1963-05-29 USA Titan II Test for Gemini Program

A Titan II test cover featuring a “Swanson” stamped cachet, postmarked at Cape Canaveral with a hand cancel on May 29, 1963.

The Titan II was being developed as the launch vehicle for Project Gemini, but engineers faced a serious vibration problem known as POGO—a potentially dangerous longitudinal oscillation caused by interactions between the rocket’s propellant system, engines, and structure.

The May 29, 1963 Titan II N-20 test, launched from Cape Canaveral Launch Complex 16, was part of NASA and the U.S. Air Force’s effort to solve this problem. N-20, the 19th Air Force Titan II research-and-development flight, carried a proposed POGO-suppression system using oxidizer standpipes and fuel accumulators, designed to disrupt the feedback that produced the vibrations. However, the flight failed approximately 55 seconds after launch, before useful POGO data could be obtained. The failure was not attributed to the POGO-suppression equipment itself.