The 2001 Mars Odyssey spacecraft is on target to orbit the Red Planet next week and erase the stigma of back-to-back mission failures, NASA officials said Thursday. “I expect nothing less than a bull’s-eye the night of Oct. 23” when the spacecraft fires its main thruster and slips into orbit, said David A. Spencer, Odyssey’s mission manager, at a press conference at the Jet Propulsion Laboratory.