PASADENA, Calif. (AP) _ NASA's Mars Polar Lander is in excellent shape and on track for a safe landing Friday, mission controllers said Tuesday after fine-tuning the spacecraft's path toward the Red Planet. The $165 million probe's thrusters were fired for 12.6 seconds to keep it on course for landing near the planet's south pole, said Sam Thurman, the spacecraft's flight operations manager at NASA's Jet Propulsion Laboratory. The probe has traveled nearly 470 million miles since its Jan. 3 launch. It is expected to spend 90 days searching for water and studying Mars' climate history. Mission controllers say they are confident the lander will arrive safely given all the reviews and double-checking that occurred after the Sept. 23 loss of its companion spacecraft, the Mars Climate Orbiter. The orbiter, which disappeared just as it was starting to circle the Red Planet, arrived at too low an altitude to survive, the result of a navigation error caused by not converting measurements to metric units.