Saturday marks the 50th anniversary of Neil Armstrong becoming the first person to walk on the moon. It stands as a towering achievement in American history and a major scientific breakthrough for all humankind. But no one has been to the moon since U.S. astronauts were last there in 1972. In March, Vice President Mike Pence announced the goal of sending Americans back to the moon by 2024. NASA's plan involves returning to the lunar surface as well as establishing a space station in lunar orbit that may one day serve as a waystation for a mission to Mars. Advocates for returning to the moon see it as vital not only for human exploration, but also to maintain U.S. competitiveness with other nations, such as China. Skeptics of going back to the moon, however, says it’s too expensive and doubt whether the political will that powered lunar missions during the Cold War, still exists.