Virtually traveling Mars

A new feature on NASA's Web site uses 3-D software that lets scientists take virtual trips on Mars.

The software — called Viz — produces 3-D views of Mars from two-dimensional stereo images sent to Earth by the two Mars exploration rovers. Scientists wear stereo glasses that display 3-D images of the planet and plan paths for the vehicles by virtually placing them on Mars.

"Viz gives scientists on Earth an excellent understanding of Martian topography, and from that, researchers can suggest possible ways that Mars changed over eons," Laurence Edwards, Viz project leader at NASA Ames Research Center, said in a statement.

Using Viz, researchers can understand Martian sites being studied and the rover's situation in those locations, Edwards said. NASA officials announced the availability of the 3-D feature on the site Oct. 25.

Using Viz, scientists make mouse clicks to measure rock surface areas and distances between rocks. The software reveals topographical information by allowing scientists to pour virtual liquid into depressions. This helps researchers develop theories about how water and wind erosion or volcanic activity on Mars may have altered the planet.

Viz can predict when and where the sun will cast shadows on the rover and its surroundings. This forecast helps scientists plan when to take pictures to obtain the best data. The software also can pan and tilt a virtual Mars rover camera to preview what the resulting image will be like even before the rover is in position.

Differences in the left and right images produced by the software allow scientists to calculate the 3-D location of points in the rover images, similar to how binocular vision works. An LCD shutter glass mechanism alternatively presents left and right images to each eye at a high rate, creating the 3-D effect for mission scientists, rover engineers and maybe the general public some day.

Unlike 3-D films, Viz projects interactive simulation. Similar software dates back to the mid 1990s, when MarsMap software aided scientists during the Mars Pathfinder 1997 mission.