The WAC Corporal was the first sounding rocket developed in the United States and the first vehicle to achieve hypersonic speeds.

[1] It was an offshoot of the Corporal program, that was started by a partnership between the United States Army Ordnance Corps and the California Institute of Technology (named "ORDCIT") in June 1944 with the ultimate goal of developing a military ballistic missile.

[2] The California Institute of Technology had been fostering a group of rocket engineers in the 1930s at their Guggenheim Aeronautical Laboratory (GALCIT) including Frank Malina, Jack Parsons, and Edward Forman.

[5] During the first years of World War II, GALCIT had pursued the development of both solid and liquid-fueled Jet Assisted Take Off (JATO) boosters to aid aircraft take off performance.

[8] The Signal Corps had created the requirement for a sounding rocket to carry 25 pounds (11 kg) of instruments to 100,000 feet (30 km) or higher.

[9] Frank Joseph Malina of the Jet Propulsion Laboratory (JPL) proposed the development of a liquid-fueled sounding rocket to meet this request, thus providing a practical developmental step towards the ultimate Corporal missile.

[10][11] The theoretical work setting the stage for the WAC Corporal was established in a 1943 paper "A Review and Preliminary Analysis of Long-Range Rocket Projectiles" by Malina and Hsue-Shen Tsien.

[12][13] Design was started by Frank Malina and Homer Joe Stewart to meet the Signal Corps' request with their study "Considerations of the Feasibility of Developing a 100,000-ft. Altitude Rocket.

"[14] The final design work was done by a team of persons specializing in particular areas and involved significant efforts to derive performance from theoretical means (a relatively new method for America rocketry).

[21][15] Despite the emphasis upon a theoretical approach, it was deemed necessary to empirically prove the Corporal's aerodynamics, especially the three fin configuration, so a solid propellant one-fifth scale model called the Baby WAC was tested from a scaled-down launcher in July 1945.

[33] No previous American liquid-fueled rocket had exceeded a tiny fraction of the altitudes the WAC Corporal regularly achieved.

[52] The WAC Corporal found itself in direct competition in its designed role, with the V-2 offering much larger payload capabilities that became available in the General Electric-operated Hermes program in April 1946.

[62][63][64] In "Bumper 8: 50th Anniversary of the First Launch on Cape Canaveral, Group Oral History," William Pickering attributed it to "Women's Army Corps".

[65] The earliest public reports of the WAC designation are a series of Aviation Week articles, which seem to support "Women's Army Corps" being the derivation of the acronym.

In its March 18, 1946 issue, Aviation Week noted, "[u]nder the amusing security code designation of 'WAC Corporal' the project was initiated in 1944...." In the June 1, 1946 of Aviation Week, an article describes how the WAC Corporal "is launched from a triangular 100 ft. launching tower, and thereafter goes its own merry way," and claims that "[t]hese characteristics suggest some of the reasons for the female appellation of the 'WAC,' the 'Corporal' coming from the fact that some Army rockets are designated by familiar ranks."