Firing the V-2 at White Sands
Purpose of the Program
The Army’s purpose in firing V-2’s was two-fold; to gain experience that would be helpful in the design and handling of future guided missiles and to investigate the reaches of the upper-atmosphere. The V-2 was converted from its wartime use as a weapon into a flying laboratory. Its great weight-carrying capacity and high performance provided an excellent vehicle for upper-atmospheric investigation and experiments.
In January 1946, the Army made it known that the V-2 would be used in upper air research and offered Government agencies and universities the opportunity to participate in the program. The Naval Research Laboratory, Army Ground Forces, Air Material Command, Army Signal Corps (Signal Corps Engineering Laboratories), Applied Physics Laboratory (APL) of Johns Hopkins University, Harvard, Princeton, the University of Michigan, and the California Institute of Technology were among those accepting. These initial members formed the “V-2 Upper-Atmospheric Research Panel.”
The program of research into the physics of the upper atmosphere included research in:
(1) Radio frequency propagation and absorption in the ionosphere
(2) Ionic density
(6) Cosmic ray studies
(7) Ultraviolet absorption
(9) Propagation of sound and shock waves
(10) Biological studies
(11) Spectroscope studies
In order to avoid duplication of effort, each agency described the work it was doing or intended to do, and the Panel decided which agency would use each rocket. Thus, each profited from the experience of the others.
Valuable experience was also gained in assembly, pre-flight testing, handling, fueling, launching, or firing, and tracking of large missiles. American-manufactured steering control mechanisms and other missile guidance components were tested. Later, the firings were used to test control guidance of the rocket by radar and to test radar on detection and tracking of supersonic missiles in flight.
In a preset guidance system, the controls of the missiles are set on a predetermined course prior to launching. In determining the course, atmospheric conditions, largest location, and missile performance are taken into consideration. Once the missile is launched, it can only maintain this predetermined direction, attitude or position with respect to a fixed reference and no corrections can be made during flight. This system was used in the V-2 rocket. It used a timing mechanism that caused the rocket to rise vertically for the first few seconds and then pitch over into a specific angle of climb. This angle was maintained until the rocket motor shut off.
Using preset guidance, the V-2 could easily leave the range if some malfunction developed in the steering system after take-off. To overcome this disadvantage, an emergency cut-off of the fuel supply by radio signal from the ground was devised and installed in the missile. It was considered that, while it could not stop the missile, it could at least slow it down. The resulting low velocity could limit the range of the missile and lessen the possibility of damage being done. Through experimentation, missile separation was achieved resulting in recovery of the instrumentation in a reusable condition. Telemetry was successfully developed to operate from the missile to the ground station, transmitting performance data on the operation of the entire system of the V-2.
The first firing of a V-2 at White Sands Proving Ground was made on the static test stand which had been constructed under guidance of the German scientists. The rocket was placed on the stand and held in place by a massive steel structure which incorporated thrust measuring instruments. This test was made on 15 March 1946 and was considered successful in that the motor continued to fire for 57 seconds. The force and heat of the blast ripped loose the heavy steel plates that lined the duct of the test stand. These pieces were heated red-hot and were blown out over the surrounding area. Bushes and grass in an area as much as 250 yards away from the test stand were ignited. However, no great damage was done. It is of interest to note that Major General G. M. Barnes, then Assistant Chief of Ordnance for Research and Development, Ordnance Department was a visitor at the Post that day to witness the first firing the United States of a German V-2 rocket. General Barnes had been one of those most instrumental in the site selection and establishment of White Sands Proving Ground.
The second firing of a V-2 at WSPG was a flight test on 16 April 1946. The motion of the missile was erratic from take-off and flight was terminated after 19 seconds by the newly designed emergency radio cut-off. Photographs and visual observations were the only sources of information on missile behavior and from these it was determined that a carbon jet vane had broken. To correct this fault, the jet vanes of later missiles were X-rayed and given mechanical load tests. These precautionary measures were effective as no other V-2 acted in such manner as to indicate jet vane breakage. Although the rocket reached an altitude of only 18,000 feet, the flight lasted long enough to indicate that changes in the ignition system would be required.
