
Juno II AM-19F (AM = Army Missile?) stands ready at Launch Complex 26B, Cape Canaveral, to continue the underwhelming heritage & legacy of the Juno II family of launch vehicles, in preparation for its impending failure on 25 February 1961.
Note the date discrepancies. Most sites reference the above.
From the Space Launch Report website:
"Vehicle AM-19F flew next, on February 24, 1961. This was a failed attempt to orbit the 75-lb Explorer S-45 ionosphere beacon satellite, a spacecraft meant to measure the ionosphere’s effect on radio signals. First stage performance was normal, but something went wrong shortly after the stage separated from the guidance compartment. The most likely failure mode was thought to be a sensor cable coming loose from the side of the payload shroud and wrapping itself around the spinning high speed stage cluster. Stage 4 and the payload were likely ripped free from the cluster and the stage 3 and 4 firing timer was likely damaged. Although the instrument compartment regained control of the cluster, only the second stage fired and orbit was not achieved."
At:
www.spacelaunchreport.com/jupiter5.html
And, from Gunter's stellar site:
space.skyrocket.de/doc_sdat/explorer_s45.htm