[3] One of two Atlas-Agena pads at VAFB, SLC-3E was originally the designated facility for MIDAS (Missile Defense Alarm System) launches and hosted its first flight on July 12, 1961.

The pad was mothballed for a decade, then returned to use in the late 1970s for NAVSTAR communications satellites on refurbished Atlas E/F missiles.

SLC-3E was then converted for the Atlas H (Atlas-Centaur core with a solid upper stage in place of the Centaur) and hosted ELINT satellite launches from 1983-87.

[7] It was reported in 2003 that SLC-3E would be overhauled to serve as a launch platform for the Atlas V.[8] Renovations of SLC-3E began after a January 2004 ground breaking ceremony.

[9] In July 2004, Lockheed Martin announced the arrival of the fourth and final segment of the fixed launch platform (FLP).

[12] United Launch Alliance (ULA) inherited the pad in December 2006 when the company was formed as the joint venture of Lockheed Martin and Boeing, and continued to use it to fly Atlas V rockets.