NASA has big plans for the 2020s, from powerful new space telescopes to a hunt for alien life on a moon of Saturn. Here's the timeline.

· NASA has big plans for this new decade: The agency is working to send humans back to the moon and search for life near Saturn.
· NASA's 10-year plan also includes missions to probe the metal core of a dead planet, photograph the Big Bang, and scan for aliens in a hidden ocean on Jupiter's moon Europa.
· Here's what to...