Colonizing Mars means contaminating Mars – and never knowing for sure if it had its own native life

November 6, 2018 by David Weintraub, The Conversation
Once people get there, Mars will be contaminated with Earth life. Credit: NASA/Pat Rawlings, SAIC, CC BY

The closest place in the universe where extraterrestrial life might exist is Mars, and human beings are poised to attempt to colonize this planetary neighbor within the next decade. Before that happens, we need to recognize that a very real possibility exists that the first human steps on the Martian surface will lead to a collision between terrestrial life and biota native to Mars.

If the red planet is sterile, a human presence there would create no moral or ethical dilemmas on this front. But if life does exist on Mars, human explorers could easily lead to the extinction of Martian life. As an astronomer who explores these questions in my book "Life on Mars: What to Know Before We Go," I contend that we Earthlings need to understand this scenario and debate the possible outcomes of colonizing our neighboring planet in advance. Maybe missions that would carry humans to Mars need a timeout.

Where life could be

Life, scientists suggest, has some basic requirements. It could exist anywhere in the universe that has liquid water, a source of heat and energy, and copious amounts of a few essential elements, such as carbon, hydrogen, oxygen, nitrogen and potassium.

Mars qualifies, as do at least two other places in our solar system. Both Europa, one of Jupiter's large moons, and Enceladus, one of Saturn's large moons, appear to possess these prerequisites for hosting native biology.

I suggest that how scientists planned the exploratory missions to these two moons provides valuable background when considering how to explore Mars without risk of contamination.

Cassini shot this false-color image of jets erupting from the southern hemisphere of Enceladus on Nov. 27, 2005. Credit: NASA/JPL/Space Science Institute, CC BY

Below their thick layers of surface ice, both Europa and Enceladus have global oceans in which 4.5 billion years of churning of the primordial soup may have enabled life to develop and take root. NASA spacecraft have even imaged spectacular geysers ejecting plumes of water out into space from these subsurface oceans.

To find out if either moon has life, planetary scientists are actively developing the Europa Clipper mission for a 2020s launch. They also hope to plan future missions that will target Enceladus.

Taking care to not contaminate

Since the start of the space age, scientists have taken the threat of biological contamination of other worlds seriously. As early as 1959, NASA held meetings to debate the necessity of sterilizing spacecraft that might be sent to other worlds. Since then, all planetary exploration missions have adhered to sterilization standards that balance their scientific goals with limitations of not damaging sensitive equipment, which could potentially lead to failures. Today, NASA protocols exist for the protection of all solar system bodies, including Mars.

Since avoiding the biological contamination of Europa and Enceladus is an extremely well-understood, high-priority requirement of all missions to the Jovian and Saturnian environments, their moons remain uncontaminated.

NASA's Galileo mission explored Jupiter and its moons from 1995 until 2003. Given Galileo's orbit, the possibility existed that the spacecraft, once out of rocket propellant and subject to the whims of gravitational tugs from Jupiter and its many moons, could someday crash into and thereby contaminate Europa.

Cassini’s ‘Grand Finale’ ended with the spacecraft burning up in Saturn’s atmosphere.

Such a collision might not occur until many millions of years from now. Nevertheless, though the risk was small, it was also real. NASA paid close attention to guidance from the National Academies' Committee on Planetary and Lunar Exploration, which noted serious national and international objections to the possible accidental disposal of the Galileo spacecraft on Europa.

To completely eliminate any such risk, on Sept. 21, 2003, NASA used the last bit of fuel on the spacecraft to send it plunging into Jupiter's atmosphere. At a speed of 30 miles per second, Galileo vaporized within seconds.

Fourteen years later, NASA repeated this protect-the-moon scenario. The Cassini mission orbited and studied Saturn and its moons from 2004 until 2017. On Sept. 15, 2017, when fuel had run low, on instructions from NASA Cassini's operators deliberately plunged the spacecraft into Saturn's atmosphere, where it disintegrated.

But what about Mars?

