The WAC Corporal was the first sounding rocket developed in the United States. The Corporal program was started by the US Army's Ordnance and California Institute of Technology organization (ORDCIT) in June 1944 with the ultimate goal of developing a military ballistic missile by developing the technology necessary. The California Institute of Technology (Caltech) had been fostering a group of rocket enthusiasts known informally during the 1930s as the "suicide squad", which was financed by the Guggenheim Aeronautical Laboratory (GALCIT) since the mid 1930s. Some of the GALCIT enthusiasts had founded a business to manufacture rocket motors named Aero Jet.
During the first years of WWII, GALCIT had pursued the development of both solid and liquid fueled Jet Assisted Take Off (JATO) boosters to aid aircraft take off performance. As the group had experimented with rockets for several years before the war they were selected by the Army to pursued ballistic rocket development.
The first rocket designed by the group for the Army was the XFS10S100-A, also known as the Private, that being the first Army enlisted rank. The second ORDCIT project, which became the Corporal, named for the next Army enlisted rank, was a project originally named XF30L 20,000. The Corporal project envisioned a liquid propellant missile of 30 inch diameter and a power of 20,000 pounds thrust. The Signal Corps had created the requirement for a sounding rocket to carry 25 pounds of instruments to 100,000 feet or higher. This was merged with a requirement of the Rocket R&D Division of the Ordnance Department for test vehicle. Frank Malina of 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. This program became the WAC Corporal which had no guidance aside from stabilizing fins. Thus the name Without Attitude Control (WAC).
The theoretical work setting the stage for the WAC Corporal was established in a 1943 paper "A Review and Preliminary Analysis of Long-Rage Rocket Projectiles" by Malina and Hsue-Shen Tsien (Qian Xuesen). Design of the WAC Corporal 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 (The "WAC Corporal")." The final design work was by a relatively new method for America rocketry involving a team of persons specializing in particular areas and involved significant efforts to derive performance from theoretical means. The key persons responsible were M.M. Mills (booster), P.J. Meeks (sounding rocket), W.A. Sandburg and W.B. Barry (launcher and WAC nose), S.J. Goldberg (field tests) and H.J. Stewart (external ballistics) and G, Emmerson (photography).
For propulsion, the 38ALDW-1500 Aero Jet liquid fueled engine was chosen. That engine had been developed as a jet assist take off (JATO) system for Navy flying boats. The 38ALDW-1500 was modified for hypergolic fuel with red fuming nitric acid as the oxidizer and furfuryl alcohol as the fuel. It was intended to use a booster derived from the Tiny Tim air to ground attack rocket to propel the WAC Corporal from a tower to gain sufficient velocity for the WAC Corporal's three tail fins to provide stabile guidance. Despite the emphasis upon a theoretical approach it was deemed necessary to empirically prove the aerodynamics of the WAC Corporal, especially the three fin configuration, so a 1/5th solid propellant scale model called the Baby WAC was tested from a scaled down launcher in July 1945. Four Baby WACs were flown.
The design of the WAC Corporal was innovative in that it had a monocoque structure containing the oxidizer, fuel, and pressurizing air tanks and three rather than four stabilizing fins as the Army preferred. As the WAC Corporal was conceived as an atmospheric sounding rocket to be utilized in part near populated locations it was provided a parachute recovery system triggered by two systems along with a separate system for recovering the Signal Corps radiosonde nose cone with its own parachute.
The production of the WAC Corporal was by Douglas Aircraft Corporation with critical parts supplied by JPL and the engines by Aerojet.
The WAC Corporal test program began at White Sands proving grounds on late September 1945 with a series of booster tests which ultimately lofted dummy WAC Corporals. These were the first missiles launched at White Sands. They were launched from what became LC-33 which was also the launch site for many other early missiles including the V-2, Viking and Hermes missiles. These first tests provided checks upon not only the booster but the launcher and firing controls as well as providing practice for the radar and camera crews. October saw two launches of WAC Corporals with 1/3rd loads of propellants. They were followed by six fully fueled flight during the rest of October 1945. Several of these flights reached altitudes of approximately 235,000 feet. Performance varied because of several factors one of which was that the actual gross weights of the WAC Corporals varied from 683 to 704 pounds and empty weights from 289 to 310 pounds. The missions flown during the WAC Corporal first series were:
The WAC Corporal had succeeded. Radar tracking was difficult and above 90,000 feet the return was too small to be detected. Radiosonde signals were not received. When it is considered that no previous American liquid fueled rocket had exceeded a tiny fraction of the altitudes the WAC Corporal regularly achieved results were quite exceptional. It was decided November 9, 1945 to alter the WAC Corporal design to improve upon it for another series of flights. This redesigned rocket was first deemed Sergeant in keeping with the JPL naming scheme but was soon renamed WAC Corporal B. Sergeant was later used for a solid propellant missile designed for the US Army at JPL. Design of the WAC Corporal B was initiated in March 1946 with P.J. Meeks as Project Coordinator. The WAC Corporal B differed significantly in detail though not its basic shape. The WAC Corporal B was 4 inches longer, weighed 100 pounds less, and it contained 40 pounds less propellants. The design of the fuel pressurization system and fuel valves was simplified. It had a redesigned shorter engine with redesigned injectors weighed 12 pounds rather than the longer 50 pound engine of the WAC Corporal A,. The drastically redesigned rocket body utilized separate tanks of dissimilar materials. Larger, lighter fins were supplied which proved problematic on the first WAC Corporal B flight on December 6, 1946. The flights during the second series of WAC Corporal flights were:
The WAC Corporal program was an extremely successful test program. The last 6 WAC Corporal Bs to fly were used in the Bumper program. They were used as the second stage on the V-2 first stage in the first staging experiment. For Bumper the WAC Corporal was modified to provide stability in excess of Mach 5 by increasing the number of fins to four and increasing their size. The WAC Corporal had to be modified so that the engine ignition would be initiated by the integrating accelerometer of the V-2 stage just before cutoff of the V-2 engine. The WAC Corporal was to be spin stabilized by two solid rockets placed between the oxidizer and fuel tanks. The Bumper/WAC had a payload capacity of 50 pounds and it carried a doppler transmitter/receiver which transmitted the nose cone temperature as well as velocity information. There were 6 Bumper flights from White Sands. The first two from WSPG carried solid fueled dummy WACs. Flight number six saw the V-2 fail. The last two flights, Bumper 7 and 8 were the first launches from the new Joint Long-Range Proving Ground at Coco Beach, Florida later known as Cape Canaveral. The reason for the move was the intention to use a depressed trajectory to achieve velocities in the vicinity of Mach 7 at 120,000 to 150,000 feet. As this would entail flights in excess of 250 miles range which would exceed the boundaries of the White Springs Proving Ground. The WAC/Bumper flights were:
Bu-7's WAC Corporal, the last one ever to fly, achieved Mach 9 which was the highest speed then ever achieved by an projectile in the atmosphere. The WAC Corporal was involved in the first flights from both White Sands and Cape Canaveral.
