Aerojet Propellant Research, 1944-1945
 At the end of 1944, the Aerojet research group, headed by Fritz Zwicky, noted astrophysicist at the California Institute of Technology, had completed a Navy contract to investigate high-energy solid and liquid propellants. The results led the investigators to monopropellants; they were enthusiastic over the possibilities of using nitromethane, which has a theoretical exhaust velocity of 2200 meters per second. Zwicky was aware of other Navy-sponsored work on boron hydrides that had potential exhaust velocities of 2800 to 3100 meters per second-considerably higher than nitromethane but also much further from practical utilization.4 At the time of Hall's visit, Aerojet was in the second phase of investigating nitromethane-determination of its experimental performance and handling characteristics. David A. Young and his new assistant, Robert Gordon, were in charge of the work, and Hall asked them about the combustion properties of hydrogen and oxygen.
Gordon had worked on aircraft engines at the power plant laboratory at Wright Field for several years and later was a navigator with the Eighth Air Force in Europe. There he had acquired a first-hand awareness of German competence in jet propulsion.  He took part in bombing Peenemunde, observed the launching of a V-2, and was attacked by ME-163s-the first rocket-powered aircraft. Gordon joined Aerojet in July 1945 and during his orientation, Young introduced him to the fundamentals of rocket theory. Gordon then began calculating theoretical rocket performance of various propellant combinations using the heat of formation of exhaust products. This lead to the consideration of the simplest and most energetic reaction-hydrogen and oxygen-and he asked Young to let him try hydrogen-oxygen in a rocket experiment.5