Except for its robotic arm, Opportunity finished unfolding from its landing position and was ready to travel the final 10 feet onto the surface of Mars, project manager Pete Theisinger told The Associated Press.
Scientists also adjusted the forward tilt of Opportunity's lander, pushing the platform downward so the tips of its exit ramp dug into the martian soil.
Engineers continued to make progress on Spirit, which has been sidelined for a week on the other side of the planet.
Engineers were prepared, if necessary, to wipe its flash memory clean of files that have stymied its software. The fix could restore Spirit to full health.
"I think it will be perfect again," Theisinger said.
Spirit began using its high-gain antenna again Wednesday to speed the transmission of data needed to debug the rover's problems. It also took its first picture in more than a week, with the images showing Spirit's robotic arm still poised as it had been then in front of a rock scientists had dubbed Adirondack.
"Everything's right where we left it," mission manager Mark Adler said.
Depending on the outcome, Spirit could return to its science work by late Sunday, Theisinger said.
While parked 6,600 miles away, Opportunity has been busy snapping its own surroundings, taking more than 500 pictures with its panoramic camera.
NASA released the first color photographs taken by Opportunity of fine layering in a rock outcropping roughly 10 yards from the parked rover. New black-and-white images show the formation in even higher resolution.
The outcropping rims a portion of the small crater in which Opportunity landed.
"Some of the detail you can see in here is pretty phenomenal," said camera scientist Jim Bell of Cornell University.
Scientists said patches visible in the layers appear to contain pebbles and other small stones that could indicate the rock formed in water. Drifting volcanic ash or wind-borne sediments also could have built up the thin layers.
Other images show impressions left in the fine-grained Martian soil when the air bag that swaddled the lander rolled to a stop after tracing a nearly full figure-eight pattern. The impressions reveal even the radial ribbing of the air bags, Bell said.
NASA sent the twin rovers on the $820 million mission to Mars to probe for geologic evidence of the past presence of water on what is now a largely dry, dusty planet.
NASA said it will name Opportunity's landing site in honor of the seven astronauts killed aboard the space shuttle Challenger in 1986. It previously named Spirit's landing site in memory of the Columbia shuttle crew killed a year ago.
By Andrew Bridges