EXTRA VEHICULAR ACTIVITY RADIATION MONITORING (EVARM)
Research Area: Radiation Impacts on Humans
Expedition(s): 4-6
Principal Investigator(s): ● Ian Thomson, PhD, Thomson and Nielsen Electronics, Ottawa,
Ontario, Canada
RESEARCH OBJECTIVES
The aim of the Extra Vehicular Activity Radiation Monitoring (EVARM) investigation is to
determine the levels of radiation dose received to the skin, eyes, and blood-forming organs
(BFOs) of crew members during extravehicular activity (EVA). The data determined which parts
of the human body are exposed to the highest radiation levels so that routine dosage
monitoring in future missions can be done on the appropriate parts of the human body.
EARTH BENEFITS
The shielding designed for this
experiment can also be used to
protect people who receive X-rays
and CAT scans and people working
in areas exposed to high levels of
radiation, such as nuclear power
plants.SPACE BENEFITS
The information gathered will help
determine which parts of the body
are exposed to the highest levels
of radiation, in order to improve
spacesuit shielding.RESULTS
In the EVARM experiment,
radiation was measured by means
of 3 dosimeters in the form of small badges. These dosimeters are metal-oxide semiconductor
field effect transistors (MOSFETs) carried in pockets inside the astronaut's spacesuit during
EVAs. Data recorded by these badges were then transferred to a laptop computer and sent to
researchers. The EVARM experiment measured the radiation delivered to the most sensitive
organs: the skin, eyes, bone marrow, and lymphatic organs. Spacesuit shielding influences the
quantity and type of radiation absorbed by astronauts. Overexposure may burn the skin, cause
cataracts in the lens of the eye and the immediate depletion of blood cells, as well as increase
the risk of cancer. A comparison of the internationally recognized limits of radiation exposure
for workers and the maximum allowed doses for astronauts shows 0.50, 0.15, and 0.02 sieverts
per year for skin, eye, and blood-forming organs in nuclear industry workers, while astronauts
receive 3.00, 2.00 and 0.50 sieverts per year. Radiation exposure for astronauts is therefore 6
ISS005E22017 – International Space Station Expedition 5
Commander Valery Korzun during an extravehicular activity (EVA).
The Extra Vehicular Activity Radiation Monitoring experiment
measures the amount of radiation that astronauts absorb during
EVA.