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NARRATOR: Microscopic germs hidden from the naked eye.
Throughout history, these mysterious invaders
have wreaked havoc on mankind with devastating outbreaks
of disease.
The best minds of science have searched for the origins
of these epidemics.
Now, a respected astrobiologist suggests
that some of the worst pandemics may have come from outer space.
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I think every new epidemic disease
had come from space originally at one point in time.
NARRATOR: If this controversial theory is correct,
it could help solve the mystery of the origins
of some of the deadliest epidemics in history.
For thousands of years, people had no idea
what caused diseases and how they were spread.
Then in the mid 19th century, scientists
discovered that some diseases were caused
by microbes called bacteria.
50 years later, scientists discovered
even smaller disease-causing agents called viruses.
It wasn't until the 1920s, '30s or '40s that we had
devices like electron microscopes that would allow us
to see these very tiny viruses, visualize them, and figure
out a little bit about them.
NARRATOR: Although the origins of some diseases
have remained a mystery, science has
been able to answer many of the questions
about how germs are transmitted.
Throughout history, diseases were often spread by travelers.
HOWARD MARKEL: As long as people have been traveling, so, too,
have the germs that reside in those beings.
NARRATOR: Science has made enormous progress
in understanding the transmission of germs,
and yet the best minds have been unable to answer
one basic question.
Where do diseases originate?
In answer to this question, Chandra Wickramasinghe,
the director of the Cardiff Center for Astrobiology,
has advanced a controversial new theory.
He believes that some of mankind's deadliest pandemics
have emanated not from Earth but from outer space.
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Chandra's work began over three decades ago in conjunction
with the late astronomer Sir Fred Hoyle.
They investigated the possibility that life
is not confined to Earth.
Life is indeed a truly cosmic phenomenon,
that it's not an Earth-bound thing,
that we are part of a connected chain of being
that goes through the comets to the remotest
parts of our universe.
NARRATOR: This theory is known as panspermia, the hypothesis
that life on Earth originated elsewhere in the universe.
There has to be an enormous range
in the types of micro-organisms that are around in the cosmos.
We have interacted, and we have, in fact, evolved from a subset
of these microorganisms.
We have to conclude that our genetic ancestors
still lurk amongst the stars.
NARRATOR: Chandra believes that the seeds of life
were transported to Earth by comets 4 billion years ago.
Chandra believes that some viruses
could survive even the harshest conditions in space.
The notion that disease-causing organisms come from space
may explain the odd patterns of certain historical epidemics.
In some Eskimo villages, up to 90% of the population died.
Doctors of infectious disease say this is a perfect example
of viral naivete in which a population without immunity
is more vulnerable to a disease.
Still, this does not explain how the epidemic jumped from one
isolated village to another.
They had to use the most tedious ways to go from one end
of Alaska to another, and the person-to-person
contact is just impossible in those situations.
NARRATOR: What about an alien infection
brought here by a returning spacecraft?
The stuff of science fiction, perhaps, but experts
treat the possibility very seriously.
The notion that it is dangerous to move material
from one planet to another has been
a concern of many scientists involved
with space exploration.
Article nine of the 1967 Outer Space Treaty signed
by more than 90 nations dictates that all countries
will avoid harmful contamination of the Earth.
MARGARET RACE: When we sent astronauts to the moon
during the Apollo program, the provisions
of the Outer Space Treaty were put to their first test.
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At the time the astronauts came back,
they were quarantined along with the rocks and samples
that they brought back.
NARRATOR: NASA continues to be concerned that a returning
space probe could bring back an alien organism that
would infect our biosphere.
What's the probability that that sample might have
something in it that could be infectious or biohazardous
to humans?
It's very low but not zero.
NARRATOR: In the search for extraterrestrial life,
NASA scientists have long considered the planet
Mars the best nearby candidate.
MARGARET RACE: If you move organisms from one place
to another place beyond where they would normally disperse,
you can have surprising outcomes when the new populations
interact with each other.
NARRATOR: NASA's policy is to treat
any sample as hazardous until proven otherwise.
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In the quest to return a Mars sample to Earth,
NASA has anticipated just about everything that might go wrong.
WOMAN: Spaceflight is a risky business.
Probably the biggest threat would
be that it crashed and was exposed to the environment.
MAN (ON RADIO): It looks like we have a no chute, sir.
Vector 2-0-0--
MAN (ON RADIO): Mission manager--
MAN (ON RADIO): On the nose--
NARRATOR: An accident is a very real
possibility as evidenced from the crash
of the Genesis capsule in 2004.
NASA engineers will safeguard against this possibility
by building a craft that is designed
to handle a hard landing.
[helicopter whirs]
Even if the capsule crashes, the container that holds the Mars
sample will remain intact.
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MARGARET RACE: The capsule would be picked up at that point
and transported to a quarantine module
and then to a receiving lab.
NARRATOR: This facility would meet biosafety level 4
containment standards.
MARGARET RACE: Biosafety level 4 is the maximum containment used
by Center of Disease Control and others
when handling the most virulent organisms on Earth,
not because we think that a virulent
organism would be in the sample but because we don't know.
And in that uncertainty, we want to take the conservative route,
which means to treat it the strictest way
you can until you know more.