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with which one can obtain detailed astrobiological information below micrometer
scale. NMR spectrometers are big equipment, but there are already miniature,
lightweight, NMR spectrometers being developed at NASA-JPL which do not
contain permanent magnets (they are designed to operate without applied magnetic
fields); instead, they exploit the natural magnetic fields of the mineral phases (that
contain iron) to be studied.
These fields give rise to nuclear magnetic resonance of the isotope
57
Fe at
frequencies in the approximate range of 60-74 MHz in magnetite (Fe
3
O
4
). Such
instrument has a mass of only 65 g - with a 5 V DC battery included - and consumes
a power of only 0.5 W. It will be interesting the use of miniature NMR spectroscopy
at Mars.
This instrument includes a marginal oscillator, the frequency of which is
determined mainly by tuning capacitors, two varactors, and the NMR sample coil,
in which a mineral specimen is placed. During operation, the frequency is swept
slowly by use of one varactor and is modulated at a rate of 110 Hz by the use of the
other varactor. The instrument also includes a digital-to-analog and an analog-to-
digital converter and a microprocessor that communicates with an external laptop
computer, generates frequency sweep and modulation signals, samples the output
from the oscillator, and performs synchronous detection. Spectral data can be
displayed on the computer screen. The software in the computer includes routines
for processing data to estimate concentrations of mineral phases of interest. The per-
formance of the instrument was demonstrated in NMR measurement experiments on
two mineral specimens: one that contained magnetite in chlorite schist mixed with
magnetically inert particles and one made of hematite (a-Fe
2
O
3
)(Kimetal.
2009
).
Mössbauer (MB) spectrometers are very useful in planetary exploration, and such
NMR spectrometer can be a useful tool for complementing data from MB ones. So,
with the objective of the search for hypothetical extinct or extant life on the “Red
Planet,” I propose that in future robotic missions and a possible manned research at
Mars, miniature NMR spectrometers be used.
Rovers can use their robotic arms to collect soil and rocky samples from
below surfaces and put them inside the spacecraft where such those spectrometers
can analyze the material. And astronauts can also use those miniature NMR
spectrometers to do in situ very good quality research of surface and subsurface
minerals, searching for biologically important minerals, organic molecules, and
morphological structures relevant for astrobiology.
8.8
Hypothetical Future Life on the “Red Planet”: Mars
Colonization and Terraforming
Do little green men exist on Mars?
Well, no one knows the answer to this question. But, perhaps, this question
could be reformulated as follows: will men exist on Mars? And the answer is
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