Mars is the target of seven active missions, including two rovers, Opportunity and Curiosity. In addition, on Nov. 26 NASA's InSight mission is scheduled to land on Mars, where it will make measurements of Mars' interior structure. Next, with planned 2020 launches, both ESA's ExoMars rover and NASA's Mars 2020 rover are designed to search for evidence of life on Mars.

The good news is that robotic rovers pose little risk of contamination to Mars, since all spacecraft designed to land on Mars are subject to strict sterilization procedures before launch. This has been the case since NASA imposed "rigorous sterilization procedures" for the Viking Lander Capsules in the 1970s, since they would directly contact the Martian surface. These rovers likely have an extremely low number of microbial stowaways.

The Curiosity rover was tested under clean conditions on Earth before launch to prevent microbial stowaways. Credit: NASA/JPL-Caltech, CC BY

Any terrestrial biota that do manage to hitch rides on the outside of those rovers would have a very hard time surviving the half-year journey from Earth to Mars. The vacuum of space combined with exposure to harsh X-rays, ultraviolet light and cosmic rays would almost certainly sterilize the outsides of any spacecraft sent to Mars.

Any bacteria that sneaked rides inside one of the rovers might arrive at Mars alive. But if any escaped, the thin Martian atmosphere would offer virtually no protection from high energy, sterilizing radiation from space. Those bacteria would likely be killed immediately. Because of this harsh environment, life on Mars, if it currently exists, almost certainly must be hiding beneath the planet's surface. Since no rovers have explored caves or dug deep holes, we have not yet had the opportunity to come face-to-drill-bit with any possible Martian microbes.

Given that the exploration of Mars has so far been limited to unmanned vehicles, the planet likely remains free from terrestrial contamination.

But when Earth sends astronauts to Mars, they'll travel with life support and energy supply systems, habitats, 3-D printers, food and tools. None of these materials can be sterilized in the same ways systems associated with robotic can. Human colonists will produce waste, try to grow food and use machines to extract water from the ground and atmosphere. Simply by living on Mars, human colonists will contaminate Mars.

Can't turn back the clock after contamination

Space researchers have developed a careful approach to robotic exploration of Mars and a hands-off attitude toward Europa and Enceladus. Why, then, are we collectively willing to overlook the risk to Martian life of human exploration and colonization of the ?

Scientists hypothesize that dark narrow streaks were formed by briny liquid water – necessary for life – flowing down the walls of a crater on Mars. Credit: NASA/JPL-Caltech/Univ. of Arizona, CC BY

Contaminating Mars isn't an unforeseen consequence. A quarter century ago, a National Research Council report entitled "Biological Contamination of Mars: Issues and Recommendations" asserted that missions carrying humans to Mars will inevitably contaminate the planet.

I believe it's critical that every attempt be made to obtain evidence of any past or present life on Mars well in advance of future missions to Mars that include humans. What we discover could influence our collective decision whether to send colonists there at all.

Even if we ignore or don't care about the risks a human presence would pose to Martian life, the issue of bringing Martian life back to Earth has serious societal, legal and international implications that deserve discussion before it's too late. What risks might Martian life pose to our environment or our health? And does any one country or group have the right to risk back contamination if those Martian lifeforms could attack the DNA molecule and thereby put all of life on Earth at risk?

But players both public – NASA, United Arab Emirates' Mars 2117 project – and private – SpaceX, Mars One, Blue Origin – already plan to transport colonists to build cities on Mars. And these missions will contaminate Mars.

Some scientists believe they have already uncovered strong evidence for life on Mars, both past and present. If life already exists on Mars, then Mars, for now at least, belongs to the Martians. Mars is their planet, and Martian would be threatened by a human presence there.

Does humanity have an inalienable right to colonize Mars simply because we will soon be able to do so? We have the technology to use robots to determine whether Mars is inhabited. Do ethics demand that we use those tools to answer definitively whether Mars is inhabited or sterile before we put human footprints on the Martian surface?

