How microbes survive clean rooms and contaminate spacecraft(phys.org)
phys.org
How microbes survive clean rooms and contaminate spacecraft
https://phys.org/news/2018-06-team-microbes-survive-rooms-contaminate.html
69 comments
Wow that's very interesting. What do they do with 1) and 2)? Just accept it or kill it another way?
Why is 3) so resistant against radiation? Does it repair DNA damage faster than it occurs?
Do you mind me asking if you're working in industry or are in academia/research? :)
Why is 3) so resistant against radiation? Does it repair DNA damage faster than it occurs?
Do you mind me asking if you're working in industry or are in academia/research? :)
Kill it some other way, and frequently test things that should be 'sterile'.
I don't actually study (3) particularly, nor am I a biologist. As far as I understand, the "how" question is pretty well studied, and is because it's pretty aggressive with DNA repair, and has lots of various tricks to facilitate that and minimize damage from occurring in the first place. The question of "why" is (in my mind) more interesting, and less understood - it may be due to evolving to deal with prolonged dehydration, which is a much more useful ability for life on earth. IDK.
R&D at a startup.
I don't actually study (3) particularly, nor am I a biologist. As far as I understand, the "how" question is pretty well studied, and is because it's pretty aggressive with DNA repair, and has lots of various tricks to facilitate that and minimize damage from occurring in the first place. The question of "why" is (in my mind) more interesting, and less understood - it may be due to evolving to deal with prolonged dehydration, which is a much more useful ability for life on earth. IDK.
R&D at a startup.
Thanks for the reply – I actually thought there was some stuff no bacteria could live in and that probably exists, but then you also get problems with the things you are trying to desinfect.
Excuse my ignorance. Are there any bacteria that have some type of resistance to bleach? This scares me.
Yes, and No.
No in the sense that phospholipids and proteins and hydrocarbons in general are delicious to bleach. Exactly like asking if there are bacteria that can survive being incinerated in a fire, at a chemical level the molecules in their cell walls get broken up. There is no simple hack a unicellular organism can apply to survive strong enough bleach or fire, at a very low chemical level its being destroyed. Would silicon based life tolerate bleach? I'd have to think about that a bit.
Yes in the sense that if you play games with very low concentrations you will slowly preferentially breed stronger cells, much as you could breed fire resistant wood, but all wood vaporizes in a strong incinerator. Obviously Homeopathy is not a thing scientifically, a small amount of bleach dumped in a pond won't kill everything in the pond but it will kill the weakest whatever in the lake, leading to increased breeding of stuff resistant to extremely low bleach concentrations. However even in theory I don't think anything could live in a bottle of normal strength bleach.
There are also categorical issues, a very thick layer of algae when splashed with bleach will have the outer layer die and eventually melt off, but the layer underneath will simply regrow. Does that mean algae is resistant in the overall system sense even though it dies really easily? People are usually only interested in systemic success, so sure, its very easy for bacteria to survive bleach based cleaning. A nice thin layer of bulk grease or oil that lasts long enough to protect at least some bacteria underneath that isn't completely removed during the cleaning, there you go, bacteria that survived bleach cleaning, although no bacteria individually can survive full strength bleach, a sufficiently thick layer of grease protecting some bacteria can survive a sufficiently short enough bleach cleaning process.
No in the sense that phospholipids and proteins and hydrocarbons in general are delicious to bleach. Exactly like asking if there are bacteria that can survive being incinerated in a fire, at a chemical level the molecules in their cell walls get broken up. There is no simple hack a unicellular organism can apply to survive strong enough bleach or fire, at a very low chemical level its being destroyed. Would silicon based life tolerate bleach? I'd have to think about that a bit.
