Human Missions versus Planetary Protection Limitations

Oldfart1939 · 2018-12-18 21:05:50

I bring up this topic as it was discussed--albeit in passing--at the Rocky Mountain Chapter of the Mars Society yesterday evening. The question seems to be having the ability to differentiate resident Martian organisms from Earth-borne contamination. My answer was blunt and unequivocally "Not a problem." It amounts to finding any organism which is based on DNA/RNA/proteins, versus anything else. Any other life form would be unquestionably unique w/r to it's biochemistry, but similar but Martian life forms would undoubtedly have some entirely different genomic character, immediately setting them apart from all know Earth genomes. My argument is the Planetary Protection advocates are refusing exploration and development of the planet until they are satisfied there are no native life forms extant, is utter hogwash. Any competent Biochemist would have no problem making this differentiation, given a suite of state of the art gene analyzers. The Planetary Protectionists seem to be within the Planetary Science group at NASA/JPL. Once we go to Mars, the "rice bowl of funding" they've enjoyed building probes and rovers goes almost entirely away.

Comments?

Void · 2018-12-18 21:18:59

I know you don't so much want me on your side, but I am on your side. I could do great blabbermouthing on the subject, but not tonight, not here. But it is an important matter.

How did these people become the Trustees of the solar system Trust fund, and try to lock us in a sanitorium? I think we should tell them to be more reasonable or we will bust out and they won't like it.

louis · 2018-12-19 05:10:40

Glad you brought this up OF, because I have mentioned this elsewhere that the planetary protection ideology is a real potential roadblock to settlement and exploration.

This panel has a lot of influence over NASA and the UN:

https://cosparhq.cnes.fr/scientific-structure/ppp

This is where self-interest and noble principle meet and shake hands!

No doubt people within NASA, ESA and the CNSA in China would be only too happy to slow things down...so they can catch up with Space X.

Maybe we'll see a different approach from NASA now - maybe they will be keen rather than reluctant to declare the probable presence of life on Mars...

The only possibility of contamination of Mars I see is if one of our extremophiles accidentally got dropped off on Mars. I doubt any other organism would last for long. What are the chances of an extremophile getting to Mars? As far as I know they don't exist in the human body, so there is no reason to think they would be more likely to accompany a human mission as opposed to a robot mission.

Space X do need to address the issue I think by eventually publishing a planetary protection plan and methodology - which would amount to doing the same stuff they do for Mars probes, in avoiding contamination as far as possible. Of course this is a return mission and you will have to have a plan to reduce the chances of contaminatino of Earth by Mars organisms, assuming they exist.

Oldfart1939 wrote:

I bring up this topic as it was discussed--albeit in passing--at the Rocky Mountain Chapter of the Mars Society yesterday evening. The question seems to be having the ability to differentiate resident Martian organisms from Earth-borne contamination. My answer was blunt and unequivocally "Not a problem." It amounts to finding any organism which is based on DNA/RNA/proteins, versus anything else. Any other life form would be unquestionably unique w/r to it's biochemistry, but similar but Martian life forms would undoubtedly have some entirely different genomic character, immediately setting them apart from all know Earth genomes. My argument is the Planetary Protection advocates are refusing exploration and development of the planet until they are satisfied there are no native life forms extant, is utter hogwash. Any competent Biochemist would have no problem making this differentiation, given a suite of state of the art gene analyzers. The Planetary Protectionists seem to be within the Planetary Science group at NASA/JPL. Once we go to Mars, the "rice bowl of funding" they've enjoyed building probes and rovers goes almost entirely away.
Comments?

Last edited by louis (2018-12-19 05:11:53)

GW Johnson · 2018-12-19 10:02:29

This is fairly simple in concept, with the devil in the details, of course.

1. Either there has been panspermia within the solar system or there has not. If there has been, then life on Mars and Earth share a common origin back at the microbe level. In that event, Mars life will share the same basic RNA/DNA, and could infect or eat us, and we it. If there was no panspermia, then the Mars life chemistry basis will be utterly different; it cannot infect or eat us, and we cannot infect or eat it.

2. Either way, current surface conditions on Mars are too harsh for any sort of organic chemistry life that we understand. Life there will be underground; something we only recently discovered and still don't understand very well here on Earth. It will be safe down there as long as we stay on the surface, and vice versa.

