manfred
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Vana
Norbert
N
Beaujean
Rudolf
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Burmeister
Soenke
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Bartlett
David
D
Hager
Luke
L
Pálfalvi
József
J
Szabó
Julianna
J
O'Sullivan
Denis
D
Kitamura
Hisashi
H
Uchihori
Yukio
Y
Yasuda
Nakahiro
N
Nagamatsu
Aiko
A
Tawara
Hiroko
H
Benton
Eric
E
Gaza
Ramona
R
McKeever
Stephen
S
Sawakuchi
Gabriel
G
Yukihara
Eduardo
E
Cucinotta
Francis
F
Semones
Edward
E
Zapp
Neal
N
Miller
Jack
J
Dettmann
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D003359:Cosmic Radiation; D006801:Humans; D008953:Models, Anatomic; D013026:Space Flight