Photos: A satellite spy in the skies

This graphic gives an overview of a Corona, with details on some of the systems. The tubular satellite -- an Agena spacecraft sent aloft by a Thor booster rocket -- included a pair of panorama cameras and something called a stellar-terrain camera. According to the NRO, the system took pictures while rotating, and the film -- yes, film -- had to be loaded into recovery vehicles for a return trip to Earth before anyone could see the orbital snapshots.

Credit: National Reconnaissance Office