Spaceline - Covering the Past, Present and Future of Cape Canaveral

Contact Spaceline

Spaceline Home/Site Index

Launch Schedules

Spaceline Logo Cape Canaveral Florida

spaceline, inc.

About Spaceline

Spaceline Photo Gallery

Gift Shop








Written and Edited by Cliff Lethbridge


Evolving directly from the U.S. Air Force Thor IRBM, the Delta space launch vehicle was designed for NASA in 1959 to handle a variety of satellite payload applications.

Manufactured by Douglas Aircraft, which became McDonnell Douglas, the Delta family gave NASA a firm, reliable foundation for launching intermediate-weight civilian payloads.

Although originally considered a temporary, interim vehicle to meet NASA requirements of that era, the Delta launch vehicle continued to evolve to meet the ever-increasing demands of the civilian and commercial satellite industry, and remains in use today.

The non-military nature of the original Delta vehicle is historically significant, since it was the reason the booster family was given the name it still holds.

The military Thor IRBM had already been adapted for satellite launches prior to the introduction of the Delta vehicle.

The first three Thor-based satellite launchers were called Thor-Able, Thor-Able-Star and Thor-Agena A, based on the respective names of the rocket's upper stage configurations.

The intended name Thor-Delta represented the fourth upper stage configuration for the Thor-based space launch vehicle, because Delta is the fourth letter of the Greek alphabet.

Since the vehicle was designed primarily to be a civilian satellite launcher, the name Thor was eliminated so that the rocket could be better distinguished from its military relatives.

The same basic principle was applied in the late 1950's as the short-lived Redstone MRBM-based and Jupiter IRBM-based rockets were renamed Juno I and Juno II, respectively, for civilian satellite launching applications.

But as far as modern missile-descended rocket families are concerned, the Delta is unique in this regard. The Atlas and Titan rocket families never dropped the names of their military ancestors.

While rockets carrying the Thor name continued to launch military satellites from Vandenberg Air Force Base, California well into the 1970's, the Delta family has served with distinction as one of the longest-lived programs on the Cape.

Copyright 2012 Spaceline, Inc.