Curiosity rover finds clues to changes in Mars' atmosphere

Nov 02, 2012
This picture shows a lab demonstration of the measurement chamber inside the Tunable Laser Spectrometer, an instrument that is part of the Sample Analysis at Mars investigation on NASA's Curiosity rover. This demonstration uses visible lasers – rather than the infrared ones on the actual spectrometer – to show how the lasers bounce between the mirrors in the measurement chamber. The TLS shoots laser beams into a type of measurement chamber that can be filled with Mars air. By measuring the absorption of light at specific wavelengths, the tool can measure concentrations of methane, carbon dioxide and water vapor in the Martian atmosphere and different isotopes of those gases. Image credit: NASA/JPL-Caltech

(Phys.org)—NASA's car-sized rover, Curiosity, has taken significant steps toward understanding how Mars may have lost much of its original atmosphere.

Learning what happened to the Martian atmosphere will help scientists assess whether the planet ever was habitable. The present is 100 times thinner than Earth's.

A set of instruments aboard the rover has ingested and analyzed samples of the atmosphere collected near the "Rocknest" site in Gale Crater where the rover is stopped for research. Findings from the Sample Analysis at Mars (SAM) instruments suggest that loss of a fraction of the atmosphere, resulting from a physical process favoring retention of heavier of certain elements, has been a significant factor in the evolution of the planet. Isotopes are variants of the same element with different .

Initial SAM results show an increase of five percent in heavier in the compared to estimates of the isotopic ratios present when Mars formed. These enriched ratios of heavier isotopes to lighter ones suggest the top of the atmosphere may have been lost to . Losses at the top of the atmosphere would deplete lighter isotopes. Isotopes of also show enrichment of the heavy isotope, matching previous estimates of atmosphere composition derived from studies of on Earth.

This graph shows the percentage abundance of five gases in the atmosphere of Mars, as measured by the Quadrupole Mass Spectrometer instrument of the Sample Analysis at Mars instrument suite on NASA's Mars rover in October 2012. Image Credit: NASA/JPL-Caltech, SAM/GSFC

Scientists theorize that in Mars' distant past its environment may have been quite different, with persistent water and a thicker atmosphere. NASA's and Volatile Evolution, or MAVEN, mission will investigate possible losses from the when it arrives at Mars in 2014.

With these initial sniffs of Martian atmosphere, SAM also made the most sensitive measurements ever to search for methane gas on Mars. Preliminary results reveal little to no methane. Methane is of interest as a simple precursor chemical for life. On Earth, it can be produced by either biological or non-biological processes.

Methane has been difficult to detect from Earth or the current generation of Mars orbiters because the gas exists on Mars only in traces, if at all. The Tunable Laser Spectrometer (TLS) in SAM provides the first search conducted within the Martian atmosphere for this molecule. The initial SAM measurements place an upper limit of just a few parts methane per billion parts of Martian atmosphere, by volume, with enough uncertainty that the amount could be zero.

"Methane is clearly not an abundant gas at the Gale Crater site, if it is there at all. At this point in the mission we're just excited to be searching for it," said SAM TLS lead Chris Webster of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "While we determine upper limits on low values, atmospheric variability in the could yet hold surprises for us."

If the atmosphere of Mars contains methane, various possibilities have been proposed for where the methane could come from and how it could disappear. Potential non-biological sources for methane on Mars include comets, degradation of interplanetary dust particles by ultraviolet light, and interaction between water and rock. A potential biological source would be microbes, if microbes have ever lived on Mars. Potential sinks for removing methane from the atmosphere are photochemistry in the atmosphere and loss of methane to the surface. Image credit: NASA/JPL-Caltech, SAM/GSFC

In Curiosity's first three months on Mars, SAM has analyzed atmosphere samples with two laboratory methods. One is a mass spectrometer investigating the full range of atmospheric gases. The other, TLS, has focused on carbon dioxide and methane. During its two-year prime mission, the rover also will use an instrument called a gas chromatograph that separates and identifies gases. The instrument also will analyze samples of soil and rock, as well as more samples.

"With these first atmospheric measurements we already can see the power of having a complex chemical laboratory like SAM on the surface of Mars," said SAM Principal Investigator Paul Mahaffy of NASA's Goddard Space Flight Center in Greenbelt, Md. "Both atmospheric and solid sample analyses are crucial for understanding Mars' habitability."

