The facility was constructed by the United States Air Force in the late 1950s for the Titan I missile program, alongside LC-19, LC-16, and LC-15 to the south.

Following being mothballed for two decades, SLC-20 saw life with further modications in the late 1980s for the Starbird launch vehicles[2] associated with the shuttle Starlab mission.

To support upcoming operations at Cape Canaveral, Firefly plans to develop both manufacturing facilities at a nearby Space Florida business park as well as the launch site.

This compliments a similar lease arrangement made with the military for SLC-2W at Vandenberg Space Force Base as a launch site used for polar orbital trajectories.

[6][7] As SLC-2W had a much more active history of being used as a launch pad (being the Western Range site of the Delta II), Firefly opted to prioritize work on there over SLC-20, seeing the maiden flight of the Alpha in September 2021.