ROOM
47
Astronautics
The crew could also, of course, use a storm
shelter, like that on the International Space Station,
to wait out any major radiation storm. The active
magnetic shielding method could be effective
for individual buildings or even large settlements
that generate lots of power but would not be very
practical for space-suited colonists in the open on
the Moon, Mars or elsewhere in space.
The power requirements and mass required
would limit mounting such a system on a space
suit until our batteries are much smaller and more
powerful. Unprotected time in space will always
have to be carefully monitored and limited to
prevent radiation sickness or early cancer.
Wearable radiation protection
Space suits create a protective environment for
the wearers providing essential air pressure and
oxygen in the vacuum of space and give protection
from extreme temperatures and from small pieces
of space dust. But they provide only limited
shielding against radiation
Most of the damage from acute radiation exposure
is produced in the bone marrow. This is the source of
stem cells that we need to repair damage elsewhere
in the body and is one of the most vulnerable organ
systems to radiation exposure, because the limited
life-span of blood cells requires continuous cell
divisions of hematopoietic stem cells in the bone
marrow. If the bone marrow is severely damaged we
can no longer repair radiation damage, leading to
medical conditions that can be fatal.
One cutting-edge technology that may help
future astronauts has been devised by an Israeli-
American company called StemRad. The AstroRad
Radiation Shield is a multi-layered vest that will
be tailor-made of non-metallic shielding materials
which will be positioned to protect the bone
marrow and other organs from radiation.
Only about five percent of the bone marrow
needs to survive a high radiation event in order
to replace the rest and provide healing stem cells,
and shielding the entire body would be too bulky
and inflexible to allow freedom of movement.
Creating a vest that shields the body’s core while
allowing normal movement is a great balance of
protection and functionality.
The vest is due to be tested on the Orion mission
scheduled to orbit the Moon in late 2018. It will
be attached to a ‘phantom’ torso dummy, a device
used to monitor radiation absorption, and a second
phantomwill fly unprotected so that the comparative
results can be analysed after they return to Earth.
Almost certainly a combination of these
technologies will be needed to successfully protect
future astronauts and colonists as they venture
into deep space.
About the author
L. Joseph Parker
has a doctorate of medicine from the Mayo Clinic with
honours in Neuroscience, and a Master’s of Science in Space Studies from
the American Public University. He was a Captain in the US Air Force, serving
first as a Minuteman II ICBMDeputy Commander at Malmstrom AFB in
Montana, and also with the US Strategic Air Command and later with US
Space Command. He went to medical school becoming an Air Force doctor
and now practices emergency medicine and has a private clinic.
The AstroRad Radiation
Shield vest developed by
StemRad will be tailor-
made for individual
astronauts. It was on show
at the 33rd Space
Symposium in Colorado
Springs earlier this year.
Unprotected
time in space
will always
have to be
carefully
monitored
and limited
to prevent
radiation
sickness or
early cancer
A cutaway illustration of
NASA’s Orion capsule.