SAM is set to analyze its first solid sample in the coming weeks, beginning the search for organic compounds in the rocks and soils of Gale Crater. Analyzing water-bearing minerals and searching for and analyzing carbonates are high priorities for upcoming SAM solid sample analyses.

Researchers are using Curiosity's 10 instruments to investigate whether areas in Gale Crater ever offered environmental conditions favorable for microbial life. JPL, a division of the California Institute of Technology in Pasadena, manages the project for 's Science Mission Directorate, Washington, and built Curiosity. The SAM instrument was developed at Goddard with instrument contributions from Goddard, JPL and the University of Paris in France.

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Torbjorn_Larsson_OM
5 / 5 (2) Nov 02, 2012
Finally! We have waited for the 1st sample long enough (a few weeks), and I was afraid the 2nd sample would be delayed too because of problems to understand the result.

Maybe there was such a delay previously, but from here it seems the (seeming) absence of methane may have been controversial as well.

All is well that ends well. Atmospheric loss was predicted, and it will be interesting to see the papers modeling atmosphere over time. Seems to me some oxygen is released by UV on ice, as would be expected (not matching the CO abundance). This is a good model for how Earth may have gotten its first, then highly toxic, oxygen into the atmosphere.
antialias_physorg
2.2 / 5 (5) Nov 02, 2012
The present atmosphere of Mars is 100 times thinner than Earth's.

That, at the very least, should lay any ideas about terraforming Mars to rest. Yeah, we could put down biologicals that would sequester CO2 and release O2 - but the atmosphere would still be way too thin to be of any use to humans.
Torbjorn_Larsson_OM
4.3 / 5 (3) Nov 02, 2012
As I remember it, if one heat up Mars it would have a semi-breathable atmosphere after letting plants et cetera have a go at the CO2/CO, at ~ 1/3 of Earth atmosphere pressure.

One way of heating it would be to smack it with asteroids, which would deliver more volatiles. (Most common asteroids, carbonaceous chondrites, average ~ 10 % water.) The "Red/Green/Blue Mars" series of books describes one pathway, including genetic engineering to get away with the marginal pressure, and was based on then available facts AFAIK.

Is it doable? Mankind have done generational projects before, if city building et cetera counts. Presumably then, given the right economics. At the very least it could be a planetary greenhouse for food with pressurized homes for living.
antialias_physorg
3.7 / 5 (3) Nov 03, 2012
if one heat up Mars it would have a semi-breathable atmosphere after letting plants et cetera have a go at the CO2/CO, at ~ 1/3 of Earth atmosphere pressure.

That's not breathable. The pressure on mount everest is 70% of what it is at sea level. And you already need gear to survive that for any length of time.

Anyhow: Anything beyond 7% CO2 will knock a human out (at 1.5% you already have impaired mental functions). Mars atmosphere is 95% CO2. We'd need to convert enough CO2 into O2 AND replace more than 70% with inert gases (e.g. N2 or halogens which are nowhere to be had on Mars) AND up the volume/pressure (AND up the temperature AND up the radiation protection AND up the gravity AND ...)

I dunno, but from an engineering standpoint that sounds just a tad bit out of our league. Certainly seems more complicated than just 'letting plants have a go'.
marble89
1 / 5 (1) Nov 03, 2012
Recent Mars Climate models are not very encouraging on the terraforming issue. It now appears that if we try to increase the mass and temperature of the atmosphere by adding more Co2 a negative feedback will occur: In short, additional mass creates thicker seasonal CO2 caps during high obliquity periods which are more difficult to sublimate in the spring. This increases the planetary albedo which cools the atmosphere which causes more co2 to freeze out .... We get a runaway process where almost the entire atmosphere collapses onto the surface
Pkunk_
3 / 5 (2) Nov 03, 2012
I dunno, but from an engineering standpoint that sounds just a tad bit out of our league. Certainly seems more complicated than just 'letting plants have a go'.

