Phoenix Mars Lander prepares to begin excavation
A successful landing and Mars's smooth surface sets optimum digging conditions
For the Phoenix Mars Lander, it’s time to get down to business.Skip to next paragraph
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After an historic, near-perfect landing on a broad, flat, pebble-strewn stretch of the Martian Arctic on May 25, the chemistry lab on legs is undergoing tests this week in preparation for its months-long hunt for water ice under the planet’s surface. The key question: Could this region, like its earthly counterparts, represent a suitable habitat for simple forms of life?
“This is a scientist’s dream,” said University of Arizona researcher Peter Smith, the project’s lead scientist, as he displayed initial photos from the lander of its environment at a post-landing briefing Sunday evening.
On Monday, the Phoenix team released a remarkable image of the lander, cocooned in its protective shell, hanging from its parachute during descent. The image was taken by the Mars Reconnaissance Orbiter's HiRise camera while the orbiter passed overhead to relay data from the lander.
One of the lander’s first tasks is to use its stereo camera, mounted on a mast, to take a 360-degree panorama of the site. The lander returned its first images of its landing site Sunday evening. The first 120-degree sweep may be available as early as Tuesday. The images will help mission planners build a 3-D model of the area that they will use to guide the robotic arm and its scoop to the excavation spots of choice.
Compared with dramatic scenes of the heavily sculpted Martian landscapes taken from orbit, the Phoenix landing site appears somewhat boring. But to mission scientists, boring is beautiful. A lack of boulders or cratered terrain significantly improved the likelihood of a safe landing. The surface – out to a featureless horizon – is broken into irregular polygon-shaped patches perhaps 15 feet across. The pattern looks very similar to those seen on the floors of the Dry Valleys of Antarctica or regions of northern Canada and Alaska.
On Earth's subsurface, ice contracts with frigid winter temperatures, opening cracks. In the Arctic, water can enter the cracks, freeze, and form ice wedges. In the much drier Antarctic, soil falls in, forming narrow furrows on the surface. As temperatures warm and the ice expands, the wedges halt further expansion, causing the patches to buckle in the middle – similar to the forms the lander has already experienced. The research team hopes the robotic arm and its digging scoop are within range of one of these areas between patches. If they were to find ice wedges, that would strongly imply at least the fleeting presence of liquid water during the melt season, Mr. Smith explains.