3. The danger only comes with terraforming Mars: once surface conditions are nonlethal, the underground microbes will recolonize the surface. That's when the panspermia question in my point 1 becomes important: once in contact, can the two forms of life interact? Good question, that one!

4. We did not find life on the moon during Apollo, or since. If it ever happened there at all, the remnants would be deep underground as microbes down in the rocks. Just something to think about as we put colonies on the moon. It may or may not be the lifeless rock that we currently think it to be.

The planetary protection crowd is right to worry about such things. But their goals are wrong. The real danger, if one exists, is to us.

GW

Last edited by GW Johnson (2018-12-19 10:04:24)

louis · 2018-12-19 14:59:16

1. I am not sure we can be certain a non RNA/DNA life form cannot infect us. We know that inanimate things like coal dust, flour and asbestos can harm us. Another carbon-based life form might play havoc with our bodily systems if breathed in or ingested.

2. Are you sure Earth-origin extremophiles can't survive on Mars?

https://en.wikipedia.org/wiki/Extremophile

3. If there are life forms on Mars, the dangers could become apparent before terraformation. Many people here argue we should place habs inside cave systems. Caves could well harbour life on Mars.

4. Quite possible.

GW Johnson wrote:

This is fairly simple in concept, with the devil in the details, of course.
1. Either there has been panspermia within the solar system or there has not. If there has been, then life on Mars and Earth share a common origin back at the microbe level. In that event, Mars life will share the same basic RNA/DNA, and could infect or eat us, and we it. If there was no panspermia, then the Mars life chemistry basis will be utterly different; it cannot infect or eat us, and we cannot infect or eat it.
2. Either way, current surface conditions on Mars are too harsh for any sort of organic chemistry life that we understand. Life there will be underground; something we only recently discovered and still don't understand very well here on Earth. It will be safe down there as long as we stay on the surface, and vice versa.
3. The danger only comes with terraforming Mars: once surface conditions are nonlethal, the underground microbes will recolonize the surface. That's when the panspermia question in my point 1 becomes important: once in contact, can the two forms of life interact? Good question, that one!
4. We did not find life on the moon during Apollo, or since. If it ever happened there at all, the remnants would be deep underground as microbes down in the rocks. Just something to think about as we put colonies on the moon. It may or may not be the lifeless rock that we currently think it to be.
The planetary protection crowd is right to worry about such things. But their goals are wrong. The real danger, if one exists, is to us.
GW

kbd512 · 2018-12-19 16:49:37

If human activities eventually disrupt some kind of microbial life on another planet, then that's evolution in action. If life on another planet eventually disrupts humanity, then that's also evolution in action. Either way, this has happened in the past and will continue to happen. The only difference is that humans have evolved to a point where some of us are naive enough to think we can prevent this from happening. All human history says that we can't. It's a risk, albeit a low probability risk, that doesn't have many good solutions at present.

If we're overly concerned with "alien bugs" that "could get us", then we should just stay home and hope that nothing from interplanetary space arrives with any visitors. If exploration is more important than worrying ourselves silly over things we can't prevent, then we should take reasonable actions to mitigate the risk and move on.

SpaceNut · 2018-12-19 17:59:40

The evolution of mars bacteria was slowed long ago and will develope very slowly as a result of energy available to transform into the higher forms that we now have along the evolutionary path for each type found.

louis · 2018-12-19 18:45:52

Yes, I agree. You need to view this as an existential matter, not like you are setting up a nature reserve. Our recent near miss with an inter-stellar object of unknown origin shows how vulnerable we are.

Maybe the lack of observable life in the cosmos is down to the fact that statistically it regularly gets wiped out by such objects or by organisms from other planets bringing plagues or other deadly events.

kbd512 wrote:

If human activities eventually disrupt some kind of microbial life on another planet, then that's evolution in action. If life on another planet eventually disrupts humanity, then that's also evolution in action. Either way, this has happened in the past and will continue to happen. The only difference is that humans have evolved to a point where some of us are naive enough to think we can prevent this from happening. All human history says that we can't. It's a risk, albeit a low probability risk, that doesn't have many good solutions at present.
If we're overly concerned with "alien bugs" that "could get us", then we should just stay home and hope that nothing from interplanetary space arrives with any visitors. If exploration is more important than worrying ourselves silly over things we can't prevent, then we should take reasonable actions to mitigate the risk and move on.

