Single biggest obstacle to Earth bacteria thriving on Mars

[BillTre]

I just wonder what all the worry is about then that our Mars landers are sufficiently sterilized before launch. Scientists must think there is at least some chance that microbes could survive there.

Although they go to great lengths to sterilize their Martian probes, I don't think NASA thinks they are actually sterile (nothing alive on them).
This is why they don't have their current rovers go to nearby areas where they think the ground is wet with water.

 

[Ygggdrasil]

Here's a nice review article from a scientific journal on the subject:
Moissl-Eichinger et al. 2016 Venturing into new realms? Microorganisms in space. FEMS Microbiol Rev 40: 722. http://dx.doi.org/10.1093/femsre/fuw015

An important concept in space microbiology or astrobiology is ‘habitability’, which is essentially an assessment of whether an environment can support the activity of a given organism, where activity might be maintenance, growth or reproduction. Due to the fact that we have only one example of a life-bearing planet so far, these considerations are restricted to life as we know it, even, if in some theoretical studies a broader approach has been considered (Baross 2006). For an environment in any location on Earth or elsewhere to be habitable, it must have several characteristics. They are:

• availability of water, at least temporarily in a liquid state,
• appropriate temperature conditions,
• availability of an energy source,
• carbon plus major other elements required by all known life forms (HNOPS) and
• other elements required by a specific organism as trace elements.

https://academic.oup.com/femsre/article-lookup/doi/10.1093/femsre/fuw015

The article explores the limits of these conditions in known terrestrial organisms both under natural and experimental conditions as well as discusses the conditions on Mars.

 

[Pythagorean]

Nobody's brought up water bears yet?!

 

[BillTre]

Nobody's brought up water bears yet?!

from wikipedia: Tardigrades are prevalent in mosses and lichens and feed on plant cells, algae, and small invertebrates.

They might survive the trip but would not have a food source on Mars.

 

[Comeback City]

They might survive the trip but would not have a food source on Mars.

Let them eat cake!

 

[BenAS]

Let them eat cake!

The cake is a lie

 

[Comeback City]

The cake is a lie

Cake is a lie? Oh the government has got us again...

 

[infinitebubble]

http://www.iflscience.com/space/marine-plankton-found-surface-international-space-station/

Scientists examining samples taken from the exterior of the International Space Station (ISS) have made a rather unexpected discovery- traces of marine plankton and other microbes growing on the surface of the illuminators. What’s more, it seems they could have been living there for years.

The intriguing discovery was made after ISS cosmonauts took surface samples during a routine spacewalk around the satellite. The samples were later analyzed by high-precision equipment as part of a so-called “Test” experiment, ITAR-TASS revealed. Scientists were then able to confirm that these organisms are capable of living in space despite the hostile conditions experienced. Furthermore, some of the studies demonstrated that the organisms could even develop in the vacuum of space.

How could such plankton survive and if so could such organisms be inoculating planets such as Mars and our Moon without us knowing? Could the rovers on Mars be swamped with this plankton borne from Earth or is this plankton already in space awaiting to attach itself to satellites, ISS, and other manmade objects?

 

[rootone]

They are described as 'marine plankton and other microbes', which must mean that they have been identified as known organisms found on Earth.
How they got there is puzzling, but the idea of organisms evolving in space independently of Earth, but apparently the same species seems very unlkely to me

 

[Comeback City]

the idea of organisms evolving in space independently of Earth, but apparently the same species seems very unlkely to me

It's basically as close as you can get to impossible.

 

[BillTre]

traces of marine plankton and other microbes growing on the surface of the illuminators.

How could such plankton survive

If they are actually growing, they would need some additional chemical input (like CO₂ or a carbon source and water) to build new cells.
I wonder if they could get some of that in traces from exhalations from the space station (like in urine dumps) which might condense of the ISS surface.

 

[willem2]

But can it survive without oxygen and liquid water?

It may be able to survive, but it can't eat. More from the Wikipedia article:

it uses oxygen to derive energy from organic compounds in its environment

 

[infinitebubble]

There is of course corrosion in space due to atomic oxygen... Citation: https://www.nasa.gov/topics/technology/features/atomic_oxygen.html

If so these microbes could be harnessing either the corrosion side effects of atomic oxygen or have evolved to use atomic oxygen (conjecture).

 

[Al_]

Although they go to great lengths to sterilize their Martian probes, I don't think NASA thinks they are actually sterile (nothing alive on them).
This is why they don't have their current rovers go to nearby areas where they think the ground is wet with water.

Really?
All the money and time and effort to get there, and they can't even go to the most interesting places?
Oh come on NASA seriously!
Can't they just figure a way to make it properly hygenic, how hard can it be for smart people like that?

 

[Drakkith]

Can't they just figure a way to make it properly hygenic, how hard can it be for smart people like that?

It is unimaginably difficult. Not only is the outside of the spacecraft and rover covered in microbes, but so is every component, every nook and cranny, every cable, every wheel bearing, everything. And even if you sterilize it completely, as soon as you take it out of the chamber or wherever it is that you sterilized it to get it ready for launch, it gets contaminated all over again!

 

[mfb]

The only reliable way to make something 100% microbe-free is to melt it completely.
The Viking landers were sterilized by heating the whole spacecraft . That gets rid of most microbes, but then every single component has to survive that temperature - which makes the construction more expensive. The current Mars rovers are complex even without adding such a high thermal resistance. It was decided to use weaker sterilization techniques, and to avoid the regions where life could potentially exist today.

