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The possibility and ethics of contaminating Mars. (Split from SpaceX.)


SunlitZelkova
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4 hours ago, SunlitZelkova said:

It should be noted there is no evidence the 300,000 number is actually meaningless. There may be a precise reason they chose that number, and the studies supporting it simply aren't available on the internet.

This is a rare conversation on this section of the forum where we actually lack the information to complete the discussion.

Agreed. But it just seems like too much of a coincidence that the number is exactly the number they assign as the possible number of spores on Viking.

I keep making fun of that number (strangely precise—just an order of magnitude I would expect, but not 3* an order of magnitude) because I want to know exactly what the concern is. Has anyone gotten any bacteria to grow in simulated martian conditions? Not "spores are still viable" but come back in X months and the spores dropped on soil simulant sitting in the simulated environment (with radiation) is growing? That seems like a test they could do tomorrow. Intentionally contaminate with a high density, too, to get the max chance of growth.

4 hours ago, SunlitZelkova said:

But again, "what if" 300,000 actually is helping to protect the Martian environment? Just because 300,000 might be incorrect does not justify completely abandoning planetary protection protocols.

If the number, bizarrely precise, and not a density of spores but a total number, regardless of vehicle size, is off by some orders of magnitude, then it's a garbage number, and nothing should be based on it at all. Maybe 300,000 is too LOW, maybe the cutoff is so low than we should not send anything larger than Spirit was. Who knows.

The treaty says reasonable care. Reasonable care is not "humans can't go unless you autoclave them," it's, "wipe everything down in the airlock deck with bleach solution." (or quats, whatever, maybe a few).

As I said, they could use suit ports, where the suits are sill inside SS. They could send sterilized rovers out from a SS. My concern about stuff on the outside of SS is ~0. If it doesn't fall off or get killed during months in space, why would it fall off once on Mars? A spore under a tile will still be there when it lands back on Earth.

 

4 hours ago, SunlitZelkova said:

However, that does not justify abandoning MSR with planetary protection standards or launching an unsterilized uncrewed Starship. It merely means planetary protection standards need review.

I have not suggested abandoning PP. I have suggested following it differently. The only treaty we have does not say "300,000 possible spores per vehicles" it says to take reasonable care.

 

Edited by tater
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The actual text:

Quote

States Parties to the Treaty shall pursue studies of outer space, including the Moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter and, where necessary, shall adopt appropriate measures for this purpose.

My bold.

Operative words being "avoid," and "shall adopt appropriate measures."

Seems open to literally anyone's interpretation as long as the measures were something a reasonable person could agree with.

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On 12/28/2021 at 9:43 PM, SunlitZelkova said:

But how long will it take to nail reentry? And then aerobraking? And then the task of landing on Mars, which they only have so many transfer windows to utilize?

Send multiple vehicles per transfer window, each trying a slightly different EDL pattern.

We don't have time for your tomfoolery.

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18 hours ago, tater said:

I keep making fun of that number (strangely precise—just an order of magnitude I would expect, but not 3* an order of magnitude) because I want to know exactly what the concern is. Has anyone gotten any bacteria to grow in simulated martian conditions? Not "spores are still viable" but come back in X months and the spores dropped on soil simulant sitting in the simulated environment (with radiation) is growing? That seems like a test they could do tomorrow. Intentionally contaminate with a high density, too, to get the max chance of growth.

In regards to this, part of the difficulty with relying on lab tests would be the lack of a true recreation of the Martian environment. How do we know what will happen if the spacecraft is buried over time? etc.

That's not to say a deeper look at what the requirements should not be undertaken, but it won't be as simple as one lab simulation.

18 hours ago, tater said:

The treaty says reasonable care. Reasonable care is not "humans can't go unless you autoclave them," it's, "wipe everything down in the airlock deck with bleach solution." (or quats, whatever, maybe a few).

As I said, they could use suit ports, where the suits are sill inside SS. They could send sterilized rovers out from a SS. My concern about stuff on the outside of SS is ~0.