Yes in the sense that if you play games with very low concentrations you will slowly preferentially breed stronger cells, much as you could breed fire resistant wood, but all wood vaporizes in a strong incinerator. Obviously Homeopathy is not a thing scientifically, a small amount of bleach dumped in a pond won't kill everything in the pond but it will kill the weakest whatever in the lake, leading to increased breeding of stuff resistant to extremely low bleach concentrations. However even in theory I don't think anything could live in a bottle of normal strength bleach.
There are also categorical issues, a very thick layer of algae when splashed with bleach will have the outer layer die and eventually melt off, but the layer underneath will simply regrow. Does that mean algae is resistant in the overall system sense even though it dies really easily? People are usually only interested in systemic success, so sure, its very easy for bacteria to survive bleach based cleaning. A nice thin layer of bulk grease or oil that lasts long enough to protect at least some bacteria underneath that isn't completely removed during the cleaning, there you go, bacteria that survived bleach cleaning, although no bacteria individually can survive full strength bleach, a sufficiently thick layer of grease protecting some bacteria can survive a sufficiently short enough bleach cleaning process.
Intriguing & fascinated. The very idea of bacteria producing stronger cells in response to chemical agents in relatively short periods of time is an idea I can ponder for hours. Thank you.
Has there been a study addressing whether these clean rooms are completely counterproductive to their stated goal?
It seems intuitive to me that if you're maintaining such a clean room the only bacteria that are going to live there are ones hardy enough to survive in those extreme conditions, you're just going to be running an accidental breeding program for bacteria likely to survive on a spacecraft.
As opposed to just assembling all this stuff in a room open to the elements. It would then be completely inundated with bacteria, but none of them would have any selective advantage in being hardy. You could even feed them on purpose by spraying food for them everywhere.
Then when you launch the spacecraft those fat comfortable bacteria would all instantly die because vacuum isn't an environment that's anything like what they've had to deal with, unlike the hardy ones in the clean room, and the few survivors would have no time to develop hardiness. They'd all die within hours from launch.
It seems intuitive to me that if you're maintaining such a clean room the only bacteria that are going to live there are ones hardy enough to survive in those extreme conditions, you're just going to be running an accidental breeding program for bacteria likely to survive on a spacecraft.
As opposed to just assembling all this stuff in a room open to the elements. It would then be completely inundated with bacteria, but none of them would have any selective advantage in being hardy. You could even feed them on purpose by spraying food for them everywhere.
Then when you launch the spacecraft those fat comfortable bacteria would all instantly die because vacuum isn't an environment that's anything like what they've had to deal with, unlike the hardy ones in the clean room, and the few survivors would have no time to develop hardiness. They'd all die within hours from launch.
Unfortunately that is not the way the microbes of this world (and now other worlds) work. The form that is really tough is the bacterial spore (spores are one of the lifecycle stages of some bacteria). These spores can survive in a complete vaccuum for years. The more bacteria you introduce into a system the more spores you will end up with contaminating everything.
I personally doubt that this contamination is much of a problem. The planets of the solar system have been dusted in earth rocks containing bacterial spores thrown up by large asteroid strikes for billions of years.
I personally doubt that this contamination is much of a problem. The planets of the solar system have been dusted in earth rocks containing bacterial spores thrown up by large asteroid strikes for billions of years.
It's certainly a problem when the spacecraft's job is to detect life on other planets. If the spacecraft is contaminated with Earth microbes then it will get a false positive which is a huge problem.
The reason I don't think it is a problem is that "Earth" microbes will have got to the planet long before the spacecraft.
Planes are huge and finding remnants of one such strike would still be significant.
However tiny the spacecraft's contamination is going to be right next to the sensors making false positives easy. Longer term they will likely all die out, but they could still contaminate samples taken over huge areas for the next decade.
However tiny the spacecraft's contamination is going to be right next to the sensors making false positives easy. Longer term they will likely all die out, but they could still contaminate samples taken over huge areas for the next decade.
Uh, it kind of is a problem if that statement is the hypothesis the probe is designed to test.
Even if the probe was not contaminated the planets already are. We are likely to find that there is life on Mars (underground) and it looks just like life on Earth.
