When NASA sent astronauts to the moon in the 1960s and 1970s, the agency excluded women from the corps, arguing that only male military test pilots had the right stuff. But in 1978 six elite women took their place as astronauts. Drawing on her book The Six: The Untold Story of America's First Women Astronauts, journalist Loren Grush discusses how these brilliant and courageous women made history as part of America’s space program.