On 12th April 1981 a revolutionary new spacecraft blasted off from Florida on her maiden flight. NASA’s Space Shuttle Columbia was the most advanced flying machine ever built – the high watermark of post-war aviation development. Never before had a crew been so well prepared for their mission. Yet less than an hour after Young and Crippen’s spectacular departure from the Cape it was clear that all was not well. Tiles designed to protect Columbia from the blowtorch burn of re-entry were missing from the heatshield. If the damage to their ship was too great the astronauts would be unable to return safely. But neither they nor mission control possessed any way of knowing. Instead, NASA turned to the National Reconnaissance Office, a spy agency hidden deep inside the Pentagon whose very existence was classified. To help, the NRO would attempt something that had never been done before.