One interesting theory is that life originated outside the Earth (say on Mars) and was transported to Earth at a later time. This theory would explain why LUCA [0] is so complex and why life appears almost as soon the Earth had liquid water [1].
0. https://en.wikipedia.org/wiki/Last_universal_common_ancestor
1. https://en.wikipedia.org/wiki/Earliest_known_life_forms
One interesting theory is that life originated outside the Earth (say on Mars) and was transported to Earth at a later time. This theory would explain why LUCA [0] is so complex and why life appears almost as soon the Earth had liquid water [1].
0. https://en.wikipedia.org/wiki/Last_universal_common_ancestor
1. https://en.wikipedia.org/wiki/Earliest_known_life_forms
Yes, but you can't test that hypothesis if the probe is contaminated. Science isn't about assuming likely things to be true.
>This theory would explain why LUCA [0] is so complex and why life appears almost as soon the Earth had liquid water [1].
from the wikipedia article:
>LUCA should not be assumed to be the first living organism on Earth
from the wikipedia article:
>LUCA should not be assumed to be the first living organism on Earth
On the other hand it should not be assume that it is not. The complexity of LUCA is a problem since LUCA is not much less complex than a modern bacteria which is very, very complex.
There’s zero chance any scientist will mistake the DNA of an existing Earth microbe with alien life.
I don't think any search for life on other planets begins with looking for and sequencing DNA so the time between getting a false positive and disconfirming it could be a decade or more and be extremely costly to send unneeded equipment to Mars or Europa or wherever.
That's a very good point, I didn't think of this lag. Now considering we just did this thought experiment, maybe it wouldn't be a bad idea for any mission to Mars in search of life to have some cheap way of identifying Earth-based microbes, by, for example, coupling a cheap microscope with some machine learning. It wouldn't replace DNA sequencing, but it could be 95% there. Oh, and by the way, assuming we do find some extraterrestrial life form, wouldn't we want to find the way it encodes information as soon as possible, rather than wait for a decade or more for a follow up mission?
> identifying Earth-based microbes
An extremely expensive although effective approach would be to "seed" the spacecraft with isotopically enriched and documented solvents and food sources such that all the oxygen or carbon or both on the spacecraft, if any contamination DOES exist, would be a peculiar and documented isotope ratio that is different than Mars ratios.
I think we know the natural ratios for Mars in bulk material, so anything immediately found to be growing that matched the documented "salted" isotope ratios obviously was a spacecraft contaminant whereas anything mars ratio was local. Of course bacteria can reproduce fast, so Earth bacteria eating Mars material would rapidly revert to Mars isotope ratios. Still for the first hour on the ground this would likely be usable for life detection experiments. Although it would probably be unimaginably expensive.
An extremely expensive although effective approach would be to "seed" the spacecraft with isotopically enriched and documented solvents and food sources such that all the oxygen or carbon or both on the spacecraft, if any contamination DOES exist, would be a peculiar and documented isotope ratio that is different than Mars ratios.
I think we know the natural ratios for Mars in bulk material, so anything immediately found to be growing that matched the documented "salted" isotope ratios obviously was a spacecraft contaminant whereas anything mars ratio was local. Of course bacteria can reproduce fast, so Earth bacteria eating Mars material would rapidly revert to Mars isotope ratios. Still for the first hour on the ground this would likely be usable for life detection experiments. Although it would probably be unimaginably expensive.
Are there machines that can sift through a sample of dirt, detect cells and isolate them for library prep and sequencing? Or are you thinking of human missions to Mars?
It seems likely that there will be such machines within a few years. There is nothing in this procedure which can't be automated using existing technology.
There's an open hypothesis that life may have evolved elsewhere in the universe and then brought to Earth by some means. DNA would probably have diverged by now, but who knows?