It's far easier to just take the Total recall route with large domes and pressurized underground caverns.
MrVibrating
not rated yet Nov 03, 2012
...if we try to increase the mass and temperature of the atmosphere by adding more Co2 a negative feedback will occur: In short, additional mass creates thicker seasonal CO2 caps during high obliquity periods which are more difficult to sublimate in the spring. This increases the planetary albedo which cools the atmosphere which causes more co2 to freeze out .... We get a runaway process where almost the entire atmosphere collapses onto the surface

Then perhaps we might use more potent greenhouse gasses - such as sulfur hexaflouride (orders of magnitude more effective). The concentrations needn't be anywhere near as high, and any synthetic organisms used could have toxicity resistance engineered in. That takes care of temperature; mass is another matter. Asteroid bombardment seems the most obvious medium there - with help from upper atmosphere ionisation (ie. the lack of magnetosphere could work for, rather than against us, on that count)...
Sanescience
4 / 5 (2) Nov 03, 2012
The inference I made was Mars can't retain an atmosphere. Probably a combination of low gravity and no magnetic field lets the solar wind strip it away.

As for the idea of terraforming Mars, or anything, that is probably going to loose out to developments in adapting humans to hostile environments. Certainly it would be more efficient if humans developed virtual telepresence technologies and can live in their habitats while they operate their robots as if they were there themselves.

That way you not only avoid the inefficiency and waste of supporting human life where ever it goes, but can experience the beauty of the universe "in person" as it exists naturally.
aironeous
not rated yet Nov 03, 2012
The present atmosphere of Mars is 100 times thinner than Earth's.

That, at the very least, should lay any ideas about terraforming Mars to rest. Yeah, we could put down biologicals that would sequester CO2 and release O2 - but the atmosphere would still be way too thin to be of any use to humans.

Wow that is a very negative defeatist view. Look at the regolith, it is all rust. There is tons of oxygen in that regolith. Give me geobacter metallireducens and some underground farming structures and tunnels and power and I'll make vinegar to turn all that red iron oxide to magnetitite decreasing the albedo which warms the ground releasing more co2 and give me some digging rovers to bring me ice and a year supply of carbon rods and I'll turn that ice into magnegas, save the H2 for fuel cells in living quarters, vent the CO (which won't freeze out or breakdown quickly) to the crater thickening the atmosphere and get to work on PFC's.
aironeous
not rated yet Nov 03, 2012
Recent Mars Climate models are not very encouraging on the terraforming issue....

That is why we need to use geobacter metallireducens and vinegar made by the colonists (possibly distributed by rover incubators) to turn the red rust into magnetite. Combined with PFC's and colonists converting ice into magnegas and venting the CO this is a multi prong strategy to overwelm any freezing out.
Discarding asteroid mining tailings by throwing them at mars is also a small, steady contributing factor to increase warmth, gravity. Asteroid miners could also supply buffers gases in trade.
Starting an underground biosphere originating at the colonists site from human waste could give us a kickstart on creating a carbon and nitrogen cycle.
Future rovers, colonists could use v3solar type power sources.
antialias_physorg
3.7 / 5 (3) Nov 03, 2012
Wow that is a very negative defeatist view

No. Just realist. there are options for colonizing Mars. Enclosed habitats might work (though I still think the lack of sufficient gravity would doom that to failure. Human physiology is just not adaptable to constant low gravity conditions - especially not during the first 20 years of life)
We may have to think about altering ourselves if we want to live elsewhere (and even that is way beyond our capabilities right now).
From an engineering point of view terraforming is just wishful thinking. It makes for great scifi, but it's very far removed from any kind of realistic science.

The magnitude of turning an entire planet into something it isn't seems to escape you. This isn't scaling up a test tube experiment. This is MASSIVELY scaling up something that we couldn't even do on Earth. Think of how much we've done to just add 0.1% of CO2 to our atmosphere - and how long and what effort that took.
Mike_Massen
3.7 / 5 (3) Nov 05, 2012
antialias_physorg continues to express narrow views missing imagination (sigh)
From an engineering point of view terraforming is just wishful thinking. It makes for great scifi, but it's very far removed from any kind of realistic science.
Do you not consider we're living SciFi NOW ?

Negativity isnt helpful without really thinking of various scaffolding issues which are very likely to be far more complex than you can imagine.

We already have the beginnings of synthetic biology, there is also a developing skill re anhydrous bio forms and advanced forms of artificial selection algorithms etc.

- Money cycles round economies, far more useful to create than weaponise.
- Develop gel pods which contain bacteria, moisture, micro chemical factories that grow & reproduce.

