AS-203 blasts off from the LC-37B launchpad.
Fifty Years Ago, on July 5, 1966 NASA tested a major component of the Apollo/Saturn system. An unmanned Saturn 1b rocket lifted off from Cape Kennedy with a Saturn IVB stage that needed testing and certification.
AS-203 sitting on the Saturn 1b pad modification pad.
The rocket lifted off and the flight went well, throwing the Saturn IVB stage into an orbit 100 miles above the surface. Engineers conducted tests on the fuel movement, useage, and storage. They also conducted tests alternating pressurizing and depressurizing the stage. During one of those tests, contact was lost and radar at the Trinidad Tracking Station detected the stage now in multiple pieces. NASA finally concluded that the propellants in either of the two tanks had exploded. Despite the loss, NASA considered it a success, as all systems were tested and had functioned.