The NASA rover Spirit was ready today to make its final push to the rim of a big crater that scientists hope will provide a window into Mars’ geologic history. Spirit was close enough Wednesday to snap a panorama showing the rim on the opposite side of the crater, according to the Jet Propulsion Laboratory. Spirit was expected to finish its drive and be in position to peer inside the crater with a camera today. “We’re all waiting very anxiously to see what’s inside this crater,” said George Chen, the Spirit flight director.