Protect Europa!

Hello, friends!  We’ve reached the end of October, which means we’ve reached the end of Europa month here on Planet Pailly.  We still haven’t determined whether or not Europa is home to alien life, but I hope I’ve persuaded you to take the possibility of life on Europa seriously.

One question that came up a few times this month was whether or not we should send humans to Europa.  The answer, in my opinion, is no.  First off, as we discussed in a previous post, the radiation environment on Europa is crazy dangerous.  We humans would also struggle with the extreme cold and the very low surface gravity.  I’m not saying a colony on Europa is impossible, but there are far safer and easier places we could choose to go.  The neighboring moons of Ganymede and Callisto, for example, would serve as safer and more comfortable bases of operation for humans.

But there’s another reason why colonizing Europa seems like a bad idea to me.  It’s not a science reason.  It’s a legal issue.  There’s an international agreement in place (Article IX of the 1967 Outer Space Treaty) which forbids space agencies like NASA, the E.S.A., or Roscosmos from contaminating other worlds with our Earth germs.  The same agreement also forbids contaminating Earth with germs from other planets.

Some missions are considered riskier than others, contamination-wise.  For example, Article IX doesn’t really apply to NASA’s Parker Solar Probe.  There’s no chance Earth germs will be able to contaminate the Sun (and since the probe will not be returning to Earth, there’s no chance any lifeforms from the Sun could contaminate Earth).  There’s actually a whole risk categorization system in place, with five different categories of risk, and a bunch of sub-categories, too.  Click here if you want to know more details about that.

The important thing for our purposes is that any mission to Europa will involve a very high risk of contamination.  We may not know yet if alien life exists on Europa, but the possibility should be taken seriously.  The people who wrote the Outer Space Treaty made it clear that they’d learned the lessons of history and did not want to repeat the mistakes of the past.  We would not want Earth germs to endanger an alien ecosystem on Europa (nor would we want Europa germs endangering Earth-life).

So for the foreseeable future, I think Europa will be off limits to humans.  Europa might even be declared an interplanetary wilderness preserve, or something like that, and if there’s scientific research to be done on Europa, it can be done remotely from bases on Ganymede or Callisto.

There are easier places in the Solar System for us humans to colonize.  There’s no need for humans to go there.  So unless and until someone shows the contamination risk on Europa is zero, let’s leave Europa alone.


As part of my research for this post, I read the two papers listed below.  If you’re interested in how Earth laws work (or don’t work) in outer space, these papers are worth a look.  Also, if you’re interested in writing Sci-Fi, these papers may get the wheels of your Sci-Fi writer brain turning.

Contaminating Mars

The story I’m about to tell is a work of fiction, but it could very well happen in reality one day.  If it did, it could cause an enormous scandal in the scientific community, ruin what remains of NASA’s reputation, and end the careers of anyone directly involved.


The year is 2020.  NASA’s latest Mars rover, Intrepid, has landed successfully and wheeled around a bit, proving that all its systems are functioning.  Intrepid’s predecessor, the Curiosity rover, found evidence in 2013 that life could exist on Mars, but Curiosity wasn’t equipped to test if any life forms do exist there.  Intrepid’s mission is to follow up on Curiosity’s work.

NASA engineers have equipped Intrepid with state-of-the-art biochemical research equipment.  They gave it new technology that wasn’t available when Curiosity was launched, as well as delicate, new digging tools for collecting soil samples.  Scientist carefully selected Intrepid’s landing site, putting it near what they believe is subsurface liquid water melting from one of Mars’s polar ice caps.

Intrepid begins its work, and the very first test comes back positive.  There’s bacterial life on Mars!  Scientists around the world celebrate.  The media goes crazy, and the old theory that life on Earth began on Mars is revived once again when someone notices similarities between the DNA of the Martian microbes and that of life on Earth.  In fact, the Martian bacteria seem to have a lot in common with E. coli.

But the next test shows fewer bacteria.  The one after that shows fewer still, and soon no bacteria can be found at all.  It seems the “Martian” bacteria aren’t capable of surviving on Mars.  Soon, the truth comes out.  One of those delicate digging tools was opened before it left, meaning it may have been contaminated.  Previous studies have already shown that E. coli might be able to survive in space if shielded from ultraviolet radiation.

End of story.

Currently, the United States is part of an international agreement called the Outer Space Treaty, which stipulates that any probe we send to another planet must be thoroughly decontaminated.  NASA even has a Planetary Protection Officer, Dr. Catherine Conley, in charge of making sure that we don’t introduce invasive species to alien worlds.  The point of all this is not only to protect alien ecosystems (if they exist) but to ensure that if we do discover life on another planet, we’ll know for certain that its genuine alien life and not something that stowed away on our own space vehicles.

And yet despite the Outer Space Treaty, despite NASA’s own rules and Dr. Conley’s best efforts, one of Curiosity’s digging apparatuses was opened and potentially contaminated before it left Earth in 2011.  Could any bacteria have survived the long journey to Mars?  We don’t know.  It’s possible.  So far it doesn’t seem like any harm was done, but this could be a costly mistake if it ever happens again.