 Scientists at the Centers for Disease Control and Prevention are reporting an outbreak of listeria. They say at least two people have died and dozens more have been hospitalized in 12 states. They linked the outbreak to meat sliced at deli counters. Pre-packaged deli meats do not appear to be involved. Fifty-five years ago today, Neil Armstrong and Buzz Aldrin landed on the moon. NPR's Nell Greenfield-Boyce reports on NASA's efforts to return astronauts to the lunar surface.