It’s a subject near and dear to NASA Administrator Dan Goldin’s heart. When will the space agency ever send a man to Mars? “First of all, we’re going to put a human on Mars, not a ‘man’ ” he told a questioner at Monday’s budget briefing at NASA headquarters. “This is a decision that’s not made by the president of the United States,” Goldin said. “This is a decision that’s made by the American people.”