NASA - National Aeronautics and Space Administration

Launch of the Mars Exploration Rover Opportunity aboard a Boeing Delta II heavy launch vehicle has been rescheduled for no earlier than Sunday, July 6 -- with two launch opportunities available at 10:43 p.m. and 11:26 p.m. EDT. Previously, the launch had been delayed due to problems with the cork insulation on the Delta II launch vehicle's first stage

Opportunity had two launch opportunities last weekend. Winds threatened the first opportunity, which had to be foregone when a boat came too close to the coastal launch site. The second launch attempt was cancelled when it became clear high-altitude winds were too strong.

Opportunity and the rover Spirit are part of NASA's Mars Exploration Program, a long-term effort of robotic exploration of the red planet. The program seeks to take advantage of each launch opportunity to go to Mars, which comes around every 26 months as the planets move around the Sun. The two rovers will land at separate sites on Mars in January 2004.

Primary among the mission's scientific goals is to search for and characterize a wide range of rocks and soils that hold clues to past water activity on Mars. The spacecraft will be targeted to sites that appear to have been affected by liquid water in the past.

After the airbag-protected landing craft settle onto the surface and open, the rovers will roll out to take panoramic images. These will give scientists the information they need to select promising geological targets that will tell part of the story of water in Mars' past. Then, the rovers will drive to those locations to perform on-site scientific investigations over the course of their 90-day mission.

The rover is designed to drive up to 40 meters (about 44 yards) in a single day, for a total of up to one 1 kilometer total (about three-quarters of a mile).

Moving from place to place, the rovers will perform on-site geological investigations. Each rover is sort of the mechanical equivalent of a geologist walking the surface of Mars. The mast-mounted cameras are mounted 1.5 meters(5 feet) high and will provide 360-degree, stereoscopic, humanlike views of the terrain. The robotic arm will be capable of movement in much the same way as a human arm with an elbow and wrist, and will place instruments directly up against rock and soil targets of interest.

In the mechanical "fist" of the arm is a microscopic camera that will serve the same purpose as a geologist's handheld magnifying lens. The Rock Abrasion Tool serves the purpose of a geologist's rock hammer to expose the insides of rocks.

+ Mars Exploration Program Web site

+ Kennedy Space Center Launch Web site