The Delta 1000, 2000 and 3000 series used surplus NASA Apollo program rockets engines for its first and second stages.

The first stage was an Extended Long Tank Thor, re-engined with the Rocketdyne RS-27 replacing the earlier MB-3-III engine.

Launches which required a three-stage configuration in order to reach higher orbits used the Thiokol Star-37D or Star-37E upper stage as an apogee kick motor.

The single failure being the maiden flight, 19 January 1974, which placed Skynet 2A into a useless orbit.

[1] The cost of each launch was estimated on average at $28.52 million, depending on the combination of carrier rocket.