TUCSON, Arizona (AP):

Fresh images sent back by NASA's Phoenix Mars Lander from the Martian northern polar region showed most of its science instruments were in good shape, mission scientists said.

The one snag on the lander occurred when the protective sheath around the trench-digging robotic arm failed to unwrap all the way after touchdown and now covers the arm's elbow joint.

Deputy project scientist Deborah Bass of NASA's Jet Propulsion Laboratory said scientists still planned to move the arm yesterday, but it could take an extra day to fully stretch it.

Since landing on Mars on Sunday, Phoenix has delighted scientists with the first-ever peek of the planet's unexplored northern latitudes.