NASA - National Aeronautics and Space Administration

Thanks to NASA software that converts stereo still photos from Mars into 3-D images, scientists can now take virtual trips to 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 (MER). The system helps scientists plan by virtually placing them on Mars when they wear stereo glasses that display 3-D scenes of the red planet.

Viz software screen shot of the Mars Exploration Rover and Martian terrain. Click on image for publication size.

"Viz gives scientists on Earth an excellent understanding of martian topography, and from that researchers can suggest possible ways that Mars changed over eons," said Laurence Edwards, the Viz project lead at NASA Ames Research Center, located in California's Silicon Valley. The primary focus of Viz software is to provide a computerized martian 3-D scene, so researchers can understand the martian site under study and the rover's situation in that environment, according to Edwards.

The Viz software provides an extra margin of safety for the martian rovers that are operating anywhere from 35 million to 247 million miles (56 million to 399 million kilometers) away from Earth, depending upon the changing orbital positions of the two planets. Because of the huge distance between the planets, radio messages carrying images and other information sent from Mars at the speed of light, still take many minutes to reach Earth. During these delays, unforeseen problems could occur that might endanger the roving robots. So, mission planners on Earth must carefully think through each move Mars rovers make.

"The Viz 3-D stereo glasses really reveal the subtle and sometimes not-so-subtle variations in the terrain that you don't always pick up in a two-dimensional image," Edwards said.

Science-planning teams use Viz to measure rock surface areas and distances between rocks using computer mouse clicks. 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 software 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.

Viz software screen shot of the Martian terrain. Click on image for publication size.

Before the MER mission, a software ancestor of Viz, called MarsMap, helped Mars Pathfinder scientists virtually explore the red planet in 1997. That software provided vital help to the Pathfinder team when the Sojourner rover navigated to a large rock nicknamed 'Yogi.' "The overhang was obvious in the Ames 3-D virtual reality models but almost unnoticeable in the direct 2-D images traditionally used for navigation," said Michael Sims, a MER and Mars Pathfinder mission scientist from NASA Ames.

Another example of the power of the Viz using 3-D virtual reality took place during field tests on Earth in the year 2000, when scientists looking at two-dimensional photos noted what looked like a minor depression between their test rover and a rock they wanted to examine. However, scientists using 3-D stereo glasses and Viz immediately noticed that the low spot was dangerous. "In 3-D it was quite a sharp drop off," Edwards said.

Viz developers modified the latest version of the software to be adaptable to other NASA missions. Viz now allows two or more persons at different locations to communicate through Viz. The Viz team is planning to play a role in future Mars missions, which may well include rovers with more autonomy.

For more information visit: 3D Visualization Project

Credit: John Bluck (John.G.Bluck@nasa.gov), Ames Research Center