measured data and the
simulations is 15%. In
addition, a model that
considers orbital altitude,
attitude, and solar cycle
emissions agrees within
25% of the measured
data. It is determined that
the majority of radiation
energy deposited in
human tissues (about
80%) was due to galactic
cosmic radiation. This is
because of spacecraft
material providing
effective reduction from
the protons trapped in
the Earth’s magnetic field.
Finally, this experiment
indicated that the
contribution to both skin
and organ doses from
secondary neutrons is not negligible. Radiation assessments from chromosomal damage in
lymphocyte cells of 19 ISS crew members were conducted as a follow-up study. These results
were compared with space radiation transport models, irradiation of pre-flight blood samples,
and results from the phantom torso experiments. The ISS crew members sampled include the
earliest missions near the solar maximum, and concluding with Increment 15 astronauts, near
the solar minimum. During this timeframe, 67 Solar Particle Events occurred. However, the
extended solar maximum (particular to this solar cycle) decreased the galactic cosmic ray levels.
Average effective doses for a 6-month stay on the ISS were 72 mSv. At least 80% of the organ
radiation exposures come from galactic cosmic rays. Another important result shows that the
models are predictive within about 10%. The authors conclude that many uncertainties about
space radiation remain - both levels and types of radiation and effects inside the spacecraft.
Continued research and analyses are required (Cucinotta 2008).
PUBLICATION(S)
Cucinotta FA, Kim MY, Willingham V, George KA. Physical and biological organ dosimetry
analysis for International Space Station astronauts. Radiation Research. July 2008;170(1):127-
- doi: 10.1667/RR1330.1.
This investigation is complete and all results are published.
ISS002E5952 – The Phantom Torso, seen here in the Destiny laboratory on
the International Space Station (ISS), is designed to measure the effects of
radiation on organs inside the body by using a torso that is similar to those
used to train radiologists on Earth. The torso is equivalent in height and
weight to an average adult male. It contains radiation detectors that will
measure, in real-time, how much radiation the brain, thyroid, stomach, colon,
and heart and lung area receive on a daily basis.