The WAC Corporal found itself in direct competition in its designed role with the V-2 offering much larger payload capabilities which became available in the GE operated Hermes program in April 1946. It was also in competition with the Aerobee an enlarged WAC Corporal which was tested in late 1947 and became fully operational in spring 1948. The Aerobee sounding rocket was developed for the Applied Physics Laboratory and Naval Research Laboratory but was designed by Aero Jet Engineering Corporation and was thus a direct descendant of the WAC Corporal and was powered by the 45AL-2600 engine, a direct development of the 38ALDW-1500 of the WAC Corporal. Another competitor as a sounding rocket was the Neptune, later the Viking. The payload of the V-2 was around 1 ton, the Aerobee around 150 pounds. Viking which could soon loft 500 pounds to 100 miles was another competitor. All of them overwhelmed the 25 pound capability of the WAC Corporal. The final consideration was costs. In terms of pounds to altitude per dollar the WAC Corporal lost to the competition. Each WAC Corporal B cost $8,000, Each V-2 reassembled from captured parts cost around $30,000. The Aerobee cost $18,500, and the Navy's Viking $200,000 in late 1947 While the WAC Corporal was soon replaced in its intended role of sounding rocket and thus lapsed into obscurity it had echos lasting for 66 years. Its 38ALDW-1500 was the direct predecessor of not only the Nike Ajax A21AL-2600 and Aerobee's 45AL-2600. It was developed into the AJ10 series amongst which were the AJ10-37 engine for the second stage of the world's first designed for the role Satellite Launch Vehicle, Vanguard. The AJ10-101 powered the Able second stage which flew on a number of first stages. A direct descendant of the WAC Corporal's engine, the AJ10-137 was the Apollo Command Module engine which took men to the moon and back. The long line of direct WAC Corporal engine descendants ended in the AJ10-190 better known as the Orbital Maneuvering System (OMS) of NASA's Space Shuttle. The WAC Corporal was perhaps the seminal rocket in American space flight. WAC Corporals are exhibits of the National Air and Space Museum and in the White Sands Missile Range Museum.
The origins of the name WAC Corporal have been variously attribute to standing for Without Attitude Control or Women's Army Corps. Determining the truth may be a difficult matter when the subject is obscure, the program was classified and was little covered at the time or soon after. The issue has been addressed by historians of White Sands, who have claimed it means Without Attitude Control. In "Bumper 8 50th Anniversary of the First Launch on Cape Canaveral Group Oral History" Dr. Pickering attributes it to Women's Army Corps. That was challenged at that time by Dick Jones who was a participant in WAC Corporal launches at White Sands and the Cape. A fifty year old memory of a man who was not directly involved may be questioned especially as it was questioned by a participant in the program at the time Dr. Pickering made it.
Further research revealed the oldest open reports of the WAC designation produced three Aviation Week articles which first mentioned the missile. In its March 18, 1946 issue, Aviation Week noted "Under the amusing security code designation of 'WAC Corporal' the project was initiated in 1944 . . ." In the June 1, 1946 of Aviation Week, an article appears which suggests of the WAC Corporal "It is launched from a triangular 100 ft. launching tower, and thereafter goes its own merry way" and that "These 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." The July 8, 1946 issue of Aviation Week has mention of the "'WAC Private' and 'WAC Corporal' being the only publicized models to date. The 'WAC Sergeant,' now under development, is expected to reach an altitude of 100 miles." There was never any "WAC Private". The "WAC Sergeant" was an early appellation for what became the WAC Corporal B. Kennedy, DeVorkin, and Eckles, all White Sands historians who have extensively researched early programs at the Proving Grounds agree that Without Attitude Control is correct. At the very least the issue is in doubt with the evidence in favor of the Without Attitude Control.
Another consideration might be made. In chapter 8 of Strange Angel, a biography of Jack Parsons who was an important member of the GALCIT "suicide squad", there is mention of the rocket fuel GALCIT 27 he developed being referred to as "the goop." A quirky sense of humor was common amongst rocket men in the early years. The LC-33 blockhouse had a light on the panel which would light up "TILT" when a countdown was stopped. There was another which lit up "Aw Shit" if the rocket blew up on the pad. Given the legendary irreverence of the "suicide squad" it could be that the Women's Army Corps" attribution was used in a joking way towards the diminutive WAC Corporal, or perhaps as a way of mentioning the rocket without breaching security.