Scientists have discovered a potentially suicidal problem with going to Mars

first humans mars astronaut glove shutterstock_341700152Shutterstock

  • Cosmic rays are a powerful type of radiation that pose
    a risk to astronauts.
  • Beyond Earth’s protective magnetic shield, they
    increase the risk of cancer and other health effects.
  • The first Mars explorers may face a two-fold higher
    risk than previously thought, according to a recent study in
  • However, researchers may soon develop better radiation

NASA is dead-set on sending astronauts to Mars within the next

15 to 20 years
. China has said it hopes to send people there

between 2020 and 2030
, and even Russia is
floating plans
to put boots on the red planet.

Meanwhile, SpaceX founder Elon Musk is trying to cut the
cost of spaceflight
enough to start establishing a permanent

Martian colony of 1 million people
 as soon as possible.

But if a study of radiation exposure in mice has any bearing on
humans, going to Mars may be much more dangerous than anyone

The root problem is cosmic rays, as detailed in a Nature study and highlighted by a
recent Business Insider

The danger of cosmic rays

Cosmic rays are high-energy atomic and subatomic particles that
get blasted out from exploding stars, black holes, and other
powerful sources in space. The rays can damage DNA, increase
the risk of cancer, lead to vision-impairing cataracts, cause
nervous system damage, and give rise to blood circulation issues,
among other health effects in astronauts.

Researchers know that astronauts receive
much higher radiation exposure
 than those of us who
remain on Earth, since the planet’s atmosphere absorbs a lot
of that harmful energy.

cosmic rays
An illustration of cosmic
rays hitting Earth.


Earth’s magnetic field also diverts and deflects a lot of
space radiation, which helps protect astronauts on the
International Space Station — which orbits just 250 miles above
the planet.

On a trip to Mars, however, it’s open season for cosmic rays.
Health scientist Frank Cucinotta and his colleague
Eliedonna Cacaoat at the University of Nevada Las Vegas
researched this problem by reexamining the results of four
previous studies of tumors in mice.

In addition of looking for the effects of a cosmic ray’s
direct hit to cells, which could coax them to develop into
cancer, the researchers also looked at how secondary or
“non-targeted effects” might play a role.

What they found is a risk of cancer in deep space (at least for
mice) that’s about two times higher than previous estimates.

Why deep-space travel may be more dangerous than expected

The researchers think this elevated cancer risk comes down to how
damaged DNA spreads throughout the body.

When a cell is struck by a cosmic ray, it doesn’t simply keep the
change to itself. It can give off chemical signals to other
cells, which might trigger nearby healthy cells to also mutate
into cancer.

Previous models hadn’t really accounted for this domino effect.
Even more worrisome, the type of radiation responsible for
causing the effect was “only modestly decreased by radiation
shielding,” Cucinotta and Cacao wrote in their study.

Human exploration of Mars need not stop before it starts, though.

astrorad mars radiation shield suit reuters RTS119FE
of the Astrorad radiation shield suit for deep-space


Space agencies and private companies are actively working to
mitigate space radiation. An Israeli startup is developing a

body vest designed to more fully absorb radiation
, for
example, and one NASA scientist recently pitched the idea of
deploying a satellite that’d serve as an artificial magnetic
shield to
divert harmful radiation around Mars

And as the researchers noted in their study, “significant
differences” exist between mouse-model cancer rates and those
actually seen in people. “These differences could limit the
applicability of the predictions described in this paper,” they

But the scientists add that this knowledge gap is precisely why
future deep-space explorers and their respective agencies should
exercise caution.

“[S]tudies … are urgently needed prior to long-term space
missions outside the protection of the Earth’s geomagnetic
sphere,” they said.

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