
Mars Methane Hunt Comes Up Empty, Flummoxing Scientists - pseudolus
https://www.scientificamerican.com/article/mars-methane-hunt-comes-up-empty-flummoxing-scientists/
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skosch
This made me go "huh, then how do they know their sensor is working at all?"

The answer is that the sensors are two spectrometers that detect all sorts of
gases, not just methane:

[0]
[https://en.wikipedia.org/wiki/Nadir_and_Occultation_for_Mars...](https://en.wikipedia.org/wiki/Nadir_and_Occultation_for_Mars_Discovery)

[1]
[https://en.wikipedia.org/wiki/Atmospheric_Chemistry_Suite](https://en.wikipedia.org/wiki/Atmospheric_Chemistry_Suite)

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nigwil_
Subtitle is a better heading and less border-line click-bait:

"Trace Gas Orbiter spacecraft did not find the gas in red planet’s atmosphere
during its first months of operation"

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KnightOfWords
Flummoxed is pretty fair in this case. The expectation is that any methane
released into the Martian atmosphere should persist on long timescales. Either
there is a unknown process which scrubs it quickly or previous measurements
were in error.

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ComputerGuru
But isn't that par for the course when it comes to methane on Mars?

It's been detected before at astronomical (heh) levels with subsequent
readings the very next day indicating only trace amounts.

[https://earthsky.org/space/methane-spike-june-2013-both-
curi...](https://earthsky.org/space/methane-spike-june-2013-both-curiosity-
mars-express)

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ChuckMcM
At some point I'd love a developer to use 'flummoxed' in their status update
:-)

The methane question is an interesting one and for me an example of how hard
it is to re-purpose science missions when you don't have a human there to
implement the new experiment. I feel that it illustrates the limits of robotic
exploration for now.

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londons_explore
Gas spectrometers are really very universal instruments. There's a lot of
experiments you can do with one, especially if you're happy to use an arc to
vaporise bits of solids and test the gasses that come off.

~~~
ChuckMcM
Hard to do that from orbit though, getting those solid bits up there takes
some work. And when you're on the ground if you're relying on auto-navigation
your average speed is less than 1km/day so hard to get a wide survey.

Take the current curiosity mission as an exemplar. It is coming up on having
been on the ground for 7 years (August '12). A human team, with the same
instruments, and a rover could have achieved all of the science results from
Curiosity to date, in less than a month. Further they could have repaired
instruments that have become non-functional from spares carried with them.

Opportunity and Spirit covered a combined 36 miles or so in 10+ years of
operations, also doable in about a month by a human crew.

So we have nearly two decades of robotic exploration that we could do in about
3 months with a group of people and some transport. Plus they could do
additional research that the robots can't because they could combine the
instruments in ways the robots cannot, or use different processes the robotics
cannot implement.

I realize this sounds like a dismissal of the huge accomplishment and
contribution to science that the rovers have made. It is not my intent. Those
are valuable things, and some science is always better than no science. What
I'm trying to point out that putting people there would have 100x the science
return for less than 100x the budgetary impact.

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mjevans
The simplest explanation that I can think of is that some form of methane is
trapped in geologic formations which periodically release (such as ice), but
that the mentioned chemical/dust reactions end up sequestering (scrubbing) it
in to more solid forms that are harder to detect.

Mars would be a much more interesting place if we'd send over enough
infrastructure to get mostly autonomous robots going and scaling up local
infrastructure for some kind of terra-forming effort.

~~~
zamalek
A solid [heh] explanation. The methane could simply be absent because of
seasons. It has very slightly larger axial tilt than Earth, and a far greater
eccentricity. The sun could just be liberating methane from geological
formations during the correct conditions (close to the sun, and in summer).

Seasons could also affect life (just like it does plants on Earth), but it's
never aliens.

Mars is currently at its aphelion and the southern ice cap is not receiving
sunlight, so anything liberating Methane might be inert.

> the mentioned chemical/dust reactions end up sequestering (scrubbing)

A good explanation, there is another possibility. Given that CO2 (the main
component of the Martian atmosphere) is _so_ much heavier than methane, the
minuscule concentration could have floated to the top of the atmosphere and
could have been mostly blown away by solar wind. Methane could still be there,
just far below the noise floor.

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tdy721
Both of you make good points, I just want to point out that since the mission
has been observing mostly during a period of intense dust storm activity. If a
dust scrubbing effect is real, the orbiter may still have a chance at
detection.

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jbotz
That's funny... just a few days ago the Europeans (Mars Express) were
"definitely finally confirming methane on Mars... now the Americans are saying
"nope" without directly addressing the Mars Express findings?

See: [http://www.astronomy.com/news/2019/04/astronomers-finally-
co...](http://www.astronomy.com/news/2019/04/astronomers-finally-confirm-
methane-on-mars)

~~~
simcop2387
This back and forth about methane on mars has been going on for a while. Not
divided politically either, the US has gotten both results over various
missions. The speculation I've heard about this is that the methane isn't
global and isn't being released constantly, leading to confusing readings.

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iamshs
Methane and Mars story consumed India‘s MOM too:

[https://www.seeker.com/india-mars-orbiter-mission-methane-
de...](https://www.seeker.com/india-mars-orbiter-mission-methane-detector-
flaw-red-planet-2133861312.html)

[https://thewire.in/85859/methane-isro-msm-
spectroscopy/](https://thewire.in/85859/methane-isro-msm-spectroscopy/)

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kochikame
Aliens

