As we send rovers and landers to other worlds, we have to think about the tiny microbial astronauts we’re sending along with us. In fact, NASA is so concerned about infecting other worlds that it has established the planetary protection protocols. Just to be safe.
Mars is the world we are most concerned about at this point – it has the strictest protocols. Enceladus and Europa are also being upgraded as missions are being considered and planned.
United Nations Outer Space Treaty
interplanetary contamination –Forward contamination is the transfer of viable organisms from Earth to another celestial body. Back contamination is the transfer of extraterrestrial organisms, if such exist, back to the Earth’s biosphere.
Mars 2020 mission prep
Fraser Cain: Astronomy Cast, Episode 514: Planetary Protection Protocols. Welcome to Astronomy Cast, our weekly facts-based journey through the cosmos. Where we help you understand not only what we know, but how we know what we know.
I’m Fraser Cain, publisher of Universe Today, with me as always, Dr. Pamela Gay, a senior scientist for the Planetary Science Institute, and the director of Cosmo Quest. Hey Pamela, How ya doin’?
Dr. Pamela Gay: I’m doing well, how are you doing, Fraser?
Fraser: I’m doing great. Although, hating technology, which was a conversation that we just had. That’s just –
Dr. Gay: It happens.
Dr. Gay: It evolves quickly, and sometimes sideways.
Fraser: Yeah, exactly. So, I may send a little different in my audio this time, and that’s just because I’ve had to make some changes to the way have got my audios. The way it’s recording. I don’t know if it’s gonna be better, worse. I guess we’ll find out. Do you have to shamelessly self-promote this week?
Dr. Gay: Yes, go to AstroTours.co/starstryder and sign up to spend late August; August 22 through the 29th with me touring through the American Southwest going to great observatories, seeing great landscapes. My favorite landscapes in the world. Hey, there might even be Vegas baby, involved. So, please, please go tour the countryside. This is where I spent my summers growing up, so there’s going to be lots of stories to tell.
Fraser: That sounds great. All right, so when we send rovers and landers to other worlds. We have to think about the tiny microbial astronauts were sending along with them. In fact, NASA is so concerned about infecting other worlds that it has established the planetary protection protocols, just to be safe.
Pamela, how on earth, or how in space is it possible for microbes to be a problem if we send spacecraft to other worlds?
Dr. Gay: Some things do not want to die. That’s the fundamental issue.
Dr. Gay: We die easily. You put us in space we die. Put a Tardigrade in space, put any of a bazillion other extremophiles, microbes, bacterium in space, and they live on, and on, and on and just might choose to live on; on another world where they kill any and all indigenous life.
Fraser: Do we have any examples of life, demonstrating that space is no problem for it?
Dr. Gay: Yeah, that Tardigrade I mentioned. They also go by the name Water Bear. They are extremely cute they kinda look like; if you’ve watched the cartoon version of “The Last Airbender”, which is the only version you should watch.
Dr. Gay: They kind of look like Appa, less fur, more sucky cuteness. But, just like the Tardigrade that appeared in “Star Trek – Discovery”, they have the ability to push all the water out of their bodies, encapsulate themselves, and just stop respiration for a while. In protective state, they can withstand going to space returning from space, being in space, and then returned quite happily to life when exposed to the correct circumstances.
Fraser: Then of course, one of the other great stories is when the astronauts flew to the moon, during the Apollo missions, they brought back the camera from one of the landers; that had already been on the moon for a while, and what do you know, bacteria, and are able to revive it. But, there is a bit of controversy so don’t send me that email, that some people believe that it actually wasn’t life that had survived the journey that, in fact, it had been re-contaminated here on earth.
So, there’s a bit of a scientific controversy, but I like the one what sounds like life can totally handle being on the moon and back.
Dr. Gay: Me too.
Fraser: Yeah. Okay, so we know, but I need the point is, they have been tests on earth, they’ve freeze-dried them, put them in vacuum. They have made the cold, made them hot –
Dr. Gay: Radiated them.
Fraser: – radiated them. Just insulted them and they’ve been able –
Dr. Gay: They don’t die when you call them names. It just doesn’t work.
Fraser: Yeah, neither sticks nor stones, nor names. So, yeah we know that bacteria and some of these tiny little lifeforms can handle pretty extreme environments. Okay, great. So, what does that mean then?
