Artist's impression of Mars Phoenix shortly after landing on the Red Planet.
Phoenix Mars mission ready for landing
15 May 2008
The Phoenix Mars Lander is preparing to end its long journey and begin a three-month mission to taste and sniff handfuls of martian soil and buried ice. The lander is scheduled to touch down on the Red Planet on May 26.
Phoenix, a mission led for NASA by The University of Arizona (UA), will enter the top of the martian atmosphere at almost 121,000 kph. In seven minutes, the spacecraft must complete a challenging sequence of events to slow to about 8 kph before its three legs reach the ground. Confirmation of the landing could come as early as 9:53am Sydney time.
'Putting a spacecraft safely on Mars is hard and risky,' said Ed Weiler, associate administrator for NASA's Science Mission Directorate at NASA Headquarters in Washington. 'Internationally, fewer than half the attempts have succeeded.'
Rocks large enough to spoil the landing or prevent opening of the solar panels present the biggest known risk. However, images from the High Resolution Imaging Science Experiment, known as HiRISE, camera on NASA's Mars Reconnaissance Orbiter, detailed enough to show individual rocks smaller than the lander, have helped lessen that risk. The HiRISE team is based at UA, led by principal investigator Alfred McEwen of the Lunar and Planetary Laboratory.
The landing site for Mars Phoenix, as imaged by the HiRISE camera aboard the Mars Reconnaissance Orbiter spacecraft.
'We have blanketed nearly the entire landing area with HiRISE images,' said Ray Arvidson of Washington University in St. Louis, chairman of the Phoenix landing-site working group. '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 uses much of the hardware from a spacecraft built for a 2001 launch that was cancelled in response to the loss of a similar Mars spacecraft during landing in 1999. Phoenix principal investigator Peter Smith of the UA's Lunar and Planetary Laboratory proposed the mission in 2002 because he saw the unused spacecraft as a resource for pursuing a new science opportunity.
Smith proposed the Phoenix Mission after UA professor William V. Boynton's Gamma Ray Spectrometer on NASA's Mars Odyssey orbiter discovered earlier in 2002 that plentiful water ice lies just beneath the surface throughout much of high-latitude Mars.
NASA chose Smith's Phoenix proposal over 24 other proposals to become the first endeavour in the Mars Scout program of competitively selected missions. With that selection, UA became the first public university to lead a mission to Mars.
Phoenix will land farther north on Mars than any previous mission.
'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 percent of the martian surface, is habitable,' Smith said.
Mars Phoenix will use its 2.4-metre-long arm to scoop up soil samples.
The solar-powered robotic lander will manipulate a 2.4-metre-long arm to scoop up samples of underground ice and soil lying above the ice. Onboard laboratory instruments will analyse 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 favourable 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.
Adapted from information issued by NASA.
