A European could step out onto the surface of Mars within three decades, under European Space Agency (ESA) plans spelled out on Tuesday. The plans are more precise than the broad U.S. goals of sending a man back to the moon by 2020 and to Mars by 2030, revealed last month by President Bush. “We think it is technically feasible to have a manned mission to the moon between 2020 and 2025 and then to Mars between 2030 and 2035,” said Franco Ongaro, project manager of the ESA’s fledgling Aurora space exploration program.