PASADENA, Calif. - The Spirit rover on Mars is prepared to roll and rock. Engineers have now turned the rover to exit its landing platform at Gusev Crater.

The overall health of the robot remains excellent. Spirit is ready to wheel onto Mars late tonight, into the early morning hours here at the Jet Propulsion Laboratory (JPL).

Spirit has been on Mars for 11 days.

Turn, turn, turn

"There's nothing left to do on the lander for Spirit. So tomorrow we're going to egress onto the surface of Mars," said Jennifer Trosper, JPL Mission Manager for the Mars Exploration Rover effort.

To several tunes, including Turn! Turn! Turn (To Everything There Is a Season) recorded by the Byrds, ground controllers have now positioned the rover "right on the spot" to wheel a short distance, some 10 feet (3 meters) to reach Mars' surface.

Once on Mars, Spirit's science gear is to begin the first set of up-close studies of nearby soil and rock.

Parting shots

Spirit will also take "parting shots" of its lander delivery system. "We want to give the engineers their dueto see their hardware for the last time," said JPL's Kevin Burke, Egress Mechanical Lead for the rover. Taken by a camera mounted on the back of Spirit, that image is eagerly awaited by engineers.

Burke said that controllers expect to have knowledge that Spirit has successfully wheeled off the lander between 1 a.m. to 2 a.m. Thursday morning, Pacific Standard Time.

Like a tourist on vacation loaded down with camera gear, Spirit is outfitted with an array of photographic gear. The rover's nine cameras - the largest number of cameras ever placed on Mars -- are in excellent working order, said Justin Maki, JPL Imaging Scientist for the rover.

This is 21st exploration through the Internet and having viewers watch from their living rooms, Maki said.

Look up, look down

While the rollout onto the surface of Mars is a historic moment, another scientific milestone is to occur.

Once Spirit is on the martian landscape, there is an overhead pass of NASA's Mars Odyssey. The robot will look up at the sky with science gear while Odyssey looks down with its science instruments to profile the patch of Mars where Spirit sits.

On Friday, the European Space Agency's Mars Express - a new arrival in Mars orbit - is to also train a suite of science instruments upon the site, while Spirit's sensors peer up into the martian sky.

Atmospheric monitoring

"It was serendipity," but also good planning, said Ray Arvidson, Deputy Principal Investigator for the Mars Rover program from Washington University in St. Louis, Missouri.

Having Spirit stare up while Mars Express looks down is being done on a scientist-to-scientist level, Arvidson said. Results of the experiment are to take several months to sort through.

One output from the experiment is to better characterize the amount and particle size of dust floating through the martian atmosphere, Arvidson explained.

Opportunity knocks at Mars

Meanwhile, with Spirit getting ready for full-service duties, the next rover is nearing the red planet.

It will dive toward Meridiani Planum, on the opposite side of Mars from where Spirit has landed.

Mars rover Opportunity is on track for touchdown on January 24, at 9:05 p.m. Pacific Standard Time.

This coming Friday, Opportunity will make a trajectory correction maneuver. If executed properly, further adjustments to the spacecraft' course will not be needed, said JPL's Peter Theisinger, Mars Exploration Rover project manager.

"It's easy to run these things when it goes well," Theisinger told SPACE.com