Delta 2914 was the principal three-stage Delta 2000-series configuration, combining an RS-27-powered extended long-tank first stage, nine Castor II strap-on motors, the 2.44-metre TR-201-powered second stage, and a TE-364-4 solid third stage. Thirty vehicles flew from April 1974 through August 1979. Delta 102 recovered from low first-stage oxygen pressure and completed the SMS 1 mission; Delta 130 placed GEOS 1 into an alternate orbit after a spin-table failure; the other 28 flights achieved their planned launch objectives.