ROOM
44
Astronautics
L. Joseph Parker MD,
Arkansas, USA
D
reams of colonising space may be
drawing closer to reality with plans now
under development in different parts of
the world for humans to move beyond
Earth and low Earth orbit to explore and live in
space, on the Moon, on Mars or in orbiting colonies.
But leaving home is never easy, and space travellers
moving out of the shelter of Earth’s atmosphere and
magnetic field will have to contend with high levels
of solar and galactic radiation.
Space agencies take measures to limit the time
astronauts spend exposed to radiation, such as
scheduling spacewalks so that they do not occur
during times of intense solar activity and limiting
the amount of radiation they are exposed to
during their careers - but for humans in the future
intending to spend many years in space, prolonged
exposure will be unavoidable.
Scientists and engineers will have to find
creative ways to deal with this danger and unless
it ever becomes possible (or desirable) to alter
human genetic make-up sufficiently to create in-
built protection, the only way to provide radiation
protection in space will be with different kinds of
external shielding technology.
To understand radiation shielding we must
first review different types of radiation – photonic
(electromagnetic wave) and particulate.
Photonic radiation
Photons have no rest mass and their impact,
and the degree of damage they can cause, is
When space crews travel beyond the protection of Earth’s atmosphere
and magnetic field, space radiation becomes a serious hazard. Radiation
permeates empty space and most of the places we would like to colonise,
and surviving the high radiation environment in space will be a vital part
of human effort when it comes to colonising the solar system. Here, in the
second of two articles, Joseph Parker suggests some ways that extreme
radiation risks might be managed and mitigated for crews travelling and
living beyond Earth.
Radiation protection
for space colonists
and travellers
When stem
cells are
severely
damaged
we can no
longer repair
radiation injury
