When NASA sent astronauts to the moon in the 1960s and 1970s the agency excluded women. Eventually, though, NASA opened the application process to a wider array of hopefuls. From a candidate pool of 8,000 six elite women were selected in 1978 - Sally Ride, Judy Resnik, Anna Fisher, Kathy Sullivan, Shannon Lucid, and Rhea Seddon. Together, the Six helped build the tools that made the space program run. One of the group, Judy Resnik, sacrificed her life when the Challenger exploded. Everyone knows of Sally Ride's history-making first space ride, but each of the Six would make their mark.