reported on a project underway by the European Space Agency to study
the effects of radiation on astronauts who may be in space for prolonged
periods of time. The ion beam generator at GSI promises the ability to study
such effects on delicate tissues.
A research group at Georgetown University's Lombardi Comprehensive Cancer
Center agrees with the dangers that
interplanetary and future interstellar travel may pose to space-faring men
and women. Experiments performed on mice with high-LET, or linear energy
transfer radiation, similar to the kind of radiation astronauts may experience,
has shown increased risk factors for cancers and premature aging.
The tests showed that exposure to high-LET radiation causes concentrated
amounts of free radicals in mice gastrointestinal tracts, as well as an
elevated level of stress response gene expression. Free radicals cause an
oxidative environment, which can often lead to the formation of cancerous cells.
Also observed in the study was a premature aging affect on the animals. The
exposed mice's fur turned grey much earlier in their life than normal. The
research group intends to conduct MRI brain scans to determine if there were
other aging affects caused by the radiation exposure.
High-LET radiation can be composed of several things including gamma radiation,
high-energy protons, and charged iron particles. Solar flares contain high
amounts of high-LET radiation. Space travelers will be subject to this and
other types of radiation constantly and from all directions.
The dangerous difference between human-employed radiation, such as that of
medical imaging and radiotherapies, which is considered low-LET, and
space-dwelling radiation is its effect on tissues. While low-LET radiation has
a low impact diffuse effect, high-LET emissions cause damage to localized
One thing both studies agree on is the need for more data on the dangers of
space travel to humans. The more scientists understand about these dangers, the
safer space travel will become. Engineers will design safer craft while medical
scientists develop means to combat radiation exposure. Perhaps with something
as simple as an anti-radiation
pill supplement, Mars-bound men and women will weather the long voyage with
less duress and return safely and healthily to Earth.