As I understand it DNA and RNA store their information in the form of certain amino acids. If other life uses amino acids in a similar fashion they may not use the same ones that life on Earth uses. Life here uses I believe 20 different amino acids and there are several hundred known.
So there's potential there I would imagine in regards to testing that hypothesis. However what mainly bothers me with it is that it doesn't explain the origin of life and why Earth couldn't have original life begin on it.
Unless we can rule out that early Earth conditions would have been too inhospitable for life to start but was sufficient to sustain it I see no reason to think an extraterrestrial origin to Earth life is more likely.
So there's potential there I would imagine in regards to testing that hypothesis. However what mainly bothers me with it is that it doesn't explain the origin of life and why Earth couldn't have original life begin on it.
Unless we can rule out that early Earth conditions would have been too inhospitable for life to start but was sufficient to sustain it I see no reason to think an extraterrestrial origin to Earth life is more likely.
> As I understand it DNA and RNA store their information in the form of certain amino acids.
Actually, information is stored as RNA, with DNA as long-term storage (mnemonic: RAM nucleic acid vs disk nucleic acid) and then amino acids are assembled into proteins (hardware) based on that information. Proteins only function as information storage in pathological cases like prions.
But yes, if 'alien' life used the same 20 amino acids, and especially if it has the same mapping from 64 nucleic acid triplets to 20 amino acids, then that's confirmation that it's actually just a earth microbe that escaped or was left behind.
Actually, information is stored as RNA, with DNA as long-term storage (mnemonic: RAM nucleic acid vs disk nucleic acid) and then amino acids are assembled into proteins (hardware) based on that information. Proteins only function as information storage in pathological cases like prions.
But yes, if 'alien' life used the same 20 amino acids, and especially if it has the same mapping from 64 nucleic acid triplets to 20 amino acids, then that's confirmation that it's actually just a earth microbe that escaped or was left behind.
Agreed that the extraterrestrial origin hypothesis doesn't actually explain anything. It just merely adds a factor to the Drake equation of how likely it is for life to get started.
You can identify statistical differences after some generations of bacterial life in the lab, as far as I recall, i.e. a very short period of time at human-scale.
Therefore, yes, life would have diverged sufficiently that scientists should be able to tell the difference.
Therefore, yes, life would have diverged sufficiently that scientists should be able to tell the difference.
> There's zero chance
Why do you assume so? It's possible a sattelite in the Solar System was contaminated by Earthling bacterias via asteroids and somehow miracalously adapted that environment. If this is true, scientists would find a group of bacteria branched off of bacteria here on Earth a billion year ago or so.
Why do you assume so? It's possible a sattelite in the Solar System was contaminated by Earthling bacterias via asteroids and somehow miracalously adapted that environment. If this is true, scientists would find a group of bacteria branched off of bacteria here on Earth a billion year ago or so.
Not to mention asteroids of interstellar origin.
>Has there been a study addressing whether these clean rooms are completely counterproductive to their stated goal?
What is a cleanroom's stated goal? Implying the cleanroom's only purpose is for reducing the risk of forward contamination.
Spacecraft will be manufactured in a cleanroom regardless of effectiveness at stopping microbial forward contamination. Foreign Object Debris, payload and bus contamination during manufacture are the primary concerns. For example, dust or condensate on an optical payload would ruin a Discovery class mission.
The stated goal of a clean room is for quality control, reducing microorganism forward contamination is a secondary.
What is a cleanroom's stated goal? Implying the cleanroom's only purpose is for reducing the risk of forward contamination.
Spacecraft will be manufactured in a cleanroom regardless of effectiveness at stopping microbial forward contamination. Foreign Object Debris, payload and bus contamination during manufacture are the primary concerns. For example, dust or condensate on an optical payload would ruin a Discovery class mission.
The stated goal of a clean room is for quality control, reducing microorganism forward contamination is a secondary.
I don’t know what Kleenol 30 is, but I would have thought it obvious that ethanol and isopropyl alcohol are insufficient to sterilise.
