NASA’s Phoenix Mars Lander has left for the planet’s North Pole. It carries with it the most ambitious laboratory ever to be flown to a planet.

It was launched by the same Delta 7925 rocket,  used for Mars Pathfinder in 1996 and the Mars Exploration Rovers (Spirit and Opportunity) in 2003. 

Nine and a half months later it will touch down on water ice and solid carbon dioxide at almost 70 degrees north latitude. On Earth, Alaska, Greenland and Siberia share the same latitude.

n the past no successful mission has landed so close to a Martian pole.  Viking 1 (1976) and the Mars Pathfinder (1997), had descended to the Martian equivalent of  the latitude of Mumbai.

The two spots where Spirit and Opportunity had landed in 2004, and in the vicinity of which they are still roving  for more than three years now, are both close to the equator.

Incidentally, Viking 2 ( 1976), which  had touched  down ata latitude of  about  42 degrees North remains  on records as  the spacecraft  that had landed closest to a Martian pole.

Why has NASA chosen such an eerie landing site?

The orbiting Mars Odyssey spacecraft had indicated that the poles are water rich. In particular the Phoenix landing site has been estimated to have as much as 80 percent by volume of water ice within a depth of only 20 inches.

So  when  Phoenix touches down ,  next year  when it is  summer at the North pole of Mars ,  it will  readily find  ice  within easy reach of its  almost 8-ft. long robotic arm. The assignment for which it has come from the Earth will start forthwith.   No spacecraft has ever explored any of the Martian poles before.

Besides the robotic arm the other instruments include a descent imager, panoramic camera, thermal evolved gas analyzer, mass spectrometer, optical and atomic force microscopes, electrical and thermal sensors, a wet chemistry laboratory and a suite of meteorological instruments.

Also among these are eight “bake and sniff” sampling ovens and four cells where water from Earth will be stirred with Martian soil for analysis.

These   are all robotic marvels having dozens of doors, valves and other moving parts. They will help in finding if hitherto unknown organic carbon building-blocks of life are there.  Phoenix, a stationery lander,   is not designed to detect living organisms; however, its atomic force microscope will be able to see objects as small as 100 microns, which is the size of bacteria.

 Further, it will test samples of ice/ water for their acidity and potential to hold food sources for any life that might be there. 

Landing sans  air bags
The Phoenix lander is almost as heavy as Spirit or Opportunity.  However, as it is much larger it will not be able to land on airbags as Mars Pathfinder had done in 1997 or as the rovers did in 2004.  Instead it will make a ‘self-powered’ descent like the two Viking spaceships did more than three decades ago.  

Immediately after reaching the Red Planet the two big solar arrays that Phoenix has will unfurl and in the Martian summer the three-month mission will commence.

After a week on Mars digging will start.  A month later at the end of June, 2008, around the summer solstice the highest levels of solar power will occur. Then with the coming of autumn the Sun will sink lower and lower on the horizon, starving the lander of power.  It may operate for another two months or so.

But with advancing ice, Phoenix will gradually become entombed in several feet of solid carbon dioxide. As it has not been designed to survive this state the mission will be over.  

Why Phoenix?
The mission owes its name to the mythical bird which was reborn from its own ashes. This venture too  has originated from  the ashes of two failed  missions: the Mars Polar Lander  which was lost on Mars in 1999 and the Mars Surveyor program lander which was cancelled and stored  in a warehouse  from  2000  until it was needed by engineers designing Phoenix. 

 After much effort human beings first reached our planet’s north pole in 1909.  It is mind boggling to think that in the short span of less than a hundred years a space ship has been designed to survey the north pole of a planet that astronomers have calculated will be 171 million miles away by the time the instruments chosen for its initial exploration reach. 

The writer is a member of the landing site characterization team for Phoenix and Science team for Mars Exploration Rover Mission.