My mention regarding how the 300,000 limit "might" be necessary or working was merely to demonstrate how one of the arguments you were using to criticize planetary protection did not have merit. Limits for robotic spacecraft could be changed as you mentioned in your reply, and limits for human missions will be different too.

MSR would, nonetheless, benefit from being performed prior to a human mission arriving.

I have not argued that humans can't go at all. I am of the opinion that MSR should be performed prior to a human or unsterilized mission.

18 hours ago, tater said:

If it doesn't fall off or get killed during months in space, why would it fall off once on Mars? A spore under a tile will still be there when it lands back on Earth.

Spores could get picked up on dust and fall to the ground later during the time on the surface. It gets everywhere and will certainly get under tiles.

18 hours ago, tater said:

The only treaty we have does not say "300,000 possible spores per vehicles" it says to take reasonable care.

Unsterilized Starship is not "reasonable care" though. It isn't unreasonable per say either, but it would not qualify as reasonable care.

1 hour ago, Nothalogh said:

Send multiple vehicles per transfer window, each trying a slightly different EDL pattern.

We don't have time for your tomfoolery.

This would help, but they can't make iterations easily. It could take the whole of the 2020s to get it down, and then, as I mentioned, it makes at least equal (if not more) sense from NASA's point of view to go with the NASA-ESA compartmentalized architecture for MSR.

Your tomfoolery comment appears to be misguided. The comment you quoted was in relation to why NASA doesn't use Starship for MSR, not a questioning or criticism of SpaceX's private development plans.

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4 hours ago, SunlitZelkova said:

Unsterilized Starship is not "reasonable care" though. It isn't unreasonable per say either, but it would not qualify as reasonable care.

If I were to buy a set of plates, and had to use them out of the box, but was told they were put in a room and brought to about -130C, then up to about 150C, and they sanitized them this way alternating those temps for a few months, would my plates be safe? Oh, and they also irradiated them with a couple hundred mGy. I think my plates are safe.

Reasonable care would be "BBQ rolling" the SS to expose it to sunlight (high temp). Isotropic GCRs will provide radiation sterilization. Yes, spores can live through that.

Bottom line is we have literally no idea how many spores it takes to contaminate Mars. If they can in fact grow there, Mars was "ruined" with the very first impact/landing. If they remain viable but dormant, it doesn't matter how many land there. Making a simulated environment is not that difficult, the civil engineers have done that already (I used to go to a space construction meeting here in town where all the guys working on lunar and martian concrete, etc, gave talks. They certainly have soil simulants (though they have more data for lunar, obviously). Put some in a pressure vessel, drop to martian atm pressure, with the right gas mixture, include a radiation source, and see what happens with spores. If they don't germinate, slide the parameters around within martian norms (temp, variable radiation, atm composition, etc). See how far out of martian norms before they germinate, then see if such areas might exist on Mars.

Seems completely reasonable to try this.

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Looks like astrobiologists have actually published designs for simulated environment chambers. Given the insanely high cost of actual Mars missions (even short of MSR), wonder if any have been built with the literal chump change required to do so. They could hand pick the spores they think are most likely to survive, and give them the best possible chance. If they get them to grow, then they sterilize, reset, and titrate the inoculum to the soil until they get below some % chance of successful spread (if most die in the soil). See what the actual requirement is—which might be impossible to attain.

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On 12/31/2021 at 8:15 AM, tater said:

See what the actual requirement is—which might be impossible to attain.

Until that though, we don't know. Unsterilized Starship currently would violate planetary protection standards agreed upon by various organizations and scientists.

SpaceX should conduct such an experiment themselves if they plan on racing ahead of the rest of the space exploration community, or donate money to assist another organization in doing so.

With the money they have and the power Elon exerts over the company, not doing so would be like a corporation who wants to build a coal fired power plant asking the poor people in the neighboring community to conduct an environmental assessment on their own. Contrary to the viewpoint of an armchair space agency manager, organizations are constrained by strict political and economic realities. They can't just do whatever they want, even if the money is there.

