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Old January 12th 18, 07:00 PM posted to sci.astro.research
Martin Brown[_3_]
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On 12/01/2018 11:27, Steve Willner wrote:
In article ,
jacobnavia writes:
There are no specific sensors looking for life in [Mars rovers]
(there isn't even a microscope),


[[Mod. note -- Some experiments specifically designed to look for life
were landed on Mars in 1976. They found some surprising chemistry, but
no unambiguous evidence of life:
https://en.wikipedia.org/wiki/Viking_program

The underlying engineering problem is that while detecting macroscopic
life is fairly easy (take pictures of it), detecting *microscopic* life
requires fairly heavy/bulky equipment which is normally designed to be
operated directly by skilled humans. So doing this by remote control
from 45 light-minutes away (and with zero ability for a human to fix
anything that doesn't work) is hard, i.e., difficult to develop and
make work properly. That difficulty means lots and lots of engineering
person-years to develop the mission, which makes the mission very
expensive (on a scale of planetary-science budgets).


I thought there was a project underway to send a small stable isotope
mass spectrometer to look for any variation of deltaC13 or deltaS34 in
the rocks that would be indicative of life. Life preferentially
concentrates the lighter isotopes making inorganic materials have a
higher concentration of the heavier isotopes. eg.

https://ntrs.nasa.gov/archive/nasa/c...9890016972.pdf

The challenge is making one that can survive the stresses of launch
without being to heavy and do its own sample prep. Increasing AI power
will make it possible sooner rather than later but I expect there may be
a few disappointments along the way. Mars with its very thin atmosphere
is particularly hard to do a soft landing on.

Some of the historic articles about what the Viking mission achieved
with its mass spectrometers is online at:

http://onlinelibrary.wiley.com/doi/10.1002/jms.396/full

Given a budget of (say) 5e9 {US$,Euro}/year, one could do some very
sophisticated searches for life on Mars. But the actual worldwide budget
for all Martian exploration is well under 0.5e-9 {US$,Euro}/year, so
progress is slow.

And despite what optimists like Zubrin/Musk might say, sending (living)
humans to Mars wouldn't be cheap, either.
-- jt]]


Sending humans to Mars would be more like "Big Brother" with teeth. You
would also have to send a substantial robotic automated medical facility
there to give them rehab when they arrived. Easier, cheaper and much
less risky all around to send smart autonomous robust robotic probes.

Life has metabolism, and the effects of that metabolism are gases that
are produced as side effects of being alive. Methane is one such a gas.


I wouldn't mind seeing a chiral labeled release experiment sent to
Mars, but so far it hasn't ranked high enough in the priority lists.


I think there were plans to send something using stable isotope labelled
likely foods and look for the characteristic signs of life in the waste
gasses. The challenge is as ever in distinguishing between inorganic
peroxide soil reactions and actual life metabolic processes. The idea
was that the observed isotope ratios would be different.

It would be extremely exciting to find independent life evolved anywhere
else in the solar system - although we need to take great care not to
contaminate pristine planetary environments with our own form of life.
ISTR some bacteria on the lunar lander Surveyor 3 that Apollo 12 visited
were still viable after 3 years on the moon.

https://science.nasa.gov/science-new.../ast01sep98_1/

--
Regards,
Martin Brown