Dr. Gay: Well, that means that the world has been trying to figure out exactly how to handle this for quite some time. There was an original United Nations set of recommendations that that were put together back in 1959. It’s handled – it’s governed by COSPAR, this is the Committee on Space Research, and in 1964 they issued a resolution, and I’m gonna read it here:
This is resolution 26 and it, “– affirms the search for extraterrestrial life is an important objective space research, that the planet of Mars may offer the only feasible opportunity…” This was written in 1964.
“– the only feasible opportunity to conduct this search during the foreseeable future, that contamination of this planet would make such a search far more difficult, and possibly even prevent, for all time an unequivocal result, that all practical steps should be taken to ensure that Mars be not biologically contaminated, until such time as this search has been satisfactorily carried out, and that cooperation in proper scheduling of experiments –” and it goes on and on.
What it boils down to is; hey, we have this planet, Mars – 1964 – it’s the only place we know of – because it was 1964 – that might have life, let’s not send smallpox blankets.
Dr. Gay: It was understood that when Europeans came to the New World, we kinda like killed a lot of stuff, by which I mean, lots of tribes of advanced humans with cool civilizations, and writing and architecture, and arts and –
Dr. Gay: We flipped them all off with disease.
Fraser: And, not just disease. I mean we’re dealing with the invasive species; were dealing with rats and various kinds of plants and things that are really hard on our local environment, and they push out though the local creatures. That’s the risk is that, you may go and find life on Mars, but it turns out you just found rats and –
Dr. Gay: Exactly.
Fraser: – and Japanese knotweed.
Dr. Gay: Or, if you live here, stinkbugs.
Fraser: Stinkbugs, those are yours, yeah.
Dr. Gay: Yeah, Japanese stinkbugs.
Fraser: We have knotweed. I’m trying to think what our bug is; thistles and –
Dr. Gay: Yeah.
Fraser: – and the Himalayan blackberries.
Dr. Gay: At least those are tasty.
Fraser: Super tasty yeah, yeah. I don’t mind that invasion, but apparently the local plant life doesn’t. So, you can imagine some situation where we go Mars and we find – we perform this enormous, difficult, complicated mission to get spacecraft down to the surface of Mars; and the rover digs down, and retrieves a sample, and does some kind of experiment and finds that there is life there, and it turns out that it was just earth life, that had made it to Mars.
In fact, now Mars is filled with earth life. Any Mars life was there is now harder to find.
Dr. Gay: So, to try and prevent this fate which you describe. They have, by which I mean – COSPAR, The United Nations committees, NASA has signed on – have set out a group of different categories of missions that require, per international treaty, cleaning at different levels. So for instance, if you’re just doing what’s called a category one mission; this is a flyby, an orbiter or a lander on an undifferentiated metamorphized asteroid, or other such life not gonna be here, kind of object, you’re good, don’t worry about it.
This is where Bennu is going to go grab a rock – we didn’t really put a lot of effort into sterilizing OSIRIS-REx, but it’s just a lump of rock. We’re gonna grab smaller rock off of the bigger rock. We’re gonna bring it home, and no one’s worried. In the vastness of time, the ultraviolet light of the sun has killed everything. We’re good.
Fraser: Right, so don’t worry about sending a spacecraft. Don’t worry about how well you washed OSIRIS-REx. You’re not going to infect Bennu, as you can lightly pluck a rock off the surface of the of the asteroid, and then scoot back home.
Dr. Gay: Exactly. So, these are the don’t worry missions. Now, category two is where maybe you worry a little. This is flyby’s, orbiters, landers of objects that we really can’t imagine how life might exist. So, this is stuff like comets; differentiated, carbonaceous, condroid asteroids, Jupiter, Saturn, Uranus, Neptune. These are worlds where probably we don’t have life. Now, what’s fascinating is when you look at older PowerPoint presentations about this, you start to see things like Titan listed here, Ceres listed here.
These are objects that we are now realizing, oh expletive! They might just have life. So, we have to periodically update our PowerPoints.
Fraser: Right, in fact, when we look at Europa and Enceladus, and as you said, Titan and maybe even Pluto and Eris, and planet nine, when we find it. The upper cloud tops of Venus, and permanently shadowed craters – well, maybe not Mercury.
Dr. Gay: Probably not.
Fraser: So, we’ve got a more rigorous cleaning. You gotta wash your spaceship a little better.