JoshNH4H · 2018-12-19 19:09:13

kbd512 wrote:

If life on another planet eventually disrupts humanity, then that's also evolution in action. Either way, this has happened in the past and will continue to happen.

This would be a fine thing to say if it were a fact from long ago history or something wholly beyond our control, but that's not what this situation is. What if, for example, we had reason to believe there was a small chance (0.1% maybe?) that microbes on Mars would infect the initial explorers and go dormant until it returned to Earth and wiped out a billion people. This has come up a lot in science fiction (I liked Aurora by Kim Stanley Robinson if you're looking for a recent example) but probably doesn't describe the real world.

Under that situation I think we would look prospectively at things and either not go or take precautions. "If humanity goes extinct, it goes extinct" seems like the wrong tack to take about an improbable but conceivable existential threat to our very existence.

I do think it's pretty unlikely that there are lifeforms on Mars that:

Exist
Are in a location where explorers and settlers could be exposed to them
Are infectious to humans or Earth-based lifeforms

I would be fairly confident based on our observations of the planet that most of the surface doesn't have life, even microbial life, but I can't be sure. Life can be a lot of things--basically any self-replicating physical pattern--and it's possible that there could be something on Mars we're just not looking for with the right sensors.

In the somewhat-unlikely case that there is life, I think it's unlikely that it's infectious. There is a spectrum of possibilities from the life being something so similar we could have found it on Earth (perhaps contamination from a Viking mission?) to something so different we're not even sure it's actually life (Rock-based life? Something else? In this thread we got creative). The more similar it is to us the more likely it can infect us or damage our equipment.

Above, I asked what we should do if the probability were 0.1% of there being a human-killer Mars plague. In reality I think the odds are way lower than that, maybe a million times lower. But possibly worth a quick test: With the early landing send down a fungus or something and expose it to some Martian dirt and air at STP.

The opposite question (danger to Martian life from Earth life) is worth looking at too. Martian life would be an incredibly rich area of study and it would be a crime against science to destroy it by carelessness. I don't think it's possible to destroy it without terraforming but if we find some we should definitely exercise extra care.

louis · 2018-12-19 19:52:31

One thing I think needs emphasising is that the risks of cross contamination exist with robot probes as much as human missions. NASA is planning sample return missions, I believe. These could just as easily return organisms as a human missions - perhaps they are more likely to do so, since humans can oversee sophisiticated "cleansing" processes.

SpaceNut · 2018-12-19 20:05:26

JoshNH4H what you speak of was the fear for the Apollo moon astronauts return and why we went in to quarantee for a period of time before being allowed out after splash down. Eventually the fear subsided and we moved on.

kbd512 · 2018-12-19 20:11:38

Josh,

Ah, yes, the illusion of "control". Apart from foregoing execution of this mission, which in no way guarantees that a human species extinction level event won't occur, we don't have the capability to control nature nor anything approaching such capability. Only people with more hubris than historical knowledge belief that humans control nature. We still don't fully understand ourselves, much less any other forms of life, so learning naturally involves making lots of mistakes. That's just part of the human condition at the present time. The only way we will gain greater insight into the nature of the universe is to explore new worlds.

My personal belief is that learning how to live and work on other worlds will ultimately incalculably increase the odds of the survival of the human species, even if the evolutionary process required for that to occur forces us to evolve over time. If we're never afforded the opportunity to make mistakes, then we're essentially never afforded the opportunity to learn. Apart from what works, I've learned far more from my mistakes or failures than I ever have from my successes.

I never said we shouldn't consider the possibilities, just that the possibilities shouldn't become an excuse not to go out and explore.

JoshNH4H · 2018-12-19 21:24:37

"That all things are possible is no excuse to speak foolishly" -John Maynard Keyes (possibly apocryphal)

I don't think you and I have particularly different conclusions on what ought to be done, but I really do take issue with the reasoning you used to get there.

Human extinction, whether by asteroid or mars-plague, is a tail risk, something improbable but very bad. Both are preventable to various degrees. The mode of argumentation "We have to go and nothing can stand in our way" doesn't hold much sway with me because frankly certain things ought to change our behavior if we believe them to be a danger.

Naturally we don't control anything, but our actions do have meaningful, material effects on the world we live in. Procedures to avoid contamination are quite well-developed and, depending on our assessment of the risk, could be worth implementing.