V-2 #3 was fired on 10 May 1946 as a demonstration for the press. The flight rose to an altitude of 70 miles and was considered successful in all aspects. However, as in the two previous firings, the rocket descended intact and exploded on impact. The rocket and instrumentation were completely destroyed.
Physical recovery of instruments after impact was unsuccessful. Frequently, sensitive instruments were unsalvageable or, if recovered, were found to be badly damaged from impact. The V-2 carried a large quantity of experimental equipment and, if research agencies were to profit from the V-2 flights, it was essential that this equipment be recovered after flight and in reasonably good condition. Researchers determined that, if the nose and tail sections were separated from the center sections of the missile body, streamlined facets of the rocket would be destroyed and the denser atmosphere would slow the falling missile parts. In this manner, they would land at a relatively low rate of speed, leading to a better chance to recover the nose cones and the instrumentation they carried.
Several methods of separation were tried. The first attempt was with V-2 #5, fired on 13 June 1946. A four-pound charge of TNT was exploded by radio signal as the rocket was descending. Separation failed and the missile was again destroyed on impact. The first successful separation was achieved with the missile fired on 30 July 1946 (V-2 #9). The warhead separated from the body of the rocket but was buried so deeply in the sand on impact that it was impossible to be recovered. The missile body was retrieved badly damaged but intact.
Various amounts and types of explosives were tested. Engineers tested different locations for the explosive placed in the missile. After extensive experimentation, it was decided that the most effective procedure was to place four pounds of TNT adjacent to the main longerons at the forward end of the control compartment next to the warhead. It was also found that the best results were obtained when separation or “air burst” took place at 40 miles altitude during the descent.
On 22 August 1946, V-2 #11 turned west just four seconds after take-off and at 0.1 miles in altitude. About four seconds later, the missile reached an angle of 70 degrees from vertical and rolled so that one fin was up. It straightened out and continued level flight. Emergency radio cut-off was initiated after 6.5 seconds. A spurious yaw signal resulting from induced potential in the guide-beam circuit of the computer was the cause of the failure.
Ejection of the instrumentation equipment by compressed air proved successful on V-2 #12, fired on 10 October 1946. The flight was termed the most successful as of that date in terms of compilation of scientific data.
Motion pictures of the earth were taken from V-2 #13 fired on 24 October 1946. The best pictures were obtained at an altitude of approximately 65 miles and covered an estimated 40,000 square mile area. Scientists stated the curvature of the earth could be noted. The 35mm camera, with a special magazine with walls of one-inch steel armor, was encased in a duralumin box three-eighths of an inch thick with an opening for the lens. Air burst was successfully achieved at 25,000 feet, but upon impact, the camera was damaged beyond repair. However, the film was recovered in perfect condition. The rocket was also equipped with black powder to be exploded at a given altitude for the study of upper winds. This experiment was only partially successful.
Immediately after firing on 7 November 1946, V-2 #14 began gyrating violently, then stabilized at an altitude of only 300 feet. After the missile had cleared the cantonment area, operators gave the emergency radio cut-off signal and the missile was brought down within the limits of the Proving Ground. The cause for the action of the missile could not be definitively identified, but it was determined that the probable cause was a failure in the roll-yaw gyre or in the on-board computer.
The flight of V-2 #17, on 17 of December 1946, was launched at 2212 hours. This was the first night firing of a V-2 in the United States. The rocket motor had a burning time of 19.6 seconds, the longest of any V-2 fired during the entire program. It also attained a record velocity of 5,402 feet per second. According to a statement made by Colonel Harold R. Turner (Ret.), then Commanding Officer of White Sands Proving Ground, the carbon jet vanes were heated to a red incandescence by the heat of the rocket’s exhaust blast. Dr. Fritz Zwicky of the California Institute of Technology, who had witnessed the firing, stated he believed the vanes could be seen from the Mount Palomar Observatory in California, some 600 miles distant. As the experiment with the black powder charges had been unsuccessful, this rocket was equipped with M-9 rifle grenades to be exploded at a predetermined altitude in an effort to produce artificial meteorites. This experiment also failed.
