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starship-design: Mars sample return plan carries microbial risk, group warns

Mars sample return plan carries microbial risk, group warns

November 7, 2000
Web posted at: 12:52 PM EST (1752 GMT)

By Richard Stenger
CNN.com Writer
(CNN) -- Should NASA bring back Mars soil or rock to Earth? While the space
agency hopes to accomplish that feat within the decade, the International
Committee Against Mars Sample Return (ICAMSR) warns it could infect Earth
with an interplanetary plague.

NASA unveiled in October a wish list of unmanned missions to Mars in the
early 21st century, culminating in several roundtrip flights that would
bring home multi-kilogram chunks of the red planet. Terrestrial scientists
would poke and prod the samples for evidence of past or present microbial

ICAMSR, a group of professional scientists and amateur space enthusiasts,
thinks there is a chance that earthlings might find more than they bargained
for. A Mars microbe could wreak havoc on terrestrial species, which would
have no natural defenses against the alien invaders.
"If we make one mistake it could mean the extinction -- maybe for our
species, or maybe another, for instance bumble bees or photoplankton, which
are a huge part of our ecology," said ICAMSR founder Barry DiGregorio.

Many planetary scientists dismiss the risks as unwarranted or highly
exaggerated, saying the surface of Mars is most likely lifeless, anyway.

Moreover, the samples, once recovered from protective canisters that land
via parachute in the American desert, would be contained in laboratories and
handled as if they contained deadly and highly infectious organisms.

"NASA is taking the necessary precautions," said John Rummel, NASA's
planetary protection officer. The returned samples will be "kept in a
controlled environment with as many precautions as possible."

Rummel points out that the Earth naturally receives geological samples from
Mars all the time. Dozens or hundreds of kilograms of martian meteorites hit
the planet each year. If martian microbes exist they would have invaded
Earth long ago, inoculating terrestrial life forms in the process, according
to Rummel and other planetary scientists.

DiGregorio remains undaunted.

"This is a great fallacy and it's unscientific as well," he said.

In fact, DiGregorio, the author of "Mars: The Living Planet," suggests
epidemics that originate in space might have already taken place. Mass
extinctions over the ages have been tied to giant meteorite or comet
strikes. But such cataclysms could perhaps be more fully explained, he said,
if science considers the possibility that extra-terrestrial viruses played a
role, for example when the age of the dinosaurs ended 65 million years ago.

"The dinosaurs did not die out that day. It took 2.5 million years for them
to go extinct. If the dinosaurs survived the initial impact, why didn't they
go on?" DiGregorio said.

Many are skeptical of DiGregorio, but fellow ICAMSR members include a
handful of prominent scientists, like Chandra Wickramasinghe, one of the
first to put forward the increasingly accepted theory that complex organic
molecules riddle deep space. Another is Gilbert Levin, who designed
experiments to detect life for Russian and U.S. Mars missions.

Though most of his peers concluded otherwise, Levin still holds that the
robot tests he coordinated on the 1976 Viking lander indicated the presence
of living organisms on Mars. DiGregorio cites Levin's work as evidence that
robots should poke around more for life on Mars before they return to Earth
with samples.

Yet NASA plans to forego life detection experiments on missions for the next
15 years or so. Only a European lander called Beagle 2 will sniff the planet
for signs of life. It is scheduled to arrive on the red planet in about
three years.

But NASA's Rummel said such tests would be insufficient. If microbes do
exist on Mars, experiments based on human understanding of life might be too
limited to detect them.
"Tests on Mars for life are not necessary because if it tests negative, it
still doesn't mean there is no life. And if it's positive, you cannot
possibly take more precautions than NASA plans," he said.

Such assurances do little to placate DiGregorio.

"We simply do not have the technology or the means yet to pull off a safe
sample return mission," he said. "Can we afford to make a mistake with this,
something that might carry a deadly virus?"