The need for pressurized habs and pressure suits gets us most of the way there anyway.

IanM · 2018-12-19 23:08:32

Of the prokaryotes and non-eukaryotes that are on Earth, less than 1% of bacterial species and no known archaebacterial species are pathogenic. Of those pathogens I would assume that the majority are no more virulent (severe) than the common cold or flu. If anything's a big threat for humanity on Earth it would be viruses, but on Mars viruses require the presence of other life forms to begin with, and likewise on earth most viruses are no more harmful than a common cold or flu.

Let's say that there is a 1 in 1,000,000 chance that life currently exists on Mars. Of that, let's say there's a half chance that it is in such a format that it possibly can infect colonists (so is not a form of life that is so alien as to preclude infection). Of those, let's go on a high end and say that one percent of the Earth-like life is pathogenic in humans. Of those, let's say that ten percent are virulent and severely deadly to the extent of Ebola, etc. That would (DISCLAIMER: All of these figures are arbitrary order of magnitude estimates and might not accurately reflect reality, but I believe that they are somewhat reasonable). All told, this gives a 5*10^-10 chance (or 5*10^-8% chance) that there exist pathogens on Mars that have the capacity to wipe out a human base, or 1 in 2 billion. By comparison, this says that the chance of getting struck by lightning is about 1 in 700,000 in a given year and 1 in 3,000 over the course of a lifetime.

That said, much like lightning it can be rather disastrous, and debating the relative worth of treatment and other care might also be affiliated with various costs.

JoshNH4H · 2018-12-20 00:11:22

I definitely have quibbles with your method and your figures, but ironically I estimated in my post that the odds are 1/1,000,000 of 0.1%, which is 1e-9 or 1e-7%, surprisingly close to your number. Happy coincidence maybe.

Anyway I think we all agree that the probability of back-contamination is extremely small but unlike many other questions or concerns has at least some grounding in science. European colonialism largely worked out okay for Europeans (at least as far as diseases go), but diseases were pretty much civilization-ending catastrophes for the indigenous people of the New World. If we imagine for a second that the disease vectors went the other way history would have been way different.

I'm not really concerned for the explorers and settlers. This is nowhere near the biggest risk to them (not even in the top 1,000 imo) and they'll know what they're getting into.

My expectation is that once the due diligence has been done we'll find that Mars has nothing alive that can hurt us, but it's an unknown with some small chance of ending us as a species and as such deserves extra care.

Hopefully our descendents on Mars will look back and laugh at us for testing the waters with a sacrificial lamb.

Terraformer · 2018-12-20 04:01:07

If we imagine for a second that the disease vectors went the other way history would have been way different.

Certainly, but I'm not sure that the old world would have been devastated. It's a bit difficult to sail back home when your crew have all died of disease, and having learned from the plague a century earlier, it's quite possible that any ships returning would have been placed under quarantine. Even if that didn't happen, we survived the loss of 1/3 of our population before.

The thing is, people will be on Mars for a fair bit of time before returning home. 2+ years between landing on Mars and landing on Terra. Enough time for any disease to show up, surely?

louis · 2018-12-20 08:51:53

I think it is still generally accepted that syphilis was brought from the New World to Europe and it did have a pretty devastating effect but not as bad as the other way round, admittedly.

https://www.scientificamerican.com/arti … -columbus/

JoshNH4H wrote:

I definitely have quibbles with your method and your figures, but ironically I estimated in my post that the odds are 1/1,000,000 of 0.1%, which is 1e-9 or 1e-7%, surprisingly close to your number. Happy coincidence maybe.
Anyway I think we all agree that the probability of back-contamination is extremely small but unlike many other questions or concerns has at least some grounding in science. European colonialism largely worked out okay for Europeans (at least as far as diseases go), but diseases were pretty much civilization-ending catastrophes for the indigenous people of the New World. If we imagine for a second that the disease vectors went the other way history would have been way different.
I'm not really concerned for the explorers and settlers. This is nowhere near the biggest risk to them (not even in the top 1,000 imo) and they'll know what they're getting into.
My expectation is that once the due diligence has been done we'll find that Mars has nothing alive that can hurt us, but it's an unknown with some small chance of ending us as a species and as such deserves extra care.
Hopefully our descendents on Mars will look back and laugh at us for testing the waters with a sacrificial lamb.

kbd512 · 2018-12-20 13:36:25

With modern medical training, tools, and procedures, the US was never able to prevent the spread of Ebola in Africa. The Central American illegal immigrants that came from Central and South America brought Zika with them, unbeknownst to the CDC at that time. We found out later and dealt with the problem.

