24-05-2008 Phoenix Lander (Article 138)

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Simon Kenny
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24-05-2008 Phoenix Lander (Article 138)

Post by Simon Kenny » Wed Dec 31, 2008 10:50 am

Phoenix: from the ashes of failure. (Article 138)

Following the premature failure of the Polar Lander mission to the South Polar Regions of Mars in December 1999, NASA launched a similar craft in August 2007. Scheduled to arrive on May 25th, 2008, it will attempt a landing near Mars’ North polar region, which will then be tilted towards the Sun, providing better lighting conditions and more solar power for the instruments.

Unlike recent missions which used inflated balloons to break the landings, Phoenix reverts to the older methods used for the Viking landers in the 1970s. On entering Mars’ atmosphere, Phoenix will be protected from burning up by an aeroshell, which will be jettisoned later and a parachute then deployed to slow its descent further. Finally, six rockets underneath the craft will slow it to a soft landing on the arctic region of Mars.

Unlike recent surface missions, Phoenix will be fixed to the spot where it lands. This is partly due the need to develop the landing craft cheaply and quickly from existing components. Also, it was thought its landing area had little structural variation, making a mobile platform unnecessary. The stationary platform is also lighter and enabled designers to pack more experiments.

The most complex suite of experiments is the Microscopy, Electrochemistry, and Conductivity Analyser (MECA). This performs a series of chemical and electrical tests on Martian soil deposited by the craft’s mechanical scoop. It also has microscopes to examine the soil down to molecular level. MECA will provide a detailed chemical profile of the soil and its components, determining its capacity to support, or destroy living organisms. The robotic arm is designed to dig a half metre into the soil or ice. Attached to it is a camera for taking close up pictures of the soil inside and around the scoop, as well as panoramic pictures. It will supplement the work of the main camera, an advanced stereo imager designed to take detailed images of the surrounding terrain and atmosphere.

The Thermal and Evolved Gas Analyser (TEGA) is another complex experiment which heats soil samples to detect and analyse the ice and organic compounds found within them.

Phoenix is also equipped with a meteorological station to examine weather patterns throughout the life of the mission. It has sensors to measure temperature, atmospheric pressure, wind speed and direction. It also has a Laser Imaging Detection and Ranging instrument (LIDAR). This uses laser light to measure the opacity of the atmosphere by counting the airborne dust particles at various levels above the craft. From this a detailed profile can be derived of air movements, dust, cloud and fog formations in the Martian Arctic regions.

Phoenix has a circular, table like platform supporting the experiments, flanked by two circular arrays of photo-voltaic cells that will use the slanted sunshine of the Mars high Arctic to replenish its batteries, so essential for the success of the three month mission.

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