Phoenix Mars Lander looks for life using photonics

May 22, 2008-->NASA's Phoenix space probe will land on Mars May 25, and use a variety of photonics and other technologies to look for signs of life.

May 22, 2008-- NASA's Phoenix Mars Lander is preparing to end its 422-million mile journey and begin a three-month mission to look for signs of life in the Martian soil and buried ice. The lander, which was launched last August, is scheduled to touch down on the Red Planet May 25.

Phoenix uses some of the most sophisticated and advanced technology ever sent to Mars. A robust robotic arm built by JPL will dig through the soil to the water ice layer underneath, to deliver soil and ice samples to the mission's experiments. On the deck, miniature ovens and a mass spectrometer, built by the University of Arizona and University of Texas-Dallas, will provide chemical analysis of trace matter. A chemistry lab-in-a-box, assembled by JPL, will characterize the soil and ice chemistry. Imaging systems, designed by the University of Arizona, the Max Planck Institute (Germany), and Malin Space Science Systems (including an atomic force microscope provided by the University of Neuchatel, Switzerland), will provide an unprecedented view of Mars—spanning 12 powers of 10 in scale. The Canadian Space Agency delivered a meteorological station, marking the first significant involvement of Canada in a mission to Mars.

Phoenix will enter the uppermost the Martian atmosphere at nearly 13,000 mph. Within seven minutes, the spacecraft will execute a challenging sequence of events to slow to approxmiately 5 mph before it touches down. Confirmation of the landing could come as early as 7:53 p.m. EDT, 4:53 p.m. MST.

Historically, landing a probe on Mars hasn't been a simple matter. Internationally, fewer than half the attempts have succeeded. Rocks large enough to damage the spacecraft upon landing or prevent opening of the solar panels present the biggest obstacle. However, images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter, are detailed enough to show that individual rocks at the landing site are smaller than the lander, which helps lessen that risk.

Ray Arvidson of Washington University (St. Louis, MO), chairman of the Phoenix landing-site working group, said, "This is one of the least rocky areas on all of Mars and we are confident that rocks will not detrimentally impact the ability of Phoenix to land safely."

Phoenix will be carrying two special tools to enable scientists to accurately image the Red Planet's true colors. Two hockey-puck sized color-calibration targets covered with color chips will be captured in any images taken by the probe's cameras. The targets, designed by University of Central Florida (UCF) physics and astronomy professor Dan Britt and two students, will allow scientists to compare the colors in each photo and determine the actual hues.

Knowing the true colors allows spectroscopists such as Britt to determine the composition of the planet's soil. The colors are one reason NASA says that liquid water once existed on Mars, and they help geologists analyze layers of rock deposited over thousands of years.

Previous color chips became encrusted with dust from the gusty, dusty atmosphere on Mars, obscuring the true color. So the calibration targets on the Phoenix have built-in magnets to repel the iron-filled dust. Each magnet is about 100 times stronger than a refrigerator magnet and should keep the targets clean while the lander samples soils in the Martian arctic region. While Britt created the color chips, the targets and magnets were designed by scientists from the University of Copenhagen in Denmark.

Britt began creating the color chips for Phoenix about three years ago in his UCF lab. Comprised of rubbery silicon and paint pigments, the color chips were embedded in an aluminum casting and tested under extreme conditions--intense ultraviolet light and depressurization--before launch last year.

Several of the Phoenix lander's color targets are coated by a new metal-infused coating created by Britt and UF chemistry professor Randolph S. Duran. The coating also should help keep away the dust, Britt says.

In 2002, NASA's Mars Odyssey orbiter discovered that plentiful water ice lies just beneath the surface throughout much of high-latitude Mars. NASA chose the Phoenix proposal over 24 other proposals to become the first endeavor in the Mars Scout program of competitively selected missions. Phoenix will land farther north on Mars than any previous mission. THe Phoenix mission goals are to answer three questions: (1) can the Martian arctic support life, (2) what is the history of water at the landing site, and (3) how is the Martian climate affected by polar dynamics?

"The Phoenix mission not only studies the northern permafrost region, but takes the next step in Mars exploration by determining whether this region, which may encompass as much as 25% of the Martian surface, is habitable," said Peter Smith, Phoenix principal investigator at the University of Arizona, Tucson.

The solar-powered robotic lander will manipulate a 7.7-foot arm to scoop up samples of underground ice and soil lying above the ice. Onboard spectroscopic and chemical laboratory instruments will analyze the samples. Cameras and a Canadian-supplied weather station will supply other information about the site's environment.

One research goal is to assess whether conditions at the site ever have been favorable for microbial life. The composition and texture of soil above the ice could give clues to whether the ice ever melts in response to long-term climate cycles. Another important question is whether the scooped-up samples contain carbon-based chemicals that are potential building blocks and food for life.

The Phoenix mission is led by Smith with project management at JPL. The development partnership is with Lockheed Martin, Denver. International contributions are from the Canadian Space Agency; the University of Neuchatel, Switzerland; the universities of Copenhagen and Aarhus, Denmark; the Max Planck Institute, Germany; and the Finnish Meteorological Institute.

For a related Laser Focus World articles, please see: "HiRISE camera details dynamic wind action on Mars".

For more information on the Mars Phoenix, visit JPL's Mars Phoenix Mission homepage.

--V.C.

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