We now have the beginnings of vaccines for Ebola and Zika. The VSV-EBOV vaccination has been empirically proven to be 95% to 100% effective through unintentional exposures to Ebola. The Zika vaccine is now in clinical trials and our scientists are pretty sure we have that nasty little bugger licked as well. There is also a new HIV vaccine now in clinical trials and as difficult as that little nasty has been to kill, we're finally cooking with a blow torch.

The US government has known how to prevent mosquito-borne illnesses since the 1950's. It's called DDT. It worked so well that a well-intentioned environmentalist woman convinced key US lawmakers to draft legislation to stop using DDT. It's well known these days that her entire line of argumentation was based on scientific falsehood and emotional appeals, as is so frequently the case with hopefully well-intentioned but nonetheless ignorant and/or arrogant people who believe they know far more than they actually do. A lot of people sure as hell died from mosquito-borne illnesses after we stopped using DDT.

Does that sound familiar to those of us fighting this global climate change malfeasance? That could never possibly happen with "climate change" because our climate science religious zealots have precisely the right mix of ignorance, arrogance, and hubris to believe that they know far more than they actually do. Anyway, rational people shouldn't allow their imaginations run wild and instead stick with what we can empirically prove beyond a reasonable doubt. In the case of all known and unknown human pathogens, humans still came out on top since humans have existed. If we hadn't, then I wouldn't be writing this. Even with our rudimentary knowledge of how to deal with pathogens, historically it's been proven to be remarkably hard to kill us all. Unlike all other forms of life on this planet, we're capable of higher levels of abstract thought processes and we're very curious as a species, even if that's proven detrimental to some of us at certain times.

As our DNA encoding technology races ahead, in the next decade or so it will quickly become exceptionally difficult for a virus or bacteria to cause mass death amongst human populations, although our food stocks (plants and animals) could still be rapidly decimated by a virus or bacteria that infects them before we understand enough about the plant or animal in question to stop an infection from spreading.

I would bet on a virus or bacteria from Mars affecting other animals or plants on Earth before something affecting humans since whatever could possibly be alive on Mars is either already on Earth or was never native to Earth to begin with and the available attack surface for a Mars native pathogen is so much greater for all other species on our planet. If the surface environment of Mars is inhospitable to Martian life forms, then we already know how to kill whatever could be alive on Mars, buried somewhere deep within a well of liquid subsurface water.

Be afraid of things that will kill astronauts long before any virus ever could, like running out of electrical power, life support systems failure, reentry aerodynamic and thermodynamic forces, material failures in anything from pressure vessels to rocket turbo pump assemblies capable of causing rapid unscheduled deconstruction, etc. Events such as those have a high degree of probability of fatal consequence.

Here on Earth, be afraid of idiots with anything from ideas not based upon rock hard evidence to nuclear weapons. The term "idiot" would apply equally to any politician who ever lived and scientists who aren't clairvoyant also fit that description, no matter how intelligent. Foolishness, it would seem, is not limited to a specific level of education or chosen profession.

When I say that humanity will survive, I don't actually know anything. That was a roundabout way of calling myself another one of those arrogant and ignorant idiots making claims or prognostications about the future that I couldn't possibly actually know with any degree of certitude. The difference is that I have all available historical evidence backing my assertion, without qualification of any kind, not an estimation / conjecture / wild guess with a specific confidence level attached to it.

SpaceNut · 2018-12-20 16:55:56

Lacking a land bridge from Africa to the US was the only reason it did not spread ebola from africa. Thou it may be close with air flight if it were not for the checks which are done. Insects fly so in time it still would have got here.
DDT was an environmental issue as it was killing birds and other such egg laying creatures by thining of there shells.
Climate change is effecting habitats for all creatures and that is stimulating those that normally would be slow to change to accelerate its change.

Void · 2018-12-22 15:19:09

I will try to go more on topic now as this is quiet, I am sore from 6 workouts this week and only want to sit in a chair.

Louis in his post #2 said:
Quote:

No doubt people within NASA, ESA and the CNSA in China would be only too happy to slow things down...so they can catch up with Space X.
Maybe we'll see a different approach from NASA now - maybe they will be keen rather than reluctant to declare the probable presence of life on Mars...

