Digging deep: NASA's Phoenix lander will dig beneath the surface to take the first direct samples of Martian water ice.
Credit: NASA/JPL
SYDNEY: NASA's new Mars lander will travel to the Red Planet's far northern plains to break beneath its surface in the search of conditions favourable to life.
In a departure from previous missions – which have seen robotic vehicles explore the planet's hills and craters – the U.S. space agency's Phoenix Mars Lander will remain stationary where it lands and dig through the protective top soil layer to the water ice layer below.
The solar-powered probe will target this frigid polar region using a 2.3-metre robotic arm to bring both soil and ice to its main platform for analysis. A key fact it will determine is whether the ice might periodically melt enough to sustain a viable environment for microbes.
In addition, Phoenix will also check for the presence of organic compounds to evaluate whether the site has been an environment for microbial life in Mars' history.
"Voyage of exploration and discovery"
A rocket carrying Phoenix will blast off from Florida in August, beginning a journey expected to end several million miles later, on 25 May 2008, with a risky descent and landing.
"Following up on an Odyssey discovery in 2002, Phoenix will be the first mission to touch water in the form of ice and attempt to understand its affect on the soil mineralogy and chemistry," said Peter Smith, project leader at the University of Arizona, Tucson in the USA. "This is a voyage of exploration and discovery as so little is known about the polar regions."
The Mars Odyssey orbiter found evidence that large areas of the planet, including the target region, consist of subsurface water ice frozen with a metre or so of the planet's 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 Smith.
With its robotic arm, Phoenix will dig down to the icy layer and examine samples of the soil and the ice with its onboard instruments, including cameras and microscopes and tools never used before on Mars. The tools include: miniature ovens, a mass spectrometer (to check for volatile substances, such as water and carbon-based chemicals regarded as essential building blocks for life) and a chemistry-lab-in-a-box to further identify the nature of the soil.
A meteorology station, with a laser for monitoring water and dust in the atmosphere, will also provide information about atmospheric processes throughout the planned three-month mission, which takes place over the Martian spring and summer.
Touch-down
However, the initial priority for the mission is to safely touch down on the Vastitas Borealis, the Red Planet's northern arctic plains.
"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 in Pasadena, California. "Our team has been testing the system relentlessly since 2003 to identify and address whatever vulnerabilities may exist."
As used in previous Mars missions, the Phoenix will use a heat shield to slow its high-speed entry, before opening a supersonic parachute that will slash its speed to about 217 kph. The lander then separates from the parachute and fires pulsed descent rocket engines to slow to about 9 kph before landing on its three legs.
with Agençe France-Presse
