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Hydyne is a mixture of 60% unsymmetrical dimethylhydrazine (UDMH) and 40% diethylenetriamine (DETA), developed in 1957 at Rocketdyne for use in liquid-fuel rockets.[1][2][3] Hydyne was used as the fuel for the first stage of the Juno I rocket that launched Explorer 1, the first successful satellite launch conducted by the United States.

Improved performance[edit]

Mary Sherman Morgan, a chemical engineer at Rocketdyne's propulsion research thermodynamics unit and a leader in the development of Hydyne, first started work on the new compound early in 1956. The problem faced by Morgan and the company's chemical engineers was to replace the PGM-11 Redstone fuel (including 25% water and 75% ethyl alcohol) with a compound that would boost the rocket's performance enough to launch a small satellite into orbit. .[4]

The Jupiter-C and Juno I rockets used the same first-stage engines as the missile, but needed more thrust due to the increased size of the payload/warhead. With the use of the newly developed Hydyne, composed of a blend of 60% unsymmetrical dimethylhydrazine (UDMH) and 40% diethylenetriamine (DETA),[3] the Jupiter-C and Juno I engines gained a 12% increase in thrust and higher specific impulse.[5] The resulting fuel was not only more powerful fuel than alcohol, but also more toxic.[6] The first Hydyne-powered Redstone R&D flight took place on November 29, 1956.[7] After the three Jupiter C and six Juno I launches[8] including the launch of America's first satellite, Explorer I), Hydyne was discontinued in favor of higher performing fuels.

Unofficial name[edit]

'Bagel' was the whimsical name suggested by Morgan, who engineered the Hydyne-LOX (Liquid OXygen) propellant combination used by North American Aviation in their early U.S. rocket designs of the incipient space race. Morgan was considered a rocketry pioneer as she was the only female technical analyst employed by NAA in Downey, California.[9] Morgan suggested calling her new fuel invention 'Bagel', allowing the Redstone propellant combination to be then called 'Bagel and LOX' (a tongue in cheek reference to the brined salmon, Lox, which is served with bagels and cream cheese).[1][2] Her suggested name for the new fuel was not accepted, and 'Hydyne' was chosen instead by the U.S. Army.

Popular culture[edit]

The creation of Hydyne was dramatized in a stage play entitled Rocket Girl which relates the historical account of Mary Sherman Morgan's invention of Hydyne. The play was written by Morgan's son, George D. Morgan, and premiered at the California Institute of Technology in November, 2008, .[2]


  1. ^ a b Morgan, George. It was created by Mary Sherman Morgan. America's First Lady of Rocketry, Caltech News, California Institute of Technology, Vol.42, No.1.
  2. ^ a b c Lerner, Preston, "Soundings: She Put The High In Hydyne". Air & Space Smithsonian Magazine, March 2009, Vol.23, No.6, pp.10, ISSN 0886-2257.
  3. ^ a b NASA. The Mercury-Redstone Project, p. 2-2.
  4. ^ Missiles and Rockets. American Aviation Publications. January 1958. Retrieved 7 June 2013. Nicknamed Hydyne 
  5. ^ George Paul Sutton (2005). History of liquid propellant rocket engines. American Institute of Aeronautics and Astronautics. p. 413. ISBN 1-56347-649-5. 
  6. ^ NASA. The Mercury-Redstone Project, p. 3-2, 4-42.
  7. ^ History of the Redstone Missile System, p. 60
  8. ^ History of the Redstone Missile System, p. 166
  9. ^ "America's First Lady of Rocketry" (PDF). California Institute of Technology. 2008. Retrieved 2013-06-05.