And so, that is where some of the demons are from. But there seem to be some angels. The intention to do right is worth consideration. Not allowing the anti-Mars, anti-our kind demons to exploit good intentions is also worth consideration. The road to hell being said to be paved with good intentions.

…..

My opinion follows.

In a sense SpaceX BFR/BFS....Super Heavy Launcher/Starship, can force the issue, if they make it capable of doing what they say it can do.

Then the "Heavenly and Satanic" powers may or may not be able to stop that process. If they don't I guess it is out of my hands. SpaceX makes the effort and does or does not succeed with our without bitter losses.

If they, the opponents, can produce a political impediment of significance, then it is time to consider a counter move. (In my opinion).

It is sort of a "You will like me a lot better if you put up or shut up!" thing.

That is, if they are so interested in the Angelic nature of the quest, then they will provide SpaceX with the money and interest to do things different, more protective. If it is Demons, though I will think it quite likely that they will not respond properly, unless they intend to get intimate so they can do a evil betrayal, say sabotage to the effort.

……

And so, should they be confronted with that, what could be offered is a more cautious but perhaps in the long term beneficial plan.

I believe that BFR/BFS.....SuperHeavyLifter/Starship has vastly more capabilities than is advertised. Vastly, Vastly, Vastly!

A lot of this I have previously mentioned elsewhere.

Piggybacking. There is no reason that a "Starship" could not get a "Boost" from another "Starship" prior to leaving the Earth/Moon subsystem. Why? Well, to have more propellants upon reaching Mars.

There is no reason to not consider additional external tanks for the BFS/Starship to come along in transit. SpaceX likes to recycle hardware but for practical/money reasons does not always do so. Such an external carry along fuel depot could be expended beyond the Earth/Moon realm and cast away or taken along. Such a device should be possible to be lofted to LEO by a BFR/Starship of a cargo type with a alligator type nose prior to the mission.

And then there is little reason to not consider "Ballistic Capture" of a BFS/Starship to Martian orbital space, without a landing. This also would save on propellants. I would expect for now that this would be a uncrewed type mission.

……

Ballistic Capture. Yee.....Hay! Here we try again.

https://www.scientificamerican.com/arti … the-cheap/
Quote:

A New Way to Reach Mars Safely, Anytime and on the Cheap

That's what they said.

I feel that it is very nicely described. For the mission of "Put up or shut up!" my desire would be to avoid aeroburn to Mars. Just get into orbit, go check some stuff out, and go home if you can.

Alright this would be a top down method.

Toes in the water before you jump in.

So check out Demos and Phobos with a very beefed up radar system. Do similar for Mars as well, particularly the areas of interest.

Consider samples from Phobos and Demos. How about sample return from Mars itself? If they are in part composed of Mars rocks ejected to orbit by impacts of Mars, there may be samples to further describe the potential or even the prior existence of life on Mars.
Very important!

Well. Put up or shut up means they pay some of it maybe a lot of it.

So, many of you here may not like this plan, I consider it just payment to those who have wasted our lives for so long, slowing down humanities reach into space.

Indeed they should pay if they want to have sway over these matters.

They should not be allowed to use demonic domination and demands of subservience and tribute.

Done.

Last edited by Void (2018-12-22 15:59:17)

JoshNH4H · 2018-12-27 11:02:27

Sorry for my absence over the holidays, but I've split off the discussion of climate change and moved it to this thread, "The Science of Climate Change", in the "Science, Technology, and Astronomy" subforum.

Mars_B4_Moon · 2023-11-24 06:39:02

Magazine Says That We’re Occupying Space As Colonizers

https://aerospaceamerica.aiaa.org/depar … lonialism/

American Institute of Aeronautics publication, AIAA's magazine reaches nearly 25,000 aerospace professionals

SpaceNut · 2023-11-24 09:28:31

Sure, we can so fear but the reality is man takes very little bacteria and other virus content with them to space currently. Al fear of reactivation of a dormant one from where we land can be proven out even here on earth as the ice sheets melt.

New Mars Forums

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#1 2018-12-18 21:05:50

Human Missions versus Planetary Protection Limitations

#2 2018-12-18 21:18:59

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#3 2018-12-19 05:10:40

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#23 2023-11-24 09:28:31

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