MATROSHKA-1
Research Area: Radiation Impacts on Humans
Expedition(s): 9, 10, 11
Principal Investigator(s): ● Günter Reitz, PhD, German Aerospace Center,
Cologne, Germany
● Victor M. Petrov, Institute of Medical and Biological
Problems of the Russian Academy of Sciences, Moscow,
Russia
RESEARCH OBJECTIVES
Space radiation hazards are a key concern for human spaceflight. Accurate risk assessment
requires knowledge of equivalent doses in critical radiosensitive organs rather than only skin
doses or ambient doses from area monitoring. Matroshka measures space radiation doses from
the diverse components of ionizing space radiation were measured at the surface and at
different locations inside a human phantom positioned outside the International Space Station,
thereby simulating an extravehicular activity of a space explorer.
RESULTS
The relationships between the skin and organ
absorbed doses obtained in such an exposure
showed 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
highlighted the complexities of an adequate
dosimetry of space radiation.
Matroshka data showed the interpolated depth
distribution of dose rates including the skin
measurement. It highlighted the very steep
decline within the first 8 mm by a factor of about
- From this depth-dose distribution, an average
organ dose rate was determined for each critical
organ as the average of the dose rates in those
volume elements that were assigned to it in the
voxel model. The calculated skin dose rate
represents an average of the outermost 3 mm.
With about 1 mGy/day, it is by far the highest,
followed by the dose rate in the eye. With the
exception of the breast and the salivary glands,
the dose rates for the other organs were in the
range from 0.2 to 0.3 mGy/day.
ISS011E13009 – Cosmonaut Sergei K. Krikalev,
Expedition 11 commander representing Russia's State
Space Corporation, works with the European Space
Agency (ESA) Matroshka radiation experiment in the
Zvezda Service Module of the International Space
Station. Matroshka, a human-torso-like device, was
retrieved from the exterior of the station during an
August spacewalk for return to Earth. The experiment
is designed to better understand the exposure of
astronauts, including those making spacewalks, to
radiation.