HISTORIAN'S CORNER - October, 2006

BY: MattGrogan

            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 San Diego working on the Atlas and Centaur vehicles and his help with this article is much appreciated.  Ed came to Denver in late 1994, soon after Martin Marietta acquired the Atlas Program from General Dynamics, and he retired in 2000 as VP and Program Director of Atlas Recurring Programs.  In 2005, Ed wrote a paper on “Continuous Improvement” (CI) and its application to Atlas/Centaur; I included some of the concepts from that paper in the final paragraphs below*. 

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, America’s first high-energy liquid hydrogen/oxygen upper stage, achieved its first successful flight in 1963.  Convair originally developed the Centaur for NASA to serve as the Atlas upper stage for the Surveyor spacecraft missions.  Surveyor soft-landed on the Moon five times in the mid 1960’s to assess lunar surface conditions for Apollo. (Ref. 2)

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 October 31, 1959, by the USAF 576th Strategic Missile Squadron.  It was stored horizontally above ground, as were the other 32 Atlas D models that were deployed.  Subsequent Atlas E models also stored horizontally but in below ground level hardened “coffins”.  The F model was the first ICBM to be stored vertically in underground silos and raised by an elevator to an above ground position for launch.  At the deployment peak in 1962, 144 Atlas D, E, and F model ICBMs were in service. In 1964, the Air Force replaced the Atlas fleet with Titan and Minuteman.

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 July 25, 1990.  Eleven flights were attempted and 8 were successful.  The last flight was on April 25, 1997.  (Ref.2)

         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 7 December 1991.  Sixty-three launches of the Atlas II, IIA and IIAS models were carried out between 1988 and 2004, all successful. Atlas II provided higher performance than the earlier Atlas I by using engines with greater thrust and longer propellant tanks for both stages.  This series also used an improved Centaur upper stage to increase its payload capability. Atlas II also had lower-cost electronics, and an improved flight computer. (Ref. 1)

         Atlas III was developed after Atlas came to Denver.  It flew between 2000 and 2005.  It was the first member of the Atlas family to feature a "normal" staging method, compared to the previous Atlas “stage and a half variants”, which were equipped with Rocketdyne jettisonable engines on the first (sustainer) stage.  Atlas III consisted of two stages. The first stage was new, but the upper stage was the Centaur, which had been used on both Atlas and Titan since the 1960s, and is still in use today on the Atlas V.  The first stage engines were Russian RD-180s, which are also used by the Atlas V.  The RD-180 is produced in Russia by Energomash through an agreement with Pratt & Whitney (Ref. 6).  The maiden flight of the Atlas III occurred in May 2000, and its 6th and last flight (all successful) was February 3, 2005.

         The first flight of the Atlas V was August 21, 2002 and all 8 missions have been successful.  The Atlas V is the current Lockheed Martin family of launch vehicles and uses a single-stage main engine, the Russian RD-180, and the newly developed Common Core Booster (CCB) with up to five strap-on solid rocket boosters.  It incorporates a rigid framework for its first stage booster much like the Titan family of vehicles.  The Centaur upper stage uses a pressure stabilized propellant tank design and cryogenic propellants. The inertial navigation unit (INU) located on the Centaur provides guidance and navigation for both Atlas and Centaur, and controls both Atlas and Centaur tank pressures and propellant use. The Centaur engines are capable of multiple in-space starts, making possible insertion into low-earth parking orbit, followed by a coast period and then insertion into GTO. (Ref 1, 3, 4,5)

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:

  1. Wikipedia.org
  2. astronautix.com/craft/surveyor.htm
  3. geocities.com/launchreport/atlas3.html
  4. lockheedmartin.com/wms/findPage.do?dsp=fec&ci=14917&sc=400
  5. Sowers, George – “Evolved Atlas to Meet Space Transportation Needs” lockheedmartin.com/data/assets/12378.pdf
  6. answers.com/topic/rd-180
  7. daviddarling.info/encyclopedia/A/Atlas_rocket.html
  8. astronautix.com/lvfam/atlas.htm

 

*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 Denver.”

 

**The IV designation was not used to avoid confusion with the Ariane 4, a competing French launch vehicle.