Will we be the ones contaminating the Martians?
We all know. The search for life in the Solar System,
and on Mars in particular, represents a bit of the Holy Grail of human exploration in space.
Almost every mission that starts with the intent to descend on other worlds is in fact accompanied
by an emphasis that is usually reserved only for the noblest enterprises. And this is the sign of
how great and widespread is in our species the desire not to feel alone in this great universe.
And someone in the upper echelons of NASA and other space agencies must have understood this
for a while. So much so that the word life has become the password that more easily than others
opens the doors of government grants and captures the attention of an otherwise distracted public.
It's nice, in fact, to know that a large state organization like NASA
has in its charter a commitment to search for "life" in the universe.
It makes us feel reassured in our beliefs. Doesn't it?
However, there is one thing that not everyone knows, and that is that the
last real interplanetary mission conceived and launched to search (for real!) for life
on Mars was that of the Viking probes. We are talking about 1976, when the two NASA landers
made the only attempt ever to find life on Mars, conducting on site specific biological experiments
in search of evidence of microbial life. Experiments that, by the way,
even today many biologists believe, contrary to what was stated by NASA, have been successful.
Since then, inexplicably, despite the fanfare that accompanied the departure of every single
Martian mission, None of the subsequent landers or rovers sent by NASA to Mars brought with
them an instrument capable of following up on those controversial but exciting results...
In short, for nearly half a century now, NASA has pretty much stopped looking for life on Mars.
Over the years it has always continued to claim that the purpose of Martian exploration
was to find or disprove life, but in fact the probes sent were absolutely unable to fulfill
the mission for which they were presented to the world. All subsequent missions to Viking
were in fact designed to study the Martian environment from the geological point of
view and not to confirm or not that among the sands of Mars there could be microbial life.
But not only that. There's also something else that most people who are passionate
about space endeavors probably don't know... Although completely unsuitable for the search
for life, the Martian rovers have always been absolutely forbidden to get closer than 2.5 km
from certain places where life could have had the opportunity to find the best conditions to settle!
In practice, while the media was proposing the mantra of "let's go looking for life!",
the agencies sent on Mars rovers suitable only for geological exploration,
and moreover in places absolutely arid and far from the outcropping points of liquid water. The
reason? The protocol of "planetary protection"! The Outer Space Treaty of the United Nations,
in fact, since 1967 prohibits the "dangerous contamination" of other worlds with
terrestrial biological forms, and an international organization called COSPAR (Committee on Space
Research) establishes protocols for the protection of the planets to which must follow the United
States, Europe, Russia and other signatory nations that are going to travel in space.
To protect Mars, since 2002 COSPAR has defined some restricted "special regions" on the planet,
where the temperature and humidity could be sufficient to support the life of Martian
organisms or terrestrial invaders. Special regions that have obviously
been identified along the equator and in the mid-latitudes of the planet,
in eroded and steep gullies, rocky hillsides and craters where brackish water flows from aquifers
during Martian summers. Or in caves, under polar ice caps, and in geothermal hotspots
of seismic or volcanic activity. No human artifacts can approach
any of these sites, for fear that the eventual Martian life form may be eliminated
or hybridized by terrestrial microbes. And it is precisely to avoid the unintentional export of
terrestrial organic material that spacecrafts are carefully sterilized before each launch.
It has been ascertained, however, that on our planet there are several microorganisms that can
resist even the most ferocious sterilization, as well as the prohibitive conditions of
interplanetary space during the Earth-Mars crossing... so much so that it seems that it is
not possible to exclude that once arrived on Mars some bacteria may awaken and find asylum
in the most humid and hot areas of the planet. The study, developed by astrobiologist Andrew
Schuerger and collaborators at the University of Florida, has in fact verified the survival
and reproduction capabilities of some terrestrial microorganisms in a Martian environment simulated
in the laboratory. The bacterial cultures were kept in chambers with pressures of 7 millibars
(on Earth at sea level pressures are around 1000 millibars), carbon dioxide-based atmosphere
without oxygen, temperature at 0 degrees Celsius, no humidity; coming to prove that
a common terrestrial bacterium such as Serratia liquefaciens, present on the human body, animals
and plants, could take root and multiply even in the hostile environmental conditions of Mars,
demonstrating adaptive capacity even superior to those of other bacteria that live on Earth in
extreme conditions, the so-called extremophiles. But if sterilized robots cannot be trusted to
venture into special regions, what about humans? NASA is planning to send humans to Mars by 2030;
and understandably, the fact that those missions may involve contamination risks is not something
the agency wants to highlight just as it is busy studying possible solutions to the problem.
Not least because it would be difficult to explain to citizens why a human mission
costing tens of billions of dollars should be barred from the most promising regions
from a biological research perspective... And if a human crew landed in an area deemed
unsuitable for life, but discovered habitable conditions or living forms,
would they have to move immediately, pick up the rocket, and return to orbit?
These and other unanswered questions show how the discovery of a Martian biosphere could be,
for different reasons, the realization of NASA's greatest dream or its worst nightmare.