Dr. Gay: Yeah, it’s one of these things where you should take general care. They actually have guidelines, and numbers of – there’s a specific bacteria that really likes to leave spores everywhere that they use as a tracing bacterium. So, this is where everything is made in a clean lab. They wipe everything down with alcohol as they go. But, it’s not a huge concern.
Fraser: Right, right. They’re doing the best they can, as they construct the spacecraft. They’re trying to minimize the amount of bacteria that ends up on anything, but they’re not losing sleep at night if they miss a few. There are absolutely going to be bacteria coming along for the ride, just not as many as if you just built your spaceship in the in the garage and just and sent it to – out into space.
Dr. Gay: Then, as we continue down this list we look at more and more dangerous situations. As we get to category three where now were talking about flybys of things that could have life, Mars, Europa and Enceladus.
This is where we – the way they phrase it is orbiter missions to a target body of chemical evolution, and or origin of life interest. It’s the opinion of the scientific body that every chance of contamination which could compromise future investigations be taken. So basically, if ya might crash into it, try to make sure that you’re clean, but it’s the how clean you need to be in case you crash, not that how clean your going to be because you’re going to be running experiments, specifically where life is likely to be.
Fraser: Right. So, an example that might be something like Cassini where it was intended to fly around –
Dr. Gay: Or, Galileo is exactly the right example to use; where they plunged it purposefully into Jupiter at the end of the mission, and that was planned, because Europa.
Fraser: Right, so it didn’t have the level – it wasn’t gonna be going down and drilling into the ice on Europa, and looking for Europan space whales. It was going to be orbiting Jupiter in an environment where under some weird combination of chances it could end up smashed on the surface of Europa, and somehow contaminate Europa. So, might as well ditch it into Jupiter just to be safe.
Dr. Gay: Then, we start getting into the; okay to think really hard about this because were going somewhere potentially dangerous but not worst casing it. So, this is where you start having category four lander missions on these worlds that just might have life. This is Mars, Europa and Enceladus.
So, here you bake it, you radiate it, you wipe it down, you hope, you chemical. One of the things that we’re running into is this is where we have experience; this is the Viking missions. The Viking missions went to Mars, knew full well that they were looking for a life, that they didn’t know if where they were landing could have life. So, what they did was they literally baked the spacecraft. They put them in a fancy oven, raised the temperature up 115 degrees Celsius above the boiling point, and it just baked them for hours.
Dr. Gay: And, the reason they did this was. There was no life they could think of that could survive this baking. This was early, we now know better –
Fraser: That was then, right. We know better. Just to digress briefly, this is – sort of part of the problem is that there’s all kind of Russian, or Soviet, and even American spacecraft that are in all kinds of potentially sensitive locations, or have just crashed onto Mars; that had no cleaning done whatsoever. So, if this was possible, then it’s possible that we have already ruined Mars.
Dr. Gay: It’s true, it’s true.
Fraser: But, that’s future exobiologist problem, not ours.
Dr. Gay: So, here we start worrying, especially with things like the Mars 2020. Okay, so were going there. We’re gonna to be looking for life, we cleaned our spacecraft as well as we can; but processes like baking, those kill everything – that you could still be covered with dead life, and how is that going to affect our experiments. So, we have to make sure that we don’t just kill it all, but we remove the carcasses.
Fraser: Right, it got really morbid really fast.
Dr. Gay: It got really morbid really fast, and this is getting much more difficult to do, and the National Research Council here in the United States has actually put out a plan. It came out last summer, where they called for scientists to rethink how it is that we define these categories. Rethink what it is we use as our – is this clean enough model, and consider how do we deal with the fact that now we have instruments that we can’t radiate, because they’re sensitive.
We have things we certainly can’t heat up, because their plastic, or made out of epoxies that will melt. How do we deal with atom thick films, and detectors that really can’t tolerate anything except for good alcohol swiping. As we develop more and more fragile and sensitive technologies, our ability to clean things goes down rapidly, so they’re working on trying to define new ways to clean things. This is now where were arguing over things. We haven’t even gotten the worst possible scenarios.
Fraser: Yeah, the most extreme one.
Dr. Gay: This is where we go, and we grab a sample from someplace that could harbor life. This is – we send a rover to do the rover equivalent of walking up to one of those dark streaks on Mars, if their real, I understand there’s debate – grab a sample of dark soil and bring it home. This is where we go to Europa we drill down we grab some fluid. There is no plans to do this anytime in the near future. We bring it back.