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Just now, SunlitZelkova said:

Until that though, we don't know. Unsterilized Starship currently would violate planetary protection standards agreed upon by various organizations and scientists.

Unless any of them think otherwise, and consider whatever they plan as "appropriate."

Nothing has been "sterilized." The standard seems literally pulled from someone's posterior—unless they have demonstrated Earth microbes reproduce in martial environment simulators, and somehow it's lower than 1:300k.

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4 minutes ago, tater said:

Unless any of them think otherwise, and consider whatever they plan as "appropriate."

True, but I have heard nothing so far. I wonder how much behind the scenes consultation there is between SpaceX and other entities.

4 minutes ago, tater said:

Nothing has been "sterilized."

Well, yes. Sterilized does not mean literally killing everything. It means doing the best you can.

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2 hours ago, SunlitZelkova said:

Well, yes. Sterilized does not mean literally killing everything. It means doing the best you can.

I'm not arguing against making a reasonable effort at all. My point is the 300k figure is pure nonsense. 300k per X m3, or per Y m2, sure, but the same number for Viking, Spirit, Curiosity, or Starship seems absurd, the standard does not scale at all. If the number is to somehow be "appropriate" and yet it's an absolute number, it's garbage, and really needs to be demonstrated.

Thought experiment:

Launch expendable Starship that will stage off the entire nose as a fairing. Fill it with as many landers as possible, call it 10 landers that are 10 tons (large MSR). Each has 300,000 spores per rules. They shotgun some region and rove around or whatever, then return samples. Congrats, they meet the rules, and yet that one launch just put 3M spores on Mars. Or shotgun small landers that are as small as possible to survive, and scan the surface. Starship can launch 200+ of them (that's between the mass of Viking and the Mars Polar Lander, totally doable). Each has 300k spores per the rules. Starship has now landed 60M spores on Mars.

Aren't arbitrary rules fun!

 

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4 hours ago, SunlitZelkova said:
4 hours ago, tater said:

Nothing has been "sterilized."

Well, yes. Sterilized does not mean literally killing everything. It means doing the best you can.

Quick aside, but "literally killing everything" is exactly what "sterilize" means. See Wikipedia.

 

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4 hours ago, Piscator said:

Quick aside, but "literally killing everything" is exactly what "sterilize" means. See Wikipedia.

 

Within a discussion about planetary protection is what I meant.

Within that context the word represents doing your best. There are a number of components that can't be truly sterilized, like some electronics. Instead of saying "most parts sterilized except for the components which were too sensitive", people just say sterilized.

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Normal air carries ~105 virion and bacteria particles per m3 (0.02μm-0.5μm for viruses, 0.5μm-5μm for bacteria). 90% are viruses. Viruses (are they a concern here?) cannot be stopped by normal filtration, even N95 (I think HEPA flters are the same) let 5% of 0.3μm particles through, and most viruses are smaller than that. Luckily for spores, it looks like most in the air are stopped by HEPA filtration. 95% of 0.3μm means that most all bacteria particles get stopped.

So clean rooms can work vs bacteria, but fairings? Who knows.

For metal surfaces, I would imagine that they could be sprayed with a disinfectant (dilute bleach is great), the question is does it remain effective on the surface with any efficacy vs spores (once dried). Maybe it makes the surface less likely to result in spores successfully germinating, probably doesn't destroy them.

3*105 spores implies that the spacecraft has to be exposed to normal air a shorter time period the larger the craft is. Which is of course impossible. If we know the rate at which spores settle/adhere to a surface in normal air, we can actually calculate an upper limit on spacecraft size.

EDIT: Scientifically, what are the contamination concerns? Actually seeding life seems the largest, since it's self-replicating by definition, and would then cover the whole place over time. Spores (that never germinate), or viral contamination is functionally just a possible sample contamination for soil samples taken to look for martian life. Oops, we got DNA/RNA mixed in the soil, and it shows up in test samples. In this case, it does seem like we should be able to tell.

Edited by tater
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