ROOM
44
Space Environment
L. Joseph Parker
MD, Arkansas, USA
B
uilding a space colony that will protect
and sustain a population of hundreds or
even thousands of colonists in an
environment that is hostile to human life
presents huge technological and economic
challenges. One of the greatest challenges for the
first humans living away from Earth will be that of
excessive radiation exposure which can lead to the
early onset of cancers and affect reproduction.
Threats posed by radiation exposure will always
be particularly high for the first colonists tasked
with the job of building habitats and preparing the
infrastructure of a new colony. To understand and
evaluate the threat, scientists have to analyse what
expected radiation exposure levels are, how well
humans can tolerate these levels and what can be
done to mediate the risks.
Understanding radiation
Radiation is energy emitted as electromagnetic
waves or high-speed atomic or subatomic
particles. Radiation waves are generally ‘invisible’,
have no mass and no positive or negative charge.
Some radiation waves, such as light or heat, can
be seen and felt, while others like X-rays can
only be detected by instrumentation. Radioactive
particles are also invisible but they have ‘weight’
and may have a positive or negative charge.
Ionizing radiation converts atoms or molecules
into ions by stripping one or more electrons from
them, breaking molecular bonds and damaging
cells. Examples of ionizing radiation include
X-rays and gamma rays.
Non-ionizing radiation is relatively low-energy
radiation that doesn’t carry enough energy to ionize
atoms or molecules. Radio waves, microwaves and
low energy visible light are generally included in
this category. Ionizing radiation can be categorized
as photonic or particulate.
Photons
Photons have no rest mass and their impact is
determined by their energy levels. Radio waves
have the lowest energy level of all photonic
The long-held dream of humankind to explore and colonise space is closer
than it has ever been. As the budding commercial space mining, tourism and
transportation sectors along with national space agencies extend their reach
further into space, concepts are now being developed with the ultimate goal
of establishing human outposts and colonies on the Moon and Mars. Here, in
the first of two articles, Joseph Parker considers the dangers that different
types of radiation will pose to crews travelling and living beyond Earth. His
second article, to be published in
ROOM
later this year, will suggest how
these extreme radiation risks might be managed and mitigated.
Multi-dome lunar base
being constructed, based
on the 3D printing concept.
Once assembled, the
inflated domes are
covered with a layer of
3D-printed lunar regolith
by robots to help protect
the occupants against
space radiation and
micrometeoroids.
Surviving radiation
for space colonisation
ESA/Foster
