Scientific Colloquium
March 19, 2010
SUZANNE YOUNG
UNIVERSITY OF MASSACHUSETTS
"The Phoenix Mission
to Mars: Top Ten Discoveries of NASA’s Innovative Explorer of the
Red Planet
and the Implications for Bio-habitability"
The 2007 Phoenix Mars Scout lander
launched on 4 August 2007 and landed on 25 May 2009 at the northern
polar latitude of 68.22°N, and longitude 234.25°E
(areocentric). The landing site was a field of sand wedge polygonal
terrain. For 152 sols the mission made extensive atmospheric and ground
measurements. Analyses included interacting with and excavating the
Mars regolith with a robotic arm and delivering samples to payload
instruments including microscopes (optical and atomic force), a
scanning calorimeter-mass spectrometer (TEGA) and an electrochemical
analyzer, (WCL). TEGA confirmed the presence of water ice in the
regolith, not bound as a chemical ligand. The salts discovered by WCL
offer evidence for the presence in the past of liquid water on
Mars. The presentation will include information about these, as
well as, other amazing discoveries on Mars. Sources of bio-energy, key
bio-elements and ions, and environmental toxicity and pH will also be
discussed with our current understanding of the red planet.
The mission had a goal of sampling to determine whether this
environment may have been habitable for life at some time in its
history. Given our current understanding of life, the potential
for habitability in a specific time and space encompasses three
factors: (1) the presence of liquid water, (2) the presence of a
biologically available energy source, and (3) the presence of the
chemical building blocks of life (e.g. C, H, N, O, P, S) in a
biologically available form. (Additional ions, vital to all life as it
is known on Earth, worth examining include K+, Na+, Ca2+, Mg2+, Cl-,
Fe2+/3+, NO3-, NO2-, NH4+, SO42-, PO43-.) In addition to these
factors, temperature and water activity must be high enough to support
growth. An environment also must be sufficiently benign as to not
destroy life attempting development or habitation. These factors must
be simultaneously present. The only way to explore all these
factors in one location is to send a suite of instruments. The
Phoenix mission sent such a suite to Mars. An evaluation of
habitability is a precursor requirement for sending any mission to
search for life, thus the major discoveries of the mission will be
discussed in evaluation of these requirements for life.