We have yeast NOW that has been engineered to produce diesel. Based on the biological equivalent of moore's law the basic tech for terraforming is sneaking up quickly.

Be positive, diverse, please imagine with fun !
antialias_physorg
not rated yet Nov 05, 2012
antialias_physorg continues to express narrow views missing imagination (sigh)

There is a very rational train of thought behind this 'narrow view'

There are speculations as to what we may do that are sensible and there are those speculations which are not.

1) Scientific and technological abilities do progress at a fast but not limitless. The timeline from first inception of even a minor (scientific) idea to prioduct is a decade (and we're talking several MAJOR ideas when talking about terraforming)
2) Every now and then paradigms shift so vastly that predictions/ideas made before them are pointless (examples would be the steam engine, nuclear power, the internet, lasers ... )

The time horizon for a paradigm shift is (if history is any indication) currently on the order of 50 years (with a rather large uncertainty upwards but not much below that).
The timeframe for terraforming is vastly beyond that. So speculating on those is not sensible.

antialias_physorg
3 / 5 (2) Nov 05, 2012
Negativity isnt helpful

I agree. But building castles in the sky without reagard for real physics, biology, astronomy, economics, tech-level and so on is also not helpful. That's only cool for scifi.

anhydrous bio forms

Couldn't find that on google. What is that?

advanced forms of artificial selection algorithms

What exactly do you mean by this?

far more useful to create than weaponise

I agree wholeheartedly on this.

Develop gel pods which contain bacteria, moisture, micro chemical factories that grow & reproduce.

I think you still do not understand that we are talking about a PLANET here - and what kind of size that means. A fully (bacterial) life supporting planet (Earth) took BILLIONS of years to get the atmosphere to something we can breathe using optimally adapted self replicators. Under MUCH better initial conditions than Mars provides.
marble89
1 / 5 (1) Nov 05, 2012
...if we try to increase the mass and temperature of the atmosphere by adding more Co2 a negative feedback will occur: In short, additional mass creates thicker seasonal CO2 caps during high obliquity periods which are more difficult to sublimate in the spring. This increases the planetary albedo which cools the atmosphere which causes more co2 to freeze out .... We get a runaway process where almost the entire atmosphere collapses onto the surface

Then perhaps we might use more potent greenhouse gasses - such as sulfur hexaflouride (orders of magnitude more effective). The concentrations needn't be anywhere near as high, and any synthetic organisms used could have toxicity resistance engineered in. That takes care of temperature; mass is another matter.


Yes, using a high molecular weight synthetic greenhouse gas was the concept used in the Red/Green Mars trilogy. But it is the pressure broadening of spectral lines that matters and pressures on mars are far too low
antialias_physorg
not rated yet Nov 06, 2012
Then perhaps we might use more potent greenhouse gasses - such as sulfur hexaflouride

The amount you'd need to dump on there is in the trillion kg range to be effective (one trillion kg of sulfur hexafluoride would give you the same gloabl warming potential as the entire Martian atmosphere.)

Now call me 'negative', but I would argue that it is a tad bit out of our range of technical capabilities to ferry that kind of mass to Mars (and that it is likely to remain outside our range of capabilities for a couple of years, decades, centuries...even if we could manufacture that much sulfur hexafluoride on Earth at all. Current yearly production is 8 million kg. So if we could to dump all yearly production on Mars we'll get there in, oh, about a 100000 years.)

C'mon people. Do some math before posting stuff.
Mike_Massen
1 / 5 (1) Nov 06, 2012
antialias_physorg mumbled
Couldn't find that on google. What is that?
Thats one of your problems, relying on any search engine of populist sites. Get subscribed to peer review journals in diverse fields please.

- There are many ppl studying biotech with minimal water - hence anhydrous
- Artificial selection, surely thats obvious by way of software to choose optimum gene sequences then application to enforce mutations across the widest biochemical lab space.

I think you still do not understand that we are talking about a PLANET here...
(doh) start with knowledge in conjunction with imagination - the one eyed man in the kingdom of the ...

Once you have run the selection criteria, which includes procreation as high priority, use less sites, obviously easier where wetter - let nature do the rest.

Obviously many paths to explore but biotech is growing rapidly ;-)

Its the sophistication of combinatorial complexity that requires those that are positive & smart(er) !

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