The 1000 series introduced the ELTT (Extended Long Tank Thor) with the MD-3-III. Delta P was introduced with Delta 1000, which used the Lunar Module Descent Engine derived TR-201 rocket engine.

It selected the fourth iteration of the Thor launcher, Thor-Delta, for its purposes. By May 1960, NASA had launched its first Thor-Delta from Cape Canaveral Air Force Station in Florida.

The liftoff of the last-ever Delta rocket today (April 9) brought with it a change in the way the U.S. sends satellites, interplanetary probes and spacecraft into Earth orbit.

The launch seemed so routine that only a few bird watchers turned out at the Cape Canaveral pad. And as the Thor-Delta rocket rose above the southern morning, the Bell Telephone Laboratories ...

A United Launch Alliance (ULA) Delta IV Heavy rocket carrying the NROL-68 mission for the National Reconnaissance Office (NRO) lifts off from Space Launch Complex-37 at 5:18 a.m. ET, June. 22, 2023.

Delta debuted as a space launch vehicle on May 13, 1960, as the Thor-Delta. NROL-70 marked the 389th launch of a Delta rocket. Irene Klotz.