My immediate thought with regard to cleanliness is always moulds.
It’s not clean until it’s been soaked in sodium hypochlorite and sodium hydroxide, UV sterilised, gamma irradiated, then parked in a decaying orbit above the sun.
My immediate thought with regard to cleanliness is always moulds.
It’s not clean until it’s been soaked in sodium hypochlorite and sodium hydroxide, UV sterilised, gamma irradiated, then parked in a decaying orbit above the sun.
They didn’t test whether Kleenol was sufficient to sterilize. They were showing that without access to any other nutrient/carbon source, the bacteria were able to degrade and metabolize a variety of cleaning agents, Kleenol among those tested.
That is, they weren’t saying “hey, this bullet is ineffective against that tank.” They were saying, “deprived of oil, that tank started eating bullets.”
That is, they weren’t saying “hey, this bullet is ineffective against that tank.” They were saying, “deprived of oil, that tank started eating bullets.”
Kleenol 30 is sold as a degreaser.
http://www.missionlabs.net/cleaners.html
> A highly concentrated, industrial strength heavy-duty cleaner/degreaser. Can be used for light duty washing to heavy-duty steam cleaning.
Kleenol 30 is a mix of
> BENZENESULFONIC ACID, DODECYL‐, SODIUM SALT; (DODECYL BENZENE SULFONIC ACID) (CERCLA).
> Fraction by Wt: 1%
> SILICIC ACID (H2SIO3), DISODIUM SALT; (SILICILIC ACID DISODIUM SALT)
> Fraction by Wt: 1‐4%
> ETHANOL, 2‐BUTOXY‐; (ETHYLENE GLYCOL MONOBUTYL ETHER)
> Fraction by Wt: 12.5%
> GLYCOLS, POLYETHYLENE, MONO(NONYLPHENYL) ETHER; (NONYL PHENOL ETHOXYLATE).
> Fraction by Wt: 1-5%
> A highly concentrated, industrial strength heavy-duty cleaner/degreaser. Can be used for light duty washing to heavy-duty steam cleaning.
Kleenol 30 is a mix of
> BENZENESULFONIC ACID, DODECYL‐, SODIUM SALT; (DODECYL BENZENE SULFONIC ACID) (CERCLA).
> Fraction by Wt: 1%
> SILICIC ACID (H2SIO3), DISODIUM SALT; (SILICILIC ACID DISODIUM SALT)
> Fraction by Wt: 1‐4%
> ETHANOL, 2‐BUTOXY‐; (ETHYLENE GLYCOL MONOBUTYL ETHER)
> Fraction by Wt: 12.5%
> GLYCOLS, POLYETHYLENE, MONO(NONYLPHENYL) ETHER; (NONYL PHENOL ETHOXYLATE).
> Fraction by Wt: 1-5%
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"It’s not clean until it’s been soaked in sodium hypochlorite and sodium hydroxide, UV sterilised, gamma irradiated, then parked in a decaying orbit above the sun."
By that time, you've also 'sterilised' most electronics...
By that time, you've also 'sterilised' most electronics...
The idea being that passing through the two million or so degree corona would neutralise Artificial Intelligence too.
They don't just use chemicals, quite a lot of components are heated to a minimum of 110 centigrade as well, see https://marsmobile.jpl.nasa.gov/msl/mission/technology/insit...
I don’t know what Kleenol 30 is, but I would have thought it obvious that ethanol and isopropyl alcohol are insufficient to sterilise.
Does the article mention they were used to sterilise or that there weren't other products?
Does the article mention they were used to sterilise or that there weren't other products?
"I would have thought it obvious that ethanol and isopropyl alcohol are insufficient to sterilise"
Especially since no hospital would rely on just ethanol and isopropyl. You'd think they'd at least try to live up to the standards of a hospital.
Especially since no hospital would rely on just ethanol and isopropyl. You'd think they'd at least try to live up to the standards of a hospital.