Take All these kinds of go forth, grab biologicals, maybe, and bring them home missions. These are the category five. They get shifted into restricted earth return, and unrestricted earth return based on how hazardous these worlds are. So –
Fraser: You’ve got sort of a double problem, right. You got the problem that as you dig into a sample; say you got this really interesting salty brine that you find on Mars, and you dig into it with your scoop to grab a sample to bring home. You could be contaminating it with whatever earth bacteria is on the scoop, and then you bring that material home; and now you got the risk contaminating Earth with whatever material you found on Mars. So, two planets are at risk now.
Dr. Gay: This is referred to as forward contamination where we take and we contaminate forward, and backward contamination where we bring things back. In dividing up each of these categories, the categories really are; what is the risk to the world, and what is the risk for us.
So, category one is no risk, because there’s probably not life there, and we’re not bringing anything back. This is the flyby, the orbit, the land on boring space rocks. This is OSIRIS-REx at Bennu. Category five, with the return missions, still getting divided up, where we’re bringing back samples from the moon, which we’re pretty sure is dead, so we’re careful, but we’re not – it’s not Andromeda strain we’re worried about,
Dr. Gay: Whereas, with those restricted earth returns from Mars, Europa, and Enceladus it is exactly the Andromeda strain that we are worried about.
Fraser: Right, and we think about how life here on earth has evolved perfectly with this sort of mutual arms race, and so people wonder could you get infected by bacteria from Mars; could you get a virus from Mars, and I don’t see that as being the big risk. You’re going to – you have not encountered it at all. It has no real pathways.
There are lots of viruses that have – you can’t catch viruses that infect insects because they’ve evolved to find their way into insects, not into us, but it’s that issue of having these life forms that can fill these ecological niches that we have, that it could be the bigger risk.
When you think about some poor bacteria on Mars that’s lived in a brutal environment. Trying to survive near a perchlorate soil with ultraviolet radiation beaming down on it where the air pressure is low, and all it has two breathe is carbon dioxide. Then, you bring it to Earth, and it just goes like, this place is a paradise, compared to the horrible nightmare world that I used to live on.
Dr. Gay: It may require perchlorates; it may require a nightmare to live within –
Fraser: Maybe, or was evolved to handle the most extreme environments we can possibly imagine, but the point is, let’s not find out.
Dr. Gay: The other side of this is as we are sitting here saying, “Maybe.” The reason we say maybe it’s because the universe keeps proving itself to be more creative than we give them credit for. And, this has become a major argument where we have people saying that since the universe likes to rain meteorites on our heads, cars, warehouses and everything else, and these meteorites, in many cases are coming to us from Mars.
Not every case, not a majority of cases, but frequently enough that even people like me have their own sample of Mars rock that came from a Mars meteorite.
And the argument is that if all of these Mars rocks can come to Earth, and we haven’t died yet, do we really need to worry. The National Research Council, in pulling together the top minds to think about this argument, has basically said, “Yes, yes! We need to worry.”
Because, these meteorites, in general, while there still raining on the Earth they were generated during a handful of collision events that occurred eons ago; probably during the age of the great heavy bombardment. They’ve been floating around in space for a good long time before they hit our planet. They were essentially already baked, or radiated, frozen, melted everything else.
And, then they went through our atmosphere. So, that probably would’ve killed whatever was on them. But, if we’re going to these – hasn’t been blasted into space in a massive collision millions of years to billions of years ago – if we’re instead just digging in a nice briny mud pit beneath the surface –
Dr. Gay: – we may find that thing capable of killing us that we’re not –
Dr. Gay: – creative enough to know could be there.
Fraser: All I know is that we don’t think of the consequences, the onion, we never see all of the unintended consequences and if there is one thing that we can always predict is that there will be unintended consequences –
Dr. Gay: Yes.
Fraser: – of any action that we do. Like that alone, I’m sure whatever terrible person brought scotch broom here to Vancouver Island thought it would be lovely to have a little piece of Scotland in their garden, on Vancouver Island. Couldn’t imagine this stuff just everywhere on our whole island, killing everything. It’s the worst.
Dr. Gay: Exactly.
Fraser: I know your instinct is; what’s the worst that could happen? And, the answer is, you don’t know, let’s not find out. Let’s just be careful, it’s just the smart move.
Dr. Gay: Yes, it’s always cheaper to prevent than to clean up.
Dr. Gay: So, let’s be cautious now, and not kill –
Dr. Gay: – everything later.
