first flight in January 1961. Research and development (R/D) flights First flight In October 1961, the first Atlas-Centaur (Vehicle Flight-1: Atlas 104D and Centaur F-1) arrived at Cape Canaveral and was erected at the newly completed and specifically built LC-36A. Technical problems caused the vehicle to sit on the launch pad for seven months, the most serious being leakage of liquid hydrogen through the intermediate bulkhead separating the propellant tanks combined with numerous lesser maladies with the guidance and propulsion systems. Failure The vehicle was launched at 2:49 PM EST (18:49 GMT) on 8 May 1962, with the intention of performing a single burn with a partially fueled Centaur. Slightly under a minute into the launch, the Centaur stage ruptured and disintegrated, taking the Atlas with it in a matter of seconds. It was unclear what had caused the failure at first, as tracking camera footage merely showed a large white cloud enveloping the booster followed by the explosion of the entire launch vehicle. Initial assumptions were that Atlas had suffered a LOX tank failure, either from a pressurization problem, rupture of the tank from flying debris, or structural bending/aerodynamic issues caused by the unproven Atlas-Centaur combination, and indeed there had been several previous occurrences of these failure modes on Atlas launches. Scott Carpenter's Mercury flight was only days away, and if the failure were caused by the Atlas, it could mean significant delays for that mission, which used a similar Atlas D derived Atlas LV-3B booster. However, analysis of telemetry data and closer examination of the launch films quickly confirmed the Centaur as the source of trouble. The failure was determined to be caused by an insulation panel that ripped off the Centaur during ascent, resulting in a surge in tank pressure when the LH2 overheated. Beginning at T+44 seconds, the pneumatic system responded by venting propellant to reduce pressure levels, but eventually, they exceeded the LH2 tank's structural strength. At T+54 seconds, the Centaur experienced total structural breakup and loss of telemetry, the LOX tank rupturing and producing an explosion as it mixed with the hydrogen cloud. Two seconds later, flying debris ruptured the Atlas's LOX tank followed by complete destruction of the launch vehicle. The panel had been meant to jettison at 49 miles (80 km) up when the air was thinner, but the mechanism holding it in place was designed inadequately, leading to premature separation. The