Smooth surface. The landing site chosen for the Polar Lander (right) is much flatter than the area where Pathfinder touched down in 1997 (left).

Smooth Spot Found for Mars Polar Lander

The view is nothing special at the landing site of the Mars Polar Lander, but scientists hope the geology will make up for it. Exactly 100 days from today, on Friday 3 December, NASA's second Mars lander in less than 30 months will touch down some 800 kilometers from the south pole of the red planet, on a craterless, icy plateau that's flatter than Kansas. Project scientist Richard Zurek of NASA's Jet Propulsion Laboratory announced the landing site--at 76 degrees south latitude and 195 degrees west longitude--today at a press conference in Washington, D.C.

NASA selected the spot using high-resolution images and laser measurements from NASA's Mars Global Surveyor, which currently orbits the planet. They showed that the site is very smooth, making it a safe area to land. (Unlike the Pathfinder, whose fall was cushioned by airbags, the Polar Lander will land on a tripod.) "If we only had [1976] Viking images to rely on," says Zurek, "we would probably have chosen another area." The Global Surveyor data also showed that the site should afford a good look at the enigmatic layered terrain at the Martian pole. The lander will look for ice and study the composition of the surface to learn whether the layers have been created by cyclic deposition or cyclic erosion, which in turn should help gauge past changes in the Martian climate.

Launched last January, the Polar Lander will arrive late in the Martian spring and will experience a midnight sun. But there won't be much to see. At the site, "the total variation in altitude is less than 40 meters over an area of 200 kilometers," says Zurek. "Slopes are generally less than two degrees." As a result, the stereoscopic panorama photos that the spacecraft will send home will be much less spectacular than the Mars Pathfinder images that held the world captivated for days in July 1997.

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