PUTATIVE MARTIAN LIFE NO THREAT TO EARTH?
by Barry E. DiGregorio
Dr. Robert Zubrin's surprising and arrogant comments regarding planetary
protection policy and back contamination issues in the July/August Planetary
Report left me wondering if he had blown a gasket with his quest to put humans
on Mars. He states in the article that anyone who believes that human Mars
explorers could be infected by putative Martian organisms is not only
"Illusory but hallucinatory". Is that a fact Dr. Zubrin? You better
mention that to NASA's Planetary Protection Officer Dr. John Rummel because
Rummel still seems to think there is a reason for his job.
Zubrin then cites that the return of Martian soil samples could not be harmful
in anyway! He says "the kindest thing that can be said about this argument
is that is just plain nuts". Obviously Zubrin is of the opinion that
NASA's planetary protection program is a waste of time and money. While I can
appreciate Dr. Zubrin's zeal and gung-ho-humans-to-Mars philosophy, he is out
of his field with his comments on forward and back contamination. I find it incredibly
amusing that Zubrin does not mention the recent Space Studies Board report
titled "Preventing the Forward Contamination of Europa".
Spawned over the issue of whether or not to crash the Galileo spacecraft into
Europa, great concern was expressed by a number of scientists (biologists) in
this report who advocated avoiding the contamination of Europa with Earth
microbes contained within the spacecraft. The Surveyor III lunar probe
brought back to Earth by the Apollo 12 crew demonstrated the survival of
Earth organisms for 2 1/2 years inside the probe. Given the unbelievably
harsh conditions at Europa compared to Mars, one has to wonder why
Robert Zubrin and others who share his "no-planetary-protection-policy-needed"
philosophy do not have the same concerns for protecting Earth against
Martian microbes as the Space Studies Board has for the Jovian moon Europa?
In 1981, NASA published a detailed study entitled "ORBITING QUARANTINE
FACILITY: The Antaeus Report" (NASA SP-454). The purpose of the book is
"A design is presented for an earth-orbiting facility for the analysis of
planetary return samples under conditions of maximum protection against
contamination but minimal damage to the sample. The design is keyed to a
Mars sample return mission profile, returning 1 kg of documented subsamples, to
be analyzed in low earth orbit by a small crew aided by automated procedures,
tissue culture and microassay. The facility itself would consist
of Spacelab shells, formed into five modules of different sizes with purposes
of power supply, habitation, supplies and waste storage, the linking of the
facility, and both quarantine and investigation of the samples. Three barriers
are envisioned to protect the biosphere from any putative extraterrestrial
organisms: sealed biological containment cabinets within the Laboratory Module,
the Laboratory Module itself, and the conditions of space surrounding the
Clearly, this NASA report took a hard look at the issue of back contamination
from Mars very seriously, to the point of building a special facility for that
purpose in Earth orbit. Of course dwindling NASA support and funding virtually
eliminated any possibility of constructing the Orbiting Quarantine Facility
described in the book. However, since the time the NASA Antaeus Report was
written, increasing evidence for life on Mars has been accumulating such as the
recent discovery by Dr. Steven Benner of the University of Florida's Department
of Chemistry. Benner published a paper in the PNAS journal citing the inability
of the Viking GCMS to find organics on Mars in 1976. Benner says the GCMS could
have missed organic matter he believes must be in the Martian soil from
meteorites. He says any organic molecules derived from life processes could
also have been missed. It was the Viking GCMS that was used by NASA in 1976 to
render the verdict that no evidence for life had been found on Mars by the
Viking biology instruments, even though they produced intriguing results.
Viking Project scientist Gerald Soffen is often quoted as saying regarding the
GCMS findings: "That's the ball game, no organics, no life". NASA
then announced to the press that Viking found no evidence for life - a
completely unjustified conclusion. Why? Because former Viking biology
experimenter Dr. Gilbert Levin and his co-experimenter Dr. Patricia Ann Straat
had said their data from Mars was consistent with a biological
response. Dr. Benner's paper in PNAS is now supporting evidence of a flawed
More recently, Dr. Michael Malin and colleagues published a paper in Science in
June of this year describing new evidence that Mars may have liquid water very near
its surface today. This dramatically improves the likelihood of extant life on
Another key issue raised in the Antaeus Report is not even mentioned by Zubrin.
Organisms taken from their natural environment and placed in a completely
foreign environment not only out-competed indigenous organisms but also
flourish. What if this scenario also happens with any organisms
brought back from Mars? Surely, the possibility has to be considered. That is
why we have a planetary protection program in the first place.
Dr. Zubrin accepts the notion of planetary exchange of debris, but uses this to
conclude that Earth has already been inoculated against germs from Mars. Is
this really a rational theory? Where is the supporting evidence to make a case
to abandon planetary protection? Who is to say that such interplanetary
infections have not been the cause of unexplained extinction’s of species on
Earth in the past? Was disease also a culprit in the extinction of the
dinosaurs. Many scientists now think so. The K-2 impact event 65 million years
ago did not kill off the dinosaurs, they lived on another 2 million years.
Also, Dr. Ross McPhee of the American Museum of Natural History has now
postulated that a species crossing hyperdisease killed off the Pleistocene
mammal’s 13,000 years ago. Are we so sure that interplanetary infection was
not a cause? Dr.'s Chandra Wickramasinghe and Fred Hoyle from Cardiff
University in England have correlated cometary tail debris with outbreaks of
influenza on Earth. Shouldn’t we look into this sort of information more
closely before returning samples from comets or planets considered to be
The horrific truth about microbes is that all they need is to find Earth-life
to be a good source of food, and to have the capacity to harvest it. H. G.
Wells' "War of the Worlds" had a favorable outcome, but Wells'
invaders were not microorganisms, although his story ends with Earth microbes
killing off the Aliens.
Even if Zubrin's assumptions are considered reasonable by some, his
argument does not hold against different reasonable assumptions. When the
entire biosphere hangs in the balance, it is adventuristic in the extreme to
bring Martian life here, or send astronauts to Mars before we know the
capabilities of any organisms that might exist there. Sure, there is a chance
it would do no harm; but that is not the point. Unless you can rule
out the chance that it might do harm, you should not embark on such a course
before making absolutely certain.
Any rational benefit-risk study would find that any conceivable benefit pales
before the risk-no matter how small-to our biosphere. Science must move in
increments when dealing with hazardous unknowns. We should first send many
more robotic probes to seek and characterize life, something we have barely
begun. Only one mission ever searched for life on Mars -- that was Viking
over 24 years ago and it returned positive signals! The Viking biology data
should be a warning. The Beagle 2 exobiology lander may shed more
light in 2003.
So while we are waiting for the issue of life on Mars to be settled, why not
use our time wisely by developing new human space flight technologies and then
practice them on Earth or the Moon for an eventual human mission to Mars? In
this way, we do not have to risk any lives or our biosphere. When dealing with
issues involving planetary protection we must have patience. Remember that old
phrase "An once of prevention equals a pound of cure?" In exposing
Earth to unknown risk, this is an enormous understatement.
Barry E. DiGregorio is the founder of the International
Committee Against Mars Sample Return (ICAMSR)
and author of Mars: The Living Planet.