Robert H. Goddard flew the world’s first successful liquid-fueled rocket in Auburn, Massachusetts, using liquid oxygen and gasoline. Although the flight was short, it proved that liquid propellants could work in practice, not just in theory. This milestone helped set the technical foundation for later U.S. military interest in rockets.
With new funding support, Goddard moved major flight testing to Roswell, New Mexico, where he could run repeated rocket trials with fewer safety and space constraints. Over the next decade, he improved engines, fuel systems, and rocket stability through practical experiments. Even though this work was not a formal Army or Navy program, it influenced later U.S. designs by demonstrating workable engineering approaches.
A rocket research project began at Caltech’s Guggenheim Aeronautical Laboratory (GALCIT) under Theodore von Kármán’s leadership. The group tested early motors and began building a team that connected academic engineering to military needs. This created a path from university experiments to Army and Navy rocket hardware.
As U.S. military planning accelerated before World War II, rocket-assisted takeoff (JATO) became an urgent priority to help heavily loaded aircraft take off from short runways and ships. GALCIT’s work drew government support and pushed rockets from “lab curiosities” toward practical flight equipment. This demand also encouraged industry partnerships needed for mass production.
GALCIT demonstrated JATO rockets to the U.S. Army, showing that small rocket motors could provide a real takeoff boost. These demonstrations helped convince military decision-makers that rockets could solve immediate operational problems, not only long-term space goals. The results directly increased pressure to build rockets at scale.
The U.S. Navy started development of the Mousetrap system as a rocket-propelled way to attack submarines from surface ships. Unlike some earlier devices that stressed ship decks, Mousetrap used rocket propulsion and rail launchers to throw explosive charges forward. It showed how rockets could be adapted for naval combat roles beyond aviation.
The U.S. Army and its research partners developed the 4.5-inch M8, an unguided solid-fuel rocket intended for use from aircraft and ground launchers. The design reflected growing wartime interest in simple rockets that could be produced in very large numbers. The M8 became one of the most widely manufactured U.S. rockets of World War II.
To move from research to production, members of the GALCIT rocket team helped create Aerojet Engineering Corporation. The new company focused on building JATO rocket motors for military use, filling a gap Caltech could not legally or practically cover as a research institution. This step marked an early U.S. shift from experimental trials to industrial rocket manufacturing.
The M8 family entered service and was used by U.S. Army and Army Air Forces units as an unguided “barrage” weapon, often fired in salvos. This made rockets a practical supplement to artillery and air-delivered ordnance, especially where quick saturation fire was needed. Field experience also revealed accuracy limits, shaping later improvements.
The rocket program at Caltech formally took the name Jet Propulsion Laboratory (JPL) and became an Army facility operated by the university. This change strengthened military control and funding while keeping the research-and-test culture that had produced JATO. It also positioned JPL to support Army work on longer-range rockets and early missile concepts.
The 5-inch High Velocity Aircraft Rocket (HVAR), nicknamed “Holy Moses,” entered World War II combat use and proved highly effective for attacking ships and ground targets. The Smithsonian notes the HVAR was first used by the U.S. Army Air Forces against targets near Lo, France, in July 1944, and then saw wide use by Navy aircraft. The HVAR represented a major improvement in speed and impact over earlier aircraft rockets.
The U.S. Army supported flight testing of the “Private” experimental rocket series, designed to explore fin-stabilized ballistic flight and multi-stage configurations. These tests provided proof-of-concept data for rockets that behaved more like future ballistic missiles than short-range battlefield rockets. The work helped set up the postwar shift toward dedicated Army missile programs.
With the European war ending, U.S. Army and Navy rocket development moved from urgent battlefield needs toward longer-term missile and guided-weapon planning. Wartime experience with JATO, shipborne rockets, and air-to-surface rockets had established manufacturing capacity and operational tactics. This transition closed the 1926–1945 phase of early U.S. military rocket trials and set the stage for postwar ballistic missile programs.
U.S. Army and Navy Early Military Rocket Trials (1926–1945)