Until now, the "planetary protection" of Mars has been about robotic exploration. The risk of
contamination is also an issue for machines, but unlike humans, they can tolerate being irradiated
and flooded with harsh chemicals before launch to destroy clandestine bacteria.
Under these assumptions, however, planetary protection would come to exclude the human
exploration program entirely and all the scientific convenience that might follow.
And if applied 60 years ago, it would have wrecked even the historic Moon landings...
For let's not forget that those early astronauts left "several hundred kilograms
of metabolic waste" at six different sites on the lunar surface. That is, dozens of bags of
excrement, urine, vomit and food waste... Besides making the most historic feat of
human exploration seem more like the "next day" of a student party, the point is that those waste
products could have contained thousands of microbial species. Who's to say that at least
one of them didn't manage to find its own niche in which to reproduce? After all, even the astronauts
of the Apollo 12 mission found bacteria on the moon, surviving a near-vacuum inside the robotic
lander Surveyor 3, which landed on the planet more than two and a half years earlier. If terrestrial
microbes can live in places like that, why not in some of the more habitable parts of Mars?
"BE sure to join the Insane Curiosity Channel...
Click on the bell, you will help us to make products of ever higher quality!"
Unbeknownst or not to the general public, the application of this principle of caution has
been carried out scrupulously over the decades, partly because there has always been a belief
(perhaps illusory) that they could actually sterilize equipment and rovers sent into space.
Now that the human component is about to come back into play, however,
it becomes impossible to meet the same standards. However clean and sanitized it may be,
the human body is loaded with bacteria that risk making it
impossible to carry out a mission, at least according to previous guidelines.
NASA has therefore addressed the issue by downgrading some areas of the Moon (but not Mars),
in order to raise the tolerance limits against human contamination. Specifically, the Moon is now
classified almost entirely as a Category 1 Body (where no protection is required since no life
forms are expected to be found), while previously it was classified as a Category 2 Body (remote
possibility that contamination by terrestrial means could compromise future missions).
This category had been assigned following the formulation of hypotheses regarding the
existence of water masses in an icy state on the Moon, while it is now applied only to a
few very specific sites in which there are shadowed craters that might harbor
icy areas. Most of the Moon thus becomes more easily explored. Regarding Mars, instead, no
modification. The whole planet has been confirmed Category 4 Body (high risk of contamination),
with some specific areas even more protected. A policy so restrictive, this, that makes us
rise more than one suspicion on the possibility that Viking have actually found Martian life, half
a century ago, and that NASA or whoever for it wanted to affix the state secret on the discovery.
Okay, that's a fantasy, maybe. What instead is real is the rise of a part of the scientific
community that declares itself absolutely in disagreement with NASA's overly cautious policy,
and fights for the space agency to vary less strict guidelines,
compatible both with the protection of a possible Martian ecosystem and with the legitimate
explorative aspirations of future human missions. When Earth sends astronauts to Mars, they will
travel with life support and energy supply systems, habitats, 3D printers, food and tools.
None of these materials can be sterilized in the same way that systems associated
with robotic spacecraft can. Human colonists will produce waste,
try to grow food, and use machines to extract water from the soil
and atmosphere. Quite simply, by living on Mars, human colonists will contaminate Mars!
In a recently published article, microbiologist Jose Lopez therefore argues that efforts to
enforce planetary protection provisions are actually completely unnecessary,
and perhaps even very naive. Mars and Earth, in fact, must have been contaminating each
other for billions of years now through the mutual exchange of meteoritic material.
Rather than worrying about contamination, Lopez and his co-authors argue instead that we should
deliberately send our germs into space and that the spread of our microbes should be
part of a larger colonization strategy to change the Martian climate and environment.
In practice, in the article the authors are convinced that it may be impossible to
prevent our germs from invading the places we are exploring, and that it would be therefore
much more rational to start discussing how to use microorganisms to our advantage,
rather than run the risk of putting a brake on colonization for too much caution.
In short, the situation is really difficult, but among the many uncertainties, one thing
is very clear: the implementation of the provisions of planetary protection due to
send astronauts to Mars will raise huge questions between science, engineering,
technology, project management and public policy. Not to mention the ethical issue, which must
be considered as the root cause of all this reluctance to consider the Solar System bodies
as new territories of our complete relevance. Carl Sagan, well known astronomer and popularizer,
claimed that if life was ever found on the fourth planet, then "Mars should belong only to the
Martians, even if they were only microbes". In this perspective, the planet would be
considered an untouchable sanctuary, forbidden forever to the human species.
A display of ethics completely acceptable, but to stand in its motivations should, however, first
confront another holocaust ... that of hundreds of billions of sentient beings killed every
year on Earth for our food vices. Why do Martian microbes deserve to live, and our animals don't?
Meanwhile, the Perseverance rover is about to descend on the red planet. And even in this case,
the main purpose of the mission will not be to rummage through the brackish water springs
and analyze with chemical reagents the presence or absence of microbial life. NO,
the task of the rover will be to collect samples of Martian soil (collected strictly outside the
"special regions") and leave them in the sand in large tubes waiting for other probes come to take
them to Earth. Do you know when? IN TEN YEARS!
What do you think? Doesn't it seem to you that NASA is just trying to stall?