Thor-Agena B at Vandenberg AFB.
Fifty years ago, the US Air Force continued to launch Corona spy satellites disguised as the Discoverer Program. Discoverer 24 launched on June 8, but I have found another source that lists the 16th as the launch date. Considering that Discoverer 25 was also launched on June 16, 1961, leads me to believe the first date of June 8 is probably more correct for D-24. That particular flight launched a KH-5 spay satellite, but as I reported earlier, the mission failed for an unknown reason. By the way, if anyone finds out the correct reason and shows me the facts, I'll be happy to give you credit!
Discoverer 25 is also listed as launching from Vandenberg AFB on June 16, 1961 on a Thor-Agena B rocket. This launch turns out to be successful. In this case, the satellite was the KH-2 model camera system but also included some design changes to the payload. Sensors on the payload tested for cosmic radiation, atmospheric pressure, and micro-meteor impacts. The payload body was an elongated fuselage that had the capability of being re-oriented to face downward with a detachable cone facing the Earth. Once detached, the cone would be tested for retro-rocket slowing and maneuvering. The payload successfully deployed the cone and it was recovered in the Pacific Ocean on June 18th, and the payload structure itself burned up in re-entry on July 12th of 1961.