Apollo 13 puts the astronauts to the ultimate test, returning a damaged spacecraft back safely to earth. A new lunar rover enables moonwalkers to explore further than ever. Apollo 17 sends man for the longest mission yet to the surface of the moon, but it's the last lunar mission for generations. Now, it's time for a new phase in the program. Converting an unused Saturn V rocket, NASA launches Skylab, America's first space station, letting astronauts live in space.