Over the past 50 years, American astronauts have been hailed as modern day heroes and explorers. Considering that only about 600 humans have ever been in space, it's quite a select group.

NASA astronaut and Commander of the 25th International Space Station Expedition, retired Colonel Douglas Wheelock appears on Tuesday's Smart Talk.

The space program may not get the attention from Americans that it did during the Apollo program or when space shuttles were exploring space every few months, but there often are discoveries being made and experiments being conducted that could impact our lives. For example, NASA's Kepler Space Telescope recently discovered more than 1,200 planets that could be similar to earth and have water content which could possibly sustain human life. What do findings like that mean for the future of NASA and space exploration?