|Function||Expendable launch system|
|Country of origin||United States|
|Launch sites||Cape Canaveral LC-17|
|First flight||6 November 1965|
|Last flight||1 April 1971|
The first stage was a Thor missile in the DSV-2C configuration, and the second stage was the Delta E, which was derived from the earlier Delta. Three Castor-1 solid rocket boosters were clustered around the first stage. Two different solid-fuel upper stages were available; an Altair-2 was used on the baseline version, however this could be replaced with an FW-4D to increase performance. A Delta E with the FW-4D upper stage was designated Delta E1. Six flights used the Delta E configuration and seventeen used the Delta E1.
Delta E rockets were launched from Cape Canaveral Air Force Station Launch Complex 17 and Vandenberg Air Force Base Space Launch Complex 2E. All 23 flights were successful. On December 16 1965, a Delta E launched the Pioneer 6 space probe.