Explore further: Interpreting new findings of methane on Mars

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eachus
3.8 / 5 (4) Nov 06, 2018
When a TV reporter was interviewing Wernher von Braun while waiting for the Apollo 11 astronauts to set foot on the moon. He asked if Wernher thought there was life on the moon.

"Life on the moon? Of course there is life on the moon. We just put it there."

That's sort of my feeling about life on Mars. If we put it there, the question of whether it was there earlier becomes much less interesting. Also, there was an article in Analog many years ago about cells found on astronomical plates exposed when Venus was in a certain position relative to Earth. Could they have come from Venus? Sure growing in the upper layers of Venus' atmosphere would make the trip through interplanetary space relatively easy. But if they came from Venus, did life in the Solar System start there? Good question.

In the case of Mars, we have Martian rocks which landed on Earth, did some rocks go the other way? Likely. We might find Earth life on Mars in spite of the most perfect decontamination.
guptm
1 / 5 (3) Nov 06, 2018
Colonize Antarctica first and prove that you have everything to do this. Is it not much easier to colonize Antarctica than Mars? Do not take actions based on stupidity.
Mimath224
1 / 5 (2) Nov 06, 2018
Well one thing is for sure is that if we do/are able to colonize Mars we couldn't be blamed for deforestation etc., that is on the surface anyway.(what is under the surface is a wait and see scenario). But we are likely to take our greed and adverse characteristics there too...just wonder how long it would be before a war breaks out. Come to think of, how long before they would want independence from Earth, Ha!
TheGhostofOtto1923
2.8 / 5 (4) Nov 06, 2018
"a collision between terrestrial life and [POSSIBLE] biota native to Mars."

-The author assumes that life that evolved to thrive in complex ecosystems on earth would be better at surviving on mars than life that evolved specifically to thrive there. Why?

He also seems to be assuming that life would exist everywhere on mars or that earth life, once introduced, would spread unchecked. If that's true then it's already too late.

Chances are that neither would threaten the other. We will be establishing earth-type ecologies, probably underground, that mars life would probably eschew.
But we are likely to take our greed and adverse characteristics there too
Man I hate human-haters.
eachus
5 / 5 (2) Nov 06, 2018
Colonize Antarctica first and prove that you have everything to do this. Is it not much easier to colonize Antarctica than Mars? Do not take actions based on stupidity.


Technically we haven't colonized Antarctica due to a treaty signed a long time ago. Anything the signatories take to Antarctica, they have to bring home eventually. But there are probably more people there year round than Europeans during the first few decades of colonizing America.

Colonizing the moon may be harder than colonizing Mars, but there are a lot of good reasons to do it first. (The next generation of large telescopes--beyond the one building now, really should be on the Moon, and pairing radio telescopes there with arrays on Earth should allow for amazing resolution. Yes, it would help to have more locations, and some of those can more be easily communicated with from the Moon.)
TheGhostofOtto1923
1 / 5 (4) Nov 06, 2018
colonize Antarctica
We already have.

"The Amundsen–Scott South Pole Station is a United States scientific research station at the South Pole, the southernmost place on the Earth... In 1992, the design of a new station began for a 7,400 m2 (80,000 sq ft) building with two floor levels that cost US$150 million.[11] Construction began in 1999, adjacent to the Dome. The facility was officially dedicated on January 12, 2008... 200 people already... a modular design, to accommodate an increasing station population, and an adjustable elevation, in order to prevent the station from being buried in snow..."
Technically we haven't
Try google before posting garbage.
Mimath224
not rated yet Nov 06, 2018
"a collision between terrestrial life and [POSSIBLE] biota native to Mars."

-The author assumes that life that evolved to thrive in complex ecosystems on earth would be better at surviving on mars than life that evolved specifically to thrive there. Why?

He also seems to be assuming that life would exist everywhere on mars or that earth life, once introduced, would spread unchecked. If that's true then it's already too late.