V-2 #19, fired on 23 January 1947, was equipped with an automatic pilot system developed by the General Electric Company. The experiment was considered successful although the flight distance was less than had been calculated. This special steering system, which could alter the altitude of the rocket in flight, was the forerunner of the first remote-controlled rocket.
One purpose of the experiments conducted with V-2 #27 in October 1947 was to investigate supersonic convective heat transfer. The friction created by the V- 2’s supersonic speed produced intense heat within the missile and the instruments, some delicate, needed protection. But to what extent? Dr. Charles F. Green, a research engineer for the General Electric Company, then stationed at White Sands Proving Ground, stated, in 1947:
“At the Earth’s surface, the temperature is about seventy degrees. You’d expect that the higher a rocket goes, the colder it would get, and when it reaches an area from fifteen to thirty-five kilometers up, the temperature is around minus sixty-seven, but at forty kilometers it’s seventy degrees, the same as the Earth’s surface. At eighty kilometers, it’s 140 degrees, which is hotter than it ever gets here in the desert at White Sands. At 125 kilometers, in the lower part of the ionosphere, it drops again to minus sixty-seven. Two hundred kilometers is the top altitude for which temperatures are known. There, it is really hot – 1,200 degrees. If a supersonic plane is developed, the more we know about heat transference the more we’ll know how much refrigeration the plane will need in order to protect its occupants.”
Special thermometers were placed at six locations on the skin of the missile; four on the nose cone and two on the sides of the missile body. Instruments were also installed to record pressure measurements. In general, the firing was successful in that data were obtained on heat transference at high supersonic speeds. Pressure measurements were also obtained.
Erection of the rocket indicated that more training would be required for the erection crews and a training program was later initiated. The generally good condition of the rocket at impact and recovery tended to indicate that an early air burst resulted in the remainder of the rocket remaining intact.
Under direction of the Applied Physics Laboratory, V-2 #40 was launched just about 76 minutes after AEROBEE #7-A, on 26 July 1948. One purpose of the experiment was to obtain further experience in aerial reconnaissance. Both missiles were instrumented with cameras and 100 feet of film to be taken at the rate of one from every 1.5 seconds; each camera recorded over 200 exposures which developed into excellent photographs. At the peak of the trajectory, the curvature of the earth was clearly discernible, as well as mountains, rivers, cities and highways. When pieced together, the photographs from the two missiles covered what was believed to be the largest section of the earth ever photographed in such a short period of time; a strip approximately 700 miles wide showing 2,700 miles along the horizon, form the northern portion of Wyoming deep into Mexico. The photographs from the AEROBEE covered an area of 300,000 square miles and those from the V-2 covered an area of 800,000 square miles.
On 14 June 1951, V-2 #55 was erected in the launcher and fueled. The preliminary stage developed normally and the main stage was energized and the plugs dropped. Immediately following, there was a violent explosion in the vicinity of the control chamber. An instant later, the missile toppled to the ground where a series of explosions occurred. Study of the excellent photographic coverage obtained disclosed that the missile had lifted perhaps six inches when flashes of flame, caused by the original explosion, appeared at the locations of the TNT used for air burst. One frame showed a bright streak where the primacord ran from the TNT to the nose cone. After all possible causes had been investigated, it was determined that the explosion was caused by the squib short-circuiting pins making contact with energized points on the ground plugs as the missile thrust fluctuated prior to take-off. In other words, air burst was affected at take-off.
Several missiles went astray during the early part of the program. One V-2, after taking off on an erratic course, narrowly missed he cantonment area and a party of visiting dignitaries. One landed near Alamogordo, New Mexico and one crossed the Organ Mountains and emergency radio cut-off was used in order to keep it within the boundaries of the Proving Ground. If it had continued on its course, the probable point of impact would have been San Antonio, New Mexico.
The most noted missile to go off-range was a V-2 fired on 29 May 1947. A faulty gyroscope caused the missile to change course at a high altitude and head south. Apparently this change of course occurred near burn-out as the emergency radio cut-off had little or no effect. The missile continued on its trajectory and landed 1.5 miles south of the city of Juarez, Mexico. No damage was done, although the rocket narrowly missed an ammunition dump where