Nearly six years after NASA's Mars Polar Lander (search) vanished during a landing attempt on the Red Planet, a scientist said he has spotted what appears to be wreckage of the spacecraft.

The observation came during a re-examination of grainy, black-and-white images taken by the orbiting Mars Global Surveyor (search), which searched for the probe with no success in 1999 and 2000.

"The observation of a single, small dot at the center of the disturbed location suggests that the vehicle remained more or less intact after its fall," wrote Michael Malin, president and chief scientist of San Diego-based Malin Space Science Systems (search), which operates the camera aboard Global Surveyor.

Malin makes his case in the July issue of Sky & Telescope magazine. A copy of his article was posted Thursday on the magazine's Web site.

Global Surveyor will take higher resolution images later this year in an attempt to confirm the missing lander's location.

"It looks intriguing," said Michael Meyer, the lead scientist for NASA's Mars Program. He said the images show just one possible location of the missing Polar Lander and more images are needed.

The $165 million Polar Lander was headed for touchdown near Mars' south pole on Dec. 3, 1999, when contact was lost. A NASA team concluded a rocket engine shut off prematurely, causing the spacecraft to plummet about 130 feet to almost certain destruction.

A re-examination of images of the surface of Mars taken after the Polar Lander's disappearance show a distinct white patch that could be a parachute. A few hundred meters away, scientists noted a dark area, possibly made from rocket blast marks, with a tiny white dot in the center that could be the lander.

The images pinpointing Polar Lander's possible location jibes with NASA's theory of the spacecraft's demise, Malin said.

Scientists at his firm decided to review the old Polar Lander images after last year's successful landings of the twin Mars rovers, Spirit and Opportunity. The rovers used a combination of rockets, parachutes and air bags to cushion their landing.

The Polar Lander used a similar system during its unsuccessful approach.

Its disappearance was a blow to NASA, which had lost the lander's $125 million sibling spacecraft, the Mars Climate Orbiter (search), three months earlier. That spacecraft apparently burned up as it was about to enter orbit.

The lander and orbiter were designed to study and analyze Mars' atmosphere and search for signs of frozen water beneath its south pole.