May 26, 2008 NASA has announced the successful touchdown of the Phoenix spacecraft on arctic plains in the north of the Red Planet. The completion of the 10 month journey was confirmed with the detection of a radio signal from Phoenix (a signal which takes more than 15 minutes to reach Earth) indicating that it had reached the Martian surface. The spacecraft reached speeds of approximately 12,000 mph before entering the top of the planet's atmosphere and beginning its decent towards a soft touchdown on its three-legs made possible by parachute deployment and finally, the use of controlled thrusters.

Launched on August 4, 2007, Phoenix is the sixth lander to touch down on Mars with only five of the 11 previous international attempts having succeeded including the first successful landing of the Viking program in 1976.

Phoenix landed at 4:53 p.m. Pacific Time (7:53 Eastern Time), May 25, 2008, in an arctic region called Vastitas Borealis, at 68 degrees north latitude, 234 degrees east longitude.

The landing site was chosen because of the existence of subsurface water ice detected by the Mars Odyssey Orbiter in 2002.

Overall the stationary lander has three goals on Mars: to study the history of water in all its phases; to determine if the Martian arctic soil could support life; and to study Martian weather from a polar perspective. The results from the craft’s 92 (Earth) day tenure are hoped to provide scientists with information on the history of the planet, and the processes of climate change.

The Phoenix is equipped with a 2.35-meter aluminum and titanium arm to break through the concrete-like Martian ice and gather samples. The arm moves like a back-hoe, using up-and-down, side-to-side, back-and-forth, and rotation, to dig up to 20-inches below the surface level. After collecting the samples, the arm will transport the material to the lander’s laboratory, where it will heat the material in tiny ovens to examine the vapors, measure the electrical and thermal conductivity of soil particles, and immerse it in water to analyze the dissolution products. While the craft is unable to detect present or past life, it can identify organic compounds like carbon and hydrogen – not a smoking gun for life, but certainly an interesting discovery.

Dr. Peter H. Smith, head of the Phoenix mission, states, “Phoenix has the scientific capability to change our thinking about the origins of life on other worlds. Even though the northern plains are thought to be too cold now for water to exist as a liquid, periodic variations in the Martian orbit allow a warmer climate to develop every 50,000 years. During these periods the ice can melt, dormant organisms could come back to life, (if there are indeed any), and evolution can proceed. Our mission will verify whether the northern plains are indeed a last viable habitat on Mars."

The Robotic Arm Camera is able to take full-color pictures of the area and the samples, and has a resolution of 23 microns per pixel at the closest focus, far greater than the cameras on the Spirit and Opportunity rovers. The primary camera on the lander is the Surface Stereo Imager, which will measure the atmospheric distortion of the Martian atmosphere. The SSI contains two cameras, providing three-dimensional information through 12 possible filters, including infrared frequencies. The cameras have roughly the same resolution as the human eye, though with a smaller field of view.

Phoenix is the first spacecraft launched as part of the NASA Mars Scout Program, which aims to mount a series of small, low-cost missions to Mars, based on select proposals from the scientific community. The Phoenix mission, which required a total US investment of $420 million, is a partnership of universities in the US, Canada, Switzerland, Denmark, Germany and the UK, NASA, the Canadian Space Agency, and the aerospace industry.

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