Consider also that hospitals are a good place to hang out if you want to get a cleaning product and antibiotic resistant bacterial infection.
This is why I covered my existing procedure "wounds" with loads of vaseline and securely bandaged them, before I went in for another, longer, procedure. The nurses and doctors were completely understanding and made sure to tell anyone involved, which was good to hear.
Of course, I'm not sure how effective that sort of prep would be, but I hope I reduced my risk, at least.
Of course, I'm not sure how effective that sort of prep would be, but I hope I reduced my risk, at least.
That’s probably a really good idea, smart thinking.
It’s a wonder hospitals don’t require existing wounds to be dressed in touch a way prior to admission.
It’s a wonder hospitals don’t require existing wounds to be dressed in touch a way prior to admission.
It's a different issue. You can't autoclave your spaceship for example. Or use the same substances they use, though you might be able to use other ones
I've been using Hibiclens (Chlorhexidine) lately after a couple of different medical procedures.
Makes me wonder why Hibiclens is OK for skin use but not for use on inorganic surfaces like metal or plastic?
Makes me wonder why Hibiclens is OK for skin use but not for use on inorganic surfaces like metal or plastic?
Apollo 12 landed right next to the Surveyor 3 lander, and the astronauts removed a few pieces from it and returned with them. When NASA disassembled the video camera later they found microorganisms still alive on the device.
This article asserts that this was the result of a clean room failure after the parts were returned to Earth: https://www.space.com/11536-moon-microbe-mystery-solved-apol....
This is not as exciting as the notion that some bacteria might have survived for years inside the lander on the Lunar surface, but it still illustrates the risks of failing to maintain a proper clean room environment.
This article asserts that this was the result of a clean room failure after the parts were returned to Earth: https://www.space.com/11536-moon-microbe-mystery-solved-apol....
This is not as exciting as the notion that some bacteria might have survived for years inside the lander on the Lunar surface, but it still illustrates the risks of failing to maintain a proper clean room environment.
Well I guess that answers the question if there is life on mars.
What are you trying to say?
I suspect his point is that due to sending rovers to mars, there likely is life there, now at least.
Exactly. Actually it is near certain that there is life on Mars now since we know the spacecraft sent were not sterile.
Why are you so sure? Are you an expert in extremophile metabolism? I find it very unlikely that an Earthling could survive in Mars, microorganism or not, it would be a chain of miraculous events for an Earthling metabolism to find enough processible energy in Mars.
But it's a godawful small affair
Tl;Dr: consuming ethanol from the cleaning products and surviving the corresponding oxidative stress
Is it possible that in millions of years the microorganisms we have inadvertently sent to Mars will evolve? Even in the short term, that seems like an interesting experiment in itself.
The politics of this discussion is amazing in the sense that we can have a non-political discussion of if bacteria born on earth and growing on mars are earth life or mars life or is it morally right or wrong to transport life or "contaminate" existing cultures. However the analogy is nearly perfect if we're debating if someone born in Syria and living in England is a Syrian-lifeform or a English-lifeform and is it morally or ethically OK to "contaminate" cultures. Its interesting in that without political agitation this relatively calm and straightforward discussion is what immigration debate would look like, but we're not allowed not to be politically agitated to a certain outcome, for some reason. Or, with a hundred years of political "progress" and parallel technological advance, immigration to Mars will have a political dimension such that sterilizing in satellite-grade clean rooms and talking about contamination fears will sound like pro-nazi death camp talk to future politically active young multicultural people living on Mars and the legacy Earth.
Rather than try to remove all contaminants, is it possible to mark them with an indicator of their origin?
So we need bacterivirous nanobots ...
(We'll probably make self-replicating ones that destroy all life.)
(We'll probably make self-replicating ones that destroy all life.)
