NASA’s next Mars mission will look beneath a frigid arctic landscape for conditions favorable to past or present life.
Instead of roving to hills or craters, NASA’s Phoenix Mars Lander will
claw down into the icy soil of the Red Planet’s northern plains. The
robot will investigate whether frozen water near the Martian surface
might periodically melt enough to sustain a livable environment for
microbes. To accomplish that and other key goals, Phoenix will carry
a set of advanced research tools never before used on Mars.
First, however, it must launch from Florida during a three-week period
beginning Aug. 3, then survive a risky descent and landing on Mars
next spring.
“Our ‘follow the water’ strategy for exploring Mars has yielded a
string of dramatic discoveries in recent years about the history of
water on a planet where similarities with Earth were much greater in
the past than they are today,” said Doug McCuistion, director of the
Mars Exploration Program at NASA Headquarters, Washington. “Phoenix
will complement our strategic exploration of Mars by being our first
attempt to actually touch and analyze Martian water — water in the
form of buried ice.”
NASA’s Mars Odyssey orbiter found evidence in 2002 to support theories
that large areas of Mars, including the arctic plains, have water ice
within an arm’s reach of the surface.
“Phoenix has been designed to examine the history of the ice by
measuring how liquid water has modified the chemistry and mineralogy
of the soil,” said Peter Smith, the Phoenix principal investigator at
the University of Arizona, Tucson.
“In addition, our instruments can assess whether this polar
environment is a habitable zone for primitive microbes. To complete
the scientific characterization of the site, Phoenix will monitor
polar weather and the interaction of the atmosphere with the
surface.”
With its flanking solar panels unfurled, the lander is about 18 feet
wide and 5 feet long. A robotic arm 7.7 feet long will dig to the icy
layer, which is expected to lie within a few inches of the surface. A
camera and conductivity probe on the arm will examine soil and any
ice there. The arm will lift samples to two instruments on the
lander’s deck. One will use heating to check for volatile substances,
such as water and carbon-based chemicals that are essential building
blocks for life. The other will analyze the chemistry of the soil.
A meteorology station, with a laser for assessing water and dust in
the atmosphere, will monitor weather throughout the planned
three-month mission during Martian spring and summer. The robot’s
toolkit also includes a mast-mounted stereo camera to survey the
landing site, a descent camera to see the site in broader context and
two microscopes.
For the final stage of landing, Phoenix is equipped with a pulsed
thruster method of deceleration. The system uses an ultra-lightweight
landing system that allows the spacecraft to carry a heavier
scientific payload. Like past Mars missions, Phoenix uses a heat
shield to slow its high-speed entry, followed by a supersonic
parachute that further reduces its speed to about 135 mph. The lander
then separates from the parachute and fires pulsed descent rocket
engines to slow to about 5.5 mph before landing on its three legs.
“Landing safely on Mars is difficult no matter what method you use,”
said Barry Goldstein, the project manager for Phoenix at NASA’s Jet
Propulsion Laboratory, Pasadena, Calif. “Our team has been testing
the system relentlessly since 2003 to identify and address whatever
vulnerabilities may exist.”
Researchers evaluating possible landing sites have used observations
from Mars orbiters to find the safest places where the mission’s
goals can be met. The leading candidate site is a broad valley with
few boulders at a latitude equivalent to northern Alaska.
Smith leads the Phoenix mission, with project management at the Jet
Propulsion Laboratory and the development partnership located at
Lockheed Martin, Denver. International contributions are provided by
the Canadian Space Agency, the University of Neuchatel, Switzerland,
the University of Copenhagen, Denmark, the Max Planck Institute,
Germany, and the Finnish Meteorological Institute.
Additional information on the Phoenix mission is available online at:
http://www.nasa.gov/phoenix
Additional information on NASA’s Mars program is available online at:
http://www.nasa.gov/mars