The
world may be abuzz these days with the release of the movie "Harry Potter
and the Order of the Phoenix," but there is a real magical Phoenix in the news.
The
Phoenix Mars Mission, the first in NASA's "Scout Program", is set to
launch the first week in August 2007 for a 10 month journey to the northern
plains of Mars. Mars Scouts are low cost, competitively selected missions that
are intentionally outside the mainstream of NASA's Mars Exploration Program and
are the scrappy underdogs of the space world. Phoenix certainly fits this
description, and for those who are always tempted to root for the underdog, Phoenix is a great cause.
After
the very public failures of two NASA missions (Mars Climate Orbiter
and Mars
Polar Lander) in 1999, NASA set out to completely restructure the Mars
Exploration Program (MEP). Scott Hubbard (currently Carl Sagan Chair for the
Study of Life in the Universe, SETI Institute) was sent to NASA Headquarters
and dubbed NASA's "Mars Czar" in the press when he was chosen to head
the reorganization. Hubbard designed a program of alternating landers and
orbiters to take advantage of each two-year launch opportunity to Mars (when
Mars is in the right position in its trip around the sun to be more easily
reached from earth), and to have enough time between similar type missions to
take advantage of lessons learned. The strategy has worked very well, and the
Mars Exploration Program (MEP) has been amazingly successful since the
restructuring.
The
Mars Scout Program was created when Hubbard and the science community sought
opportunities for missions outside the main stream of the MEP. This program was
specifically established to provide an opportunity to capitalize on advancing
technologies and innovations as well as to give the broader scientific
community the ability to explore Mars. Even though Mars Scouts were intended to
be low cost, relatively straightforward missions, few things about space
exploration are ever simple or easy. The Phoenix mission development is no
exception. Most of the Phoenix mission is the rebirth (hence, the name Phoenix) of the Mars Polar Lander (MPL) that crashed onto Mars in 1999. As always, during
the development of any space mission lots
of hardware was built for all the tests and redundancies required to safely
fly a space mission. In addition, a follow-on mission to MPL had been planned,
and then cancelled, which left a further legacy of hardware. Some of the
instrumentation was usable on Phoenix, which made it ideally suited to uncover
the clues to the geologic history and biological potential of the Martian
arctic.
The
story of MECA, (Microscopy, Electrochemistry, and Conductivity Analyzer) which
includes a wet chemical analyzer with a dual-use microscope, is a great example
of how science instruments could be reused for a later mission. The
Co-Investigator for the microscope, John Marshall, of the Carl Sagan Center at the SETI Institute, felt strongly that Phoenix needed the microscope to fully
understand the processes that have influenced the northern terrain, but there
was a funding crisis and MECA was going to be cancelled. Marshall needed
$250,000-and fast-to rescue the microscope. He cornered Scott Hubbard, then
Director of NASA Ames Research Center, the man who had signed off on the Scout
Program to begin with, and convinced him to find the money. In 48 hours, the
$250,000 had been scraped together and MECA was saved.
Phoenix's mission is to use a
robotic arm to dig through the protective top soil layer to the water ice below
and, ultimately, to bring both soil and water ice to the lander platform for
sophisticated scientific analysis. But, like most scientific endeavors, finding
what you are looking for is just the first step. Next you need to understand
how it, in this case, soil and the water mixed with it, got there and how it
has affected, and been affected by, its environment. The science team wants to
understand the origin of the soil. Was it brought by wind? By water? Affected
by water and ice? What processes has it gone through? No single instrument can
tell the whole story.
Think
of the investigation as a several step process. MARDI, the Mars Descent Imager,
will take pictures on the way to the Martian surface to give context. Are we
landing on bedrock? Is this soil volcanic, blasted here by an ancient eruption?
After landing, the solar arrays will be deployed, the MARDI images will be sent
and the host of instruments will start whirring to action. Then, a Robotic Arm
will reach out and deliver samples to either the TEGA (Thermal and Evolved Gas
Analyzer) or MECA instruments. Now comes the turn for John Marshall's
microscope. MECA consists of two microscopes, an optical microscope and an
atomic force microscope (AFM) sharing some common parts, and complimenting one
another. The optical microscope looks down to the level of silt and dust, and
the AFM looks further still, down to superfine dust.
Another
Phoenix instrument, TEGA, a combination high-temperature furnace and mass
spectrometer instrument, will carry the story even further by looking at the
chemistry of the icy soil to determine ratios of various isotopes of hydrogen,
oxygen, carbon, and nitrogen, providing clues to origin of the volatile
molecules, and possibly, biological processes that occurred in the past.
NASA's
Phoenix Scout isn't a bit of fantasy, but it has, metaphorically, at least,
risen from the ashes and its full suite of instruments was saved by a hair's
breadth. Skill and passion, patience and hard work, lessons learned, care and
expertise will all come together very soon to make something that is its own
kind of magic – a space exploration mission.
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