A bacteriophage? https://en.wikipedia.org/wiki/Bacteriophage
Nature already invented those and they kill off 30% of life in the oceans every day (of course, by the end of the day the bacteria on the other end of this battle have replicated again).
Bacteriophages are what you want, you just need to find the right strain.
Bacteriophages are what you want, you just need to find the right strain.
A short animated introduction to Bacteriophage by Kurzgesagt: https://www.youtube.com/watch?v=YI3tsmFsrOg
Bacteriophage means "bacteria eater" but my understanding was from a brief review that they don't eat them so much as use them as host?
Roundworms, acari, springtails, and such eat bacteria though; they're apparently known collectively as detritivores.
Roundworms, acari, springtails, and such eat bacteria though; they're apparently known collectively as detritivores.
They don't really eat them, correct. Instead they force the bacteria to produce new phages until it explodes under internal pressure and dies.
Plus, phages are viruses, unlike roundworms and the like, they can survive centuries without food.
They also, as mentioned, account for 30% of death in marine life every day, biggest killer organism on this planet.
There is phage-therapy too, an alternative to anti-biotics, where you are given a dosage of phages in an infected area. Due to their nature they only attack specific strains of bacteria and can easily eradicate the entire population within a few hours.
Plus, phages are viruses, unlike roundworms and the like, they can survive centuries without food.
They also, as mentioned, account for 30% of death in marine life every day, biggest killer organism on this planet.
There is phage-therapy too, an alternative to anti-biotics, where you are given a dosage of phages in an infected area. Due to their nature they only attack specific strains of bacteria and can easily eradicate the entire population within a few hours.
I assume they mean sterile when they say clean. Why do we still insist only on sterile environments? Shouldn't we focus on creating small eco systems that are suitable for humans, where probably lots of different microbes that are beneficial to us are included..
The point is, we don't want to start ecosystems on the planets and moons of the solar system until we're good and ready - and have checked that nothing was already there.
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If the ecosystem we're visiting already has life, our life might destroy that life.
I wonder if this is the wrong way to go about it. You could design a spacecraft so it's heat resistant, and then once it's fully assembled, stick it in an oven and heat it to say 200C and just let it sit for a couple of days, or however long it takes to heat all the way through.
I'm sure this would present some design challenges, but it doesn't seem to me like it would be insurmountable.
I'm sure this would present some design challenges, but it doesn't seem to me like it would be insurmountable.
Heating something doesn't necessarily kill all life:
https://www.nps.gov/yell/learn/nature/life-in-extreme-heat.h...
https://www.nps.gov/yell/learn/nature/life-in-extreme-heat.h...
I think you can pretty much kill anything if you heat your spacecraft enough. Of course, you might kill the spacecraft too. It might be very difficult indeed to destroy certain types of spores, and the "cook the spacecraft until they're all dead" approach might be possible but completely impractical for any real budget. Obviously any temperature that's hot enough to melt standard space-hardened circuit boards is going to be difficult. On the other hand, it sounds like the clean room approach is no panacea either.
As an interesting tangent, the engineering used to design a heat-resistant spacecraft might be re-used to design a long-lived Venus surface probe.
As an interesting tangent, the engineering used to design a heat-resistant spacecraft might be re-used to design a long-lived Venus surface probe.
1) Ralstonia pickettii doesn't really need much to eat, and thus thrives in ultra-pure water systems. Like, you know, the ones used to make medical devices.
2) Stuff in the Burkholderia cepacia complex is naturally resistant to lots of antibiotics, but also tolerates chlorhexidine gluconate and various quaternary ammonium disinfectants. Well, ok, more than tolerates - they'll happily colonize the disinfectant solutions, and then infect whatever you're trying to "disinfect".
3) Deinococcus radiodurans seems almost engineered to survive interstellar travel, but that's probably just a coincidence. Anything that can survive 15,000 Gray is scary.
4) Bacillus altitudinis is pretty weird too - like the name says, it's been found up to 40ish-km, which is an odd place for things to grow.