The Atlas/Centaur Launch Vehicles have evolved to
the major Lockheed Martin launch vehicle product line, so I thought it was time
to write about Atlas Centaur! There is
much information on the Internet on Atlas/Centaur (see the references) which I
have tried to summarize below. Also, I
met Ed Bock at the MARS picnic in September.
Ed spent most of his career with General Dynamics in
Atlas has evolved over a period of five
decades, from an ICBM to one of the world’s premier expendable Space Launch
Vehicles. General Dynamics Convair
originally developed the Atlas for the USAF; it first flew in 1957 and was
first deployed as an ICBM in 1959. A
series of Atlas vehicles were adapted from the ICBM models for use by USAF and
NASA from the mid 60’s to the mid 90s. After the Space Shuttle Challenger accident in
1986, General Dynamics (and later Lockheed Martin) developed four versions of
the Atlas: I, II, III, and V** which flew from 1990 to the present. The Centaur,
All Atlas models (except Atlas V) and the Centaur were unique in their use of balloon tanks for propellant. The fuel and oxidizer tanks were made of very thin stainless steel with minimal or no rigid support structures. Pressure in the tanks provided the structural rigidity required for flight and ground transportation. An Atlas rocket (or Centaur) would collapse under its own weight if not kept pressurized (ref 1.) The Atlas V was changed to a rigid aluminum fuselage like that of the Titan vehicles instead of the balloon tanks.
Atlas had
its origins in a Convair contract with the US Army Air Force in 1946, which
showed that balloon
tanks and gimbaled rocket engines were valid concepts. A brillant Convair engineer
named Karel “Charlie” Bossart was the primary force behind the concepts. (Ref.
7,8). The first operational Atlas ICBM,
a D model, was placed on alert at Vandenberg AFB on
In the early 1960’s, an upgraded
Atlas ICBM D model was selected by NASA as the launch vehicle for the manned
orbital Mercury flights. All four
orbital missions were successful. John
Glenn flew the first orbital MA-6 mission in February 1962 and Gordon Cooper
flew the final MA-9 mission in May 1963 (Ref. 1). In the mid 60s, Convair used the ICBM D, E,
and F Atlas models to develop the Atlas-Agena and Atlas-Centaur launch vehicles
for the Air Force and NASA. These
vehicles successfully flew 314 missions (with 33 failures) from the mid 1960s
to 1995. The last ICBM
model of an Atlas vehicle was launched from Vandenberg AFB in 1995. (Ref.7)
The
Atlas I launch vehicle was built by General Dynamics for the Navy, NASAA, and
commercial customers after the Challenger accident to assure access to
space. It was derived from the Atlas G,
and included the same basic vehicle components (Atlas booster and Centaur upper
stage). Significant guidance and control system improvements already
incorporated in the G model such as replacing analog flight control components
with digital units interconnected with a digital data bus were included in the
Atlas I. The first flight of an Atlas I was on
Atlas II with
its Centaur upper stage was designed to launch payloads into low earth orbit,
geosynchronous transfer orbit (GTO), or geosynchronous orbit. The original
Atlas II model was developed to support the United States Air Force Medium
Launch Vehicle II program. The first
Atlas II flew on
Atlas III was
developed after Atlas came to
The first
flight of the Atlas V was
Ed’s paper describes the concept of Continuous Improvement (CI) and how it was evolved for the Atlas Centaur family. He describes the early attitude at General Dynamics and the Government customers toward changing the configuration of an Atlas or Centaur “was that any change other than a mandatory ‘make it work’ fix was risky and to be avoided”. He asserts that “’change is bad” philosophy resulted in significant work force frustration” and “manufacturing and launch processing costs were driven ever higher.”
Starting with the Atlas II commercial program in 1990 (Ref.4), Ed explains that the culture on the Atlas Program changed. The prevalent “change is bad” philosophy gave way gradually to a more flexible “CI “ philosophy. Ed states, ” The Atlas II commercial program adopted and institutionalized the philosophy of CI and a straightforward, non–bureaucratic process for evaluating and accepting improvement changes was instituted, along with a rigorous Systems Engineering assessment and approval process. Expendable launch vehicles offer the optimum platform for CI – each vehicle performs its mission, and then is discarded. Configuration control need only last until each vehicle is launched.”
How did this CI philosophy affect cost and reliability? Ed says that “Atlas became cost competitive with Ariane and other international launch vehicles … and beginning with Atlas II, Atlas has achieved 100% mission reliability. This includes 79 flights since March 1993 and encompasses 10 first of a kind vehicle configurations. The Atlas Program has demonstrated that CI, when implemented correctly, is a key ingredient to mission success.”
For those interested in more information on both the history and especially the capabilities of the Atlas V family of vehicles, I recommend the Lockheed Martin web sites (References 4 & 5). Anyone interested in sharing personal history stories about Atlas, I invite you to contact me. (303-795-1218)
References:
*Ed Bock delivered his Continuous Improvement paper in 2005
to the University of Washington Department of Aeronautics and Astronautics on
the occasion of his selection as Distinguished Alumni for that year. Later in
that year he delivered the same paper to the Atlas Program Product Integrity
Engineers in
**The IV designation was not used to avoid confusion with the Ariane 4, a competing French launch vehicle.