Phoenix Lander Takes Aim at Martian Arctic

NASA?s Mars-bound Phoenix spacecraft is gearing up for a landmark landing near the martian north pole this month to find out whether the region could have once supported microbial life.

Phoenix is on course for a planned May 25 touchdown in the martian arctic that, if successful, will mark the first powered landing on Mars since NASA?s hefty Viking 2 lander set down in 1976. But first, the probe is expected to fire its thrusters several times in the next few weeks to fine-tune its flight path.

?It?s scary how smooth it?s been,? said Barry Goldstein, Phoenix project manager at NASA?s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. ?The vehicle has just been behaving beautifully.?

The Phoenix lander tweaked its course in early April and is scheduled to fire its thrusters in three successive Saturday maneuvers beginning May 10. The spacecraft has flown so accurately that one of the maneuvers may not be necessary, Goldstein said.

Launched in August 2007, Phoenix is a stationary lander equipped with a trench-digging robotic arm to bite into the martian surface and scoop up samples of nearby soil and water ice. The probe?s top-mounted suite of ovens and wet chemistry instruments are designed to help determine whether its arctic plain landing site - a region similar in latitude to central Greenland or northern Alaska on Earth - could have once proven habitable for primitive life.

?We?re looking for all the ingredients for life,? Phoenix deputy principle investigator Deborah Bass of JPL told SPACE.com.

Phoenix also includes a martian atmosphere-monitoring station designed to provide daily weather updates during the probe?s planned three-month mission. Engineers at JPL will oversee the spacecraft?s initial Mars descent and landing before transferring operations to a control center at the University of Arizona, Tucson, for the remainder of the $420 million mission.

?This is an area of Mars that I have spent my career studying and I cannot wait to see those first images,? Bass said. ?To see that ice, what that frozen tundra is going to look like...whatever we see will be amazing because no one?s seen it before.?

Unlike the most recent probes to land on Mars - NASA?s twin rovers Spirit and Opportunity and the lost British lander Beagle 2 - Phoenix will not use airbags to cushion its arrival on the martian surface. Instead, it carries a set of rocket thrusters control its final descent, though its approach will mark the first powered landing attempt since NASA?s Mars Polar Lander crashed near the planet?s south pole in December 1999.

?I have always trumpeted the fact that we should be very guarded and very humble in our approach with what we?re trying to do, because it is so difficult,? Goldstein said, adding that engineers have identified and addressed as many of the risks as possible.

Phoenix?s science team, led by principle investigator Peter Smith at the University of Arizona, Tucson, has been eagerly preparing for the lander?s Mars arrival with a series of training simulations for landing day and mission operations. The most recent simulation, a dress rehearsal for Phoenix?s entry and descent through the martian atmosphere, was scheduled for Tuesday.

?At this point, we feel we?re in good shape and we want to do it. We?re ready,? Bass said. ?This team is itching to get its hands on this stuff?it?s show time.? 

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