Water discovered in Martian soil

(CNN) Scoop up some soil on Mars, heat
it up, cool down the steam and ... slurp,
slurp! You've got water!
Mars might appear dry as a desert, but
astronauts may someday be able to tap its
soil to quench their thirst. Research
recently published suggests that the soil
from the Martian surface contains about
2% water by weight.
This is one of several insights emerging
from data that the Mars rover Curiosity has
been collecting. Five studies in the journal
Science were published last week based on
data from the rover's first 100 days on the
Red Planet.
"The community was surprised that there
was a large amount of water trapped in
the ... Martian soil," said Chris Webster,
manager of NASA's Planetary Sciences
Instruments Office.
Curiosity, representing a $2.5 billion NASA
mission, has been on Mars since it made a
dramatic landing there August 6, 2012.
Earthlings celebrated as the two-ton rover
arrived, carrying with it the most
sophisticated suite of instruments and
cameras to explore the surface of another
planet.
Thanks to Curiosity, scientists
now know more than ever
about the composition of the
Martian soil.
"It's the first time that the soil
has been analyzed at this level
of accuracy," Webster said.
Turning on the faucet
The rover's Sample Analysis at
Mars (SAM) instrument helped
scientists probe the soil by
heating a sample up to 835
degrees Celsius.
The gases that came off included oxygen
and chlorine as well as water vapor. Based
on the ratio of isotopes within, scientists
believe this water is coming from the recent
Martian atmosphere.
"If you take about a cubic foot of dirt with
the amount of water that we found and
heated it up, you could get a couple of
pints of water out of that," said Laurie
Leshin, dean of science at Rensselaer
Polytechnic Institute in New York, who led
this study. "It was kind of exciting to me to
see that, wow, it would be a significant
amount."
More broadly, the analysis gives us new
information about the hydrological cycle on
Mars, said John Grotzinger, lead scientist
on the Curiosity mission.
"Somehow, there's a process on Mars
where, even though there are just trace
quantities of water in Mars's atmosphere,
this noncrystalline material is able to
absorb it like a sponge and bind it into its
framework," Grotzinger said.
The technical details about how future
astronauts would use the soil as a resource
for water haven't been worked out,
Webster said. A condenser would be
required to cool the water steam into a
liquid form after heating up the soil. But
from what we know so far, he said, it would
be drinkable.
"This is a reservoir for water on Mars that
we had not really appreciated before,"
Grotzinger said.
More than 100,000 want to go to Mars and
not return
Soil types
Scientists are also learning about the
diversity of the soil on Mars.
Pierre-Yves Meslin, a scientist at Universite
de Toulouse in Toulouse, France, and
colleagues used data from an instrument
that fires a laser to analyze the soil and
rock on Mars. It's called the ChemCam
Remote Micro-Imager.
One main soil type on Mars, they said, is
made of fine-grained particles and carries a
significant amount of hydrogen. Scientists
say this reflects the dust that covers the
whole Martian surface. The dust that covers
Mars is more akin to a fine sand than the
fluffy film on the floors of neglected attics
on Earth, Webster said.
The other main soil type was coarse and is
local to Gale Crater, the area where the
rover is exploring. These particles, up to 1
millimeter in size, reflects what rocks in this
area are made of.
Previous rovers -- Pathfinder, Spirit and
Opportunity -- had less sophisticated
technology to analyze soil but their insights
about the mineral composition of the
Martian soil are similar to what Curiosity
found, Meslin said.
With ChemCam and Curiosity's other
instruments, the latest rover can give
scientists a deeper understanding of the
composition, as well as how this soil was
formed.
Complications with organics
New scientific insights also present the
issue of chemical compounds that may
complicate the search for life on Mars.
Curiosity is not capable of detecting life
directly; it wouldn't confirm either modern
life or ancient fossil organisms. It can,
however, determine if the ancient
environment was habitable -- which the
rover told us it was -- and look for organic
compounds.
Finding those compounds wouldn't prove
the existence of life, either, because they
can come from other sources. But the
appearance of organic molecules would
suggest that the environment is good at
preserving them.
The release of chlorine and oxygen when
the rover heated up soil suggests the
presence of a chemical called perchlorate,
at a 0.5% level in the soil, Leshin said. This
substance can destroy organic carbon in a
chemical reaction when the rover heats up
soil. And so far, Curiosity has not directly
detected organics in the soil.
Potentially the rover could avoid this
problem using alternative techniques,
which wouldn't heat the soil so much that
perchlorates break down.
"Perchlorate is reacting with some organic
compound to produce these simple
molecules," Grotzinger said. "It leaves us
asking the question: Is this from Mars, or is
it something we brought with us? And right
now we don't know."
Perchlorate in the planet's abundant dust
could present a toxicity problem to humans
on Mars; on Earth, it's known to cause
thyroid problems, Leshin said.
The dust could generally pose a health
problem as well both physically
interfering with respiration and being a
chemical hazard. Mars is known to have
massive dust storms.
"It's one of the significant concerns to
human exploration," Webster said.
Still no methane
Scientists are interested in whether Mars
has methane gas, which could be an
indicator of the planet's habitability. About
90% to 95% of the methane in Earth's
atmosphere is biologically derived, said
Sushil Atreya, a University of Michigan
researcher and co-investigator for SAM,
said in November 2012.
But the rover still has not detected
methane gas, as scientists noted in Science
earlier in September.
Even if there were methane, nonbiological
sources such as volcanic activity can
produce it.
It's still possible that methane will turn up
in future measurements, however, Webster
said.
Studies: Martian atmosphere was destroyed
long ago
Where it's going now
Curiosity is about one-fifth of the way to
Mount Sharp, its final destination, where it
will climb while testing the peak's
sedimentary layers that have formed over
time. Mount Sharp is 3.4 miles high, and its
rock layers represent a series of chapters of
the planet's history and the environmental
conditions present in various eras.
Along the way, the rover stopped at a
location called Waypoint 1, where scientists
found a conglomerate rock that would have
been found in an ancient stream bed. The
rock with the pebbles has strange veins,
filled with material that scientists don't
quite understand.
"The implication of that is that again we're
seeing the involvement of water, and it
looks like this water was very widespread
across the landing area," Grotzinger said.
It appears that the river would have
extended from the rover's landing site all
the way to Waypoint 1. The entire area that
Curiosity has been driving across would
have been covered by a stream bed, at one
point or another, in the ancient history of
Mars.
Curiosity isn't the only moving human-
made object on Mars. The Opportunity
rover, which launched in 2004, is still
chugging along.
In 2020, NASA plans to send an even more
advanced rover to "explore and assess
Mars as a potential habitat for life, search
for signs of past life, collect carefully
selected samples for possible future return
to Earth, and demonstrate technology for
future human exploration of the Red
Planet."
NASA recently announced a competition for
proposals of what instruments the 2020
rover could carry.
It, too, may get humans closer to drinking
water, and possibly even showering, on
Mars.