Delta 2310 was a two-stage Delta 2000-series configuration with the RS-27-powered extended long-tank first stage, three Castor II strap-on motors, and the TR-201-powered second stage without a solid third stage. All three flights succeeded, launching NOAA 4, NOAA 5, and the Solar Mesosphere Explorer between 1974 and 1981.
Future launches and major activity directly linked to this vehicle family.