Fraser: This is a total rabbit hole. But, apparently now looking at desalination plants. There is like tens of thousands of desalination plants that are dumping toxic brine back –
Dr. Gay: Right.
Fraser: – the oceans, and wiping out local environments – that’s collecting down at the bottom of the oceans and causing problems to coastal habitats. We wouldn’t have thought – we thought well, the ocean is limitless, there’s no way we could extract enough and return enough salt to cause – well, turns out you can. So, your idea of let’s just grab all the water from the oceans; actually, now we got a problem. So, again, just unintended consequences.
Dr. Gay: Well – yeah.
Fraser: I know I started this rabbit hole, but the point being unintended consequences. So, we clean; what else can we do?
Dr. Gay: Not crash. This is where we have problems, and this is where when you look at the categories, you have the categories that are for landing missions on Mars, Europa, and Enceladus; category four. Then, you have the category for flying and orbiting, and sometimes our orbiters don’t stay up. Sometimes, our flybys fly into instead. Some will crash. Bottom line, just don’t crash.
Fraser: Right, that’s it. That’s your plan is to plan on not crashing. Right.
Dr. Gay: Yeah, it’s cheaper.
Fraser: So, do you –
Dr. Gay: Plus you get more science.
Fraser: Will there be a time when these kinds of planetary protections are no longer required? Can you imagine sometime in the far future where we have either found life, or found no life to the point we’re like, okay, that’s it it’s all dead, and we just don’t care anymore?
Dr. Gay: This is where it gets tricky. If we find life, I want to believe – and I know I’m being a Pollyanna here – I want to believe that if we find that there is life of some form, that we will go, “Okay, we’re good. We’re gonna watch this we’re gonna let it advance. We’re gonna learn from whatever, go science,” and we will limit our interactions to sealed habitats; go land on Phobos, and not on mars. I’m probably wrong.
Fraser: Yeah, super wrong. I mean there’s no way –
Dr. Gay: I know, I know.
Fraser: – there’s no way that people – like you imagine you get the astronauts living – even on science station on Mars, and they are living in their tunnels underground. Regretting, this research expedition, but they’re gonna want one taste of the sun, and they’re gonna put on their spacesuit, and they’re gonna walk out onto the Martian surface and just be shaking out microbes into the soil. So, once we get serious about moving to, living on, exploring. What are we now, 2024?
“We’re only five years away from space extending those first human colonists hundreds of time to the surface of Mars,” he says sarcastically.
Dr. Gay: The one – two things it gives me hope. The first is we’re not gonna get there by 2024. The second is in designing upcoming rovers and spacesuits; one of the big new design concepts that they’ve been testing out with the Desert RATS program out in the desert is; the spacesuits, essentially are attached outside of your spacecraft. The reason is to prevent dust and grime from getting into the spacecraft. So, you slide down into your spacesuit and climb back up; a hatch closes in your helmet sealing you in, and then you reattach yourself later.
So, the outside of your suit is never touched by you, it only touches the outside world. The stuff on the outside suits never gets into your spacecraft. I’m hoping that as we create more and more of these novel designs, that we’ll be able to reduce our interactions with the outside world, and we may need to take lessons from archaeology as well.
It is becoming the norm that when we find new and awesome archaeological sites, we don’t dig them up the same way that we used to. We instead use ground-penetrating radar, we use MRIs, we use whatever technology allows us to look in –
Dr. Gay: – without disturbing the samples.
Dr. Gay: Hopefully, we will figure out ways to do the same sort of remote sensing for life.
Fraser: Well, I hope we get to this place in the future where it actually is a problem, right? Like we do find life, and we’re so glad we were careful, or that we do bring samples back and we find life like wouldn’t that be the greatest thing. All right, well thank you so much Pamela and I will talk to you next week.
Dr. Gay: Sounds great Fraser, talk to you later.
Announcer: Thank you for listening to Astronomy Cast, a non-profit resource provided by the Planetary Science Institute, Fraser Cain, and Dr. Pamela Gay. You can find show notes and transcripts for every episode at Astronomy Cast. You can email us at firstname.lastname@example.org, tweet us @AstronomyCast, like us on Facebook, and watch us on YouTube. We record our show live on YouTube every Friday at 3:00 p.m. Eastern, 12:00 p.m. Pacific, or 1900 UTC. Our intro music was provided by David Joseph Wesley. The outro music is by Travis Searle, and the show was edited by Susie Murph.
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Duration: 31 minutes