[meteorite-list] NASA to Begin Digging Mission on Northern Pole of Mars (Phoenix)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 31 Jul 2007 17:20:04 -0700 (PDT)
Message-ID: <200708010020.RAA26609_at_zagami.jpl.nasa.gov>

NASA to Begin Digging Mission on Northern Pole of Mars
By WARREN E. LEARY
The New York Times
July 30, 2007

WASHINGTON, July 30 - NASA is about to launch a scientific laboratory to
Mars that will be the first spacecraft to land in the northern polar region
of the planet and dig for evidence of water or other conditions that could
support some form of life.


The spacecraft, Mars Phoenix Lander, is set to launch from Cape Canaveral,
Fla., on a Delta II rocket during a three-week window that opens Friday. If
the 770-pound lander touches down safely after its 10-month journey, it
will spend three months or longer probing the ground and monitoring the
weather above.

Unlike rover missions that explore large areas, Phoenix is to stay on one
spot in the permafrost region of the Martian arctic and use a mechanical
arm to explore the area in detail. "This is a vertical mission," said Peter H.
Smith of the University of Arizona, the mission's principal scientist. "We
are going to dig down and not explore horizontally."

The target area rests at latitudes equivalent on Earth to Northern Alaska,
Siberia or Greenland, Mr. Smith said. It is covered with polar ice in the
winter, but Phoenix is to arrive in the summer when the ground is mostly
clear.

After landing, the robot spacecraft will unfurl a pair of circular solar
power arrays that give it a width of 18 feet. It will deploy a pair of
stereoscopic color cameras on a mast that extends 7 feet above the surface
to record panoramic views, and extend a 4-foot mast bearing temperature
sensors from an onboard weather station supplied by the Canadian Space
Agency.

The weather station, designed to operate even after the craft's primary
digging mission is completed, is to track daily and seasonal changes in
temperature, atmospheric pressure and wind speed and direction. In
addition, a pulsing laser will fire into the atmosphere to measure the
size and altitude of dust and ice particles in the vicinity.

With a 7.7-foot-long hinged arm that operates like a backhoe, the craft is
to dig a series of trenches more than 20 inches into the ground with a
movable metal scoop that has sharp prongs and serrated blades on the end.
At full range, the arm can reach eight square yards of surface area near
the lander, Mr. Smith said.

Guided by a camera on the end of the scoop, scientists will select soil and
ice samples for detailed study by instruments on the lander. For one
experiment, the Thermal and Evolved Gas Analyzer, samples will be dropped
into a hopper to feed eight single-use ovens the size of an ink cartridge
in a ballpoint pen. The sample will be slowly heated to 1,800 degrees
Fahrenheit to study the transition from solid to liquid to gas, and the
vapors analyzed by a mass spectrometer to measure the mass and composition
of specific molecules.

Four other samples are to be examined in a miniature wet chemistry
laboratory, where they will be stirred into a prewarmed solution and mixed
with chemicals to tease out certain constituents, such as carbonates,
sulfates and soil oxidants. Such components could either encourage or deter
the formation of life if liquid water were available at times, scientists
said.

This laboratory also contains two microscopes to examine the fine structure
of soil and ice samples, revealing features as small as 1/1,000th the width
of a human hair that could be evidence of past liquid water on the planet.

Phoenix draws its name from the mythical bird that rose from its ashes
because it is made of parts of two earlier efforts to explore Mars. "It's
really getting a second chance, as its name implies," said Douglas
McCuistion, director of the Mars Exploration Program at NASA. "It is mainly
refurbished hardware."

The spacecraft is made of the supporting structure and some instruments
from the 2001 Mars Surveyor lander, which never flew because of cost overruns,
and several backup instruments from the unsuccessful Mars Polar Lander in
1999.

Mr. McCuistion estimated the project would cost $420 million, including $90
million for the launch rocket. He said the amount was $25 million to $30
million above initial estimates because the program decided to do more
tests and simulations to help assure mission success.

Recent spacecraft like the rovers Spirit and Opportunity have landed on
Mars encased in airbags to cushion their fall and bounce around obstacles.
Phoenix Lander is too heavy for the airbag approach so it will make a fiery
entry into Mars's atmosphere protected by a heat shield before being slowed
by a parachute and eventually making a soft landing with the help of
pulsing retro rockets.

Mr. McCuistion noted that the success rate for landing spacecraft on Mars
was under 50 percent, and that there was added risk in attempting a soft
landing.

While Phoenix is to operate during the Martian summer, scientists hope the
spacecraft survives dwindling sunlight and power to see approaching winter
cover the area with ice. "I'd be thrilled if we could last long enough to
see ice form around the spacecraft," Mr. Smith said.

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Received on Tue 31 Jul 2007 08:20:04 PM PDT