On November 27, 1963 at 19:03:23 GMT, AC-2 (Atlas 126D and Centaur stage #2) took place five days after President Kennedy's assassination. The redesigned Centaur stage functioned without any problems and performed a single burn to geostationary transfer orbit (GTO) (orbit of 474 x 1586 km, inclination of 30.4° and period of 105.8 minutes), where it remains in 2021. The insulation panels were permanently attached to the stage as the jettison problem had still not been solved. Vibration data proved that the panels would have prematurely detached had they not been bolted down. The ultimate fix to the panel problem added more dry mass to Centaur, further dropping its payload capacity. This Atlas-Centaur 2 launch vehicle was used for performance and structural integrity tests. It carried a payload of 4621 kg and instrumented with 907 kg of sensors, equipment, and telemetry.
(Reference from Atlas-Centaur)
