NASA successfully trimmed the course of a Mars-bound rover on Friday, putting the spacecraft on track for an early January arrival at the Red Planet. The first of as many as six trajectory correction maneuvers “worked perfectly,” mission manager Jim Erickson said from NASA’s Jet Propulsion Laboratory. The maneuver involved a series of rocket firings that increased the spacecraft’s velocity relative to the sun by nearly 32 mph, enough to fine-tune its path for a January 3, 2004 arrival.