As the final moments ticked away before the Space Shuttle Challenger's launch on January 28, 1986, millions of viewers were transfixed by their television screens. A rocket launch was already a significant occasion, but this particular mission carried an extraordinary passenger, Christa McAuiffe. The 37-year-old was set to become the first teacher in space having been chosen from over 11,000 candidates for the NASA programme - yet merely 73 seconds into its journey, Challenger burst into a