Chances are that neither would threaten the other. We will be establishing earth-type ecologies, probably underground, that mars life would probably eschew.
But we are likely to take our greed and adverse characteristics there too
Man I hate human-haters.

Ha, I admire the human race for many things but the reality is that we'll fight over many things too. That isn't likely to change just because of a Mars (or any other) colony.
Ken_Fabian
5 / 5 (1) Nov 07, 2018
I think it is unlikely we will colonise Mars - there is no sound economic basis for doing something so difficult and expensive; no commercial opportunities beyond broadcast rights, no possibility of material trade. Self reliance is going to be very difficult - the SpaceX "plans" just won't do it, and true self sufficiency is something that, at the least, requires an advanced industrialised economy on the scale of a small nation. Earth repopulating a succession of extinct Mars colonies is far more likely than Mars colonies surviving to repopulate an extinct Earth.

We might see Man on the Moon type there and back missions - for national pride with a side serve of science, with looking for life a likely mission goal. As long as such missions do have protocols for limiting cross contamination, they will probably get the go-ahead. Returns may have to endure quarantine. I don't really expect to see it - an orbit and return is more doable, perhaps dropping robotic probes.
guptm
1 / 5 (1) Nov 08, 2018
I would respectfully disagree that setting up a research station at Antarctica could be called colonization. The word colonization originates from Latin 'colere' which means 'to inhabit'.

We can certainly set up a research station at Mars, but it cannot be called colonization. Have we colonized low earth orbit where we have a research station?
TheGhostofOtto1923
1 / 5 (3) Nov 09, 2018
I would respectfully disagree
Of course you would.
that setting up a research station at Antarctica could be called colonization. The word colonization originates from Latin 'colere' which means 'to inhabit'
The latest Amundsen–Scott South Pole Station has been continuously inhabited for 19 years. It is intended to be permanent.

The first US colony was at Jamestown, started with 105 colonists. It was briefly abandoned after 18 years. It was for a long time totally dependent on support from europe and indigenes.

The Roanoke Colony was a failed colony. Nevertheless it was a colony.

You dont consider the amundsen colony a colony because you didnt bother to research what a colony is, because your rather pretend you're right rather than admit you were wrong.

The first mars colony will strive to be self-sufficient but, like the US colonies or colonies in general, will rely on outside support for a long time.
TheGhostofOtto1923
1 / 5 (3) Nov 09, 2018
Have we colonized low earth orbit where we have a research station?
?? What does that have to do with anything?? How many research stations can you find in areas already inhabited?

Heres one
"Kuroshima Research Station in Kuroshima, Okinawa."
guptm
1 / 5 (1) Nov 09, 2018
What is the correct meaning and definition of colonization?

International Space Station has been continuously inhabited by humans for 20 years. Can ISS be called colonized?

Some examples of colonies are: British colonies in India, Spanish colonies in North and South America, Dutch colonies in Asia, French colonies in Africa, Portuguese colonies in South America.

To me colonies means, a self-sufficient living in a new place by replacing or co-living with indigenous population, if existent.

Are we self-sufficient in Antarctica or at ISS? Can a common man live there?
TheGhostofOtto1923
1 / 5 (3) Nov 09, 2018
What is the correct meaning and definition of colonization?
Jesus christ. Why the hell dont you try googling it?
To me colonies means
Doesnt matter what it means to you. It has a universally accepted definition that is easy to find.
a self-sufficient living in a new place by replacing or co-living with indigenous population, if existent
-none of which applies.
Are we self-sufficient in Antarctica or at ISS?
I told you that the first north american colonies werent self sufficient.
Can a common man live there?
What do you mean by that? You think the pros there cook their own food, wash their own clothes, or fix the things that break?

Youre sitting there imagining all this stuff when all you have to do is LOOK IT UP. Are you that lazy?

Youtube has video tours of the station if you dont want to read.

Thing is, everything they do at amundsen station is directly appicable to a mars colony. They even grow some of their food there.
guptm
not rated yet Nov 09, 2018
All the best with your knowledge. I clearly see your limits.

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