Nasa's most recent Mars missions have always featured a
common theme: follow the water. But the agency's third rover, which
will set off for the red planet later this year, will re-run the
mission of the 1976 twin Viking landers: seek
the building blocks of life.
But with the original reports from Viking coming back
negative for organic chemicals -- elements like carbon which are
needed to sustain life -- what makes Nasa believe Curiosity will
have any more luck?
Well, for one, the $2.3 billion rover will pick better locations. Mars' landscape is diverse
and Curiosity will plunge into areas with exposures of clay and
sulphate minerals, which are good at entrapping organic chemicals.
If it's not in the right spot, enhanced mobility and a better
understanding of the planet's layout means the rover can use mapped
geologic context to find a better location.
It can also analyse samples from the interiors of rocks with
its drill, whereas Viking was stuck with soil samples.
But more importantly, the new vehicle is equipped with
instruments and equipment that are considerably more advanced than
the 70s landers. "We've taken a set of experiments that would
occupy a good portion of a room on Earth and put them into that box
the size of a microwave oven," said Paul Mahaffy of Nasa's Goddard Space
One of those tools is a mass spectrometer, which identifies
gases by the molecular weight and electrical charge of their
ionised states. This will check for elements like nitrogen,
phosphorous, sulphur, oxygen and carbon, which are all important
for life as we know it.
Another tool is a laser spectrometer, which uses absorption
of light at specific wavelengths to measure concentrations of
specific chemicals. It also identifies the proportions of different
isotopes (variants of the same element, but with different atomic
weight), which can hint at past planetary processes. This tool will
look at the history, concentration and activity of the organic
Curiosity's third analytical tool is a gas chromatograph,
which separates different gases from a mixture to aid
These advanced tools give the rover highly improved sensitivity, and a capability to detect
less than one part per billion of an organic compound, over a wider
mass range of molecules and after heating those samples to a much
"If we do find detectable organics, that would be an
encouraging sign that the immediate environment in the rocks we're
sampling is preserving these clues," said Mahaffy. "Then we would
use the tools we have to try to determine where the organics may have come from." A future mission could bring a
sample back to Earth for more extensive analysis.
Nasa will launch Curiosity from Cape Canaveral in Florida
between 25 November and 18 December 2011, as part of the Mars
Science Laboratory mission's spacecraft.