It is December 21st of 1963, and final preparations are being made to launch the TIROS-8 mission: a Delta B carrying a TIROS H satellite. TIROS (Television Infrared Observation Satellite) was a meteorological satellite manufactured by RCA that carried low-resulution television and infrared cameras for weather observations. This particular TIROS was placed in a polar orbit, and returned over 100,000 cloud cover images while it was on station.

Note that Delta is sometimes referred to as Thor Delta. The Thor Delta was a modification of the Thor Agena vehicle, and its derivatives were usually simply called "Delta" (as in "Delta A", "Delta B", etc.).