 

[BillTre]

An autoclave works pretty well, but would tends to be destructive to many materials.

Another approach might be something like vaporized hydrogen peroxide, which can be compatible with electronics but is effective at killing things. However, chemical approaches might miss out on killing particular resistant organisms and is more difficult to apply to things with lots of small intricate spaces. Seems that these could just be sealed up or encased.

A possible different approach would be sampling from a distance. One might shoot (or rocket propel) a tube attached to the rover by something like a steel line. A hatch on the tube would close upon impact (as some seafloor samplers work), capturing a sample and then reeled back to the rover. Being structurally simple and materially resistant, it could be easily sterilized by heat or chemicals (possibly even on site) in an enclosed container just prior to being shot out.

Because its shooting something out it might even qualify for military funding.

 

[Ygggdrasil]

An autoclave works pretty well, but would tends to be destructive to many materials.

Various thermophilic archaea can survive autoclave temperatures (for example, https://en.wikipedia.org/wiki/Strain_121). We don't worry about them in most medical applications because they generally aren't infectious (i.e. they won't out-compete our natural fauna at 37°C), but they would absolutely be a concern for interplanetary contamination.

 

[plschwartzx]

Don't think current. Think past. Bacteria have been around for a long time. Including those living in rocks. Mars as we now know once had liquid water. And liquid- water temperature areas. It seems to me that meteor strikes would have sent Earth bacteria laden rocks toward Mars. So I do expect within Martian rocks we will find earth-derived bacteria.,
And if self replication is the first step toward life, and self-replicating molecules can be produced in an aqueous environment with a proper electro-chemical environment, who knows what else we might find in Martian rocks!

 

[syhprum1]

I understand that bacteria were found on a TV camera that was returned from the Moon by one of the Apollo misions

 

[Drakkith]

I understand that bacteria were found on a TV camera that was returned from the Moon by one of the Apollo misions

If true, those bacteria are almost certainly from Earth and simply contaminated the camera prior to or just after the mission.

 

[Comeback City]

If true, those bacteria are almost certainly from Earth and simply contaminated the camera prior to or just after the mission.

Yes, and otherwise this would've been HUGE news and the bacteria would've probably got half a dozen sponsorships and shoe contracts already

 

[Arman777]

Theres a bactery called tardigrada I think it can survive on mars

 

[Drakkith]

Theres a bactery called tardigrada I think it can survive on mars

You mean tardigrade? It's an animal, not a bacteria, and it could probably survive on Mars in a dormant state but it would not be able to live and reproduce.

 

[Arman777]

You mean tardigrade? It's an animal, not a bacteria, and it could probably survive on Mars in a dormant state but it would not be able to live and reproduce.

Yeah,I mean that..Oh sorry I didnt much give attention that its bacteria or animal.I see

 

[Al_]

It is unimaginably difficult. Not only is the outside of the spacecraft and rover covered in microbes, but so is every component, every nook and cranny, every cable, every wheel bearing, everything. And even if you sterilize it completely, as soon as you take it out of the chamber or wherever it is that you sterilized it to get it ready for launch, it gets contaminated all over again!

Why don't they sterilise it in an orbiting chamber?

Thnigs that are too delicate like electronics can be sealed inside plastic blocks, and you just sterilise the outside.

 

[Drakkith]

Why don't they sterilise it in an orbiting chamber?

They'd have to build one and put it in orbit for one thing. Which is costly and provides its own set of challenges. Now everything they'd have done on the ground has to be done remotely in space.

Thnigs that are too delicate like electronics can be sealed inside plastic blocks, and you just sterilise the outside.

Sure, but that may add weight and complications to the design. Both of which are the last things you want when designing a remotely controlled rover that has to be launched into space and then landed on another planet. I'm sure NASA did the best they could given the very tight constraints.

 

[Stormbringer]

water bears (or tardigrades) which are a macroscopic animal could probably survive. there probably is at least occasionally liquid water on Mars. The water bear could do what it needs to do when the water is present before it sublimates or is re-frozen. It can survive both the intense cold and heat of empty space. It can survive hard vacuum. It can survive severe radiation. I don't think it gives much of a darn about Ph or most toxins either. The primary problem would probably be getting it's food to survive to sustain it. Though possibly cannibalism for some species of tardigrade might be a temporary possibility. The problem is that the water bear would eventually starve or else be forced to permanent dormancy. You'd still need an algae or moss or lichen or fungi or other suitable food that was capable of surviving in order to create a closed life cycle/food chain for the 'bear. Otherwise the tough little tardigrade would probably just "shoot the bird" at the martian environmental challenge.

And if Mars is slightly too tough for the water bear to be able to form a closed cycle food web then the liquid water oceans of Europa and similar places would almost certainly not be.

 

[Drakkith]

And if Mars is slightly too tough for the water bear to be able to form a closed cycle food web then the liquid water oceans of Europa and similar places would almost certainly not be.

I disagree. The tardigrade would almost certainly be unable to survive on another world. And by 'survive' I mean live and reproduce in a sustainable population, not just remain dormant. Both Mars and those other worlds have no food and little or no air and there is nothing the tardigrade can do to change this.

 

[BillTre]

Here is a news article from Science magazine ow about how some tough Earth bacteria are killed pretty well by UV such would be found in sunlight on Mars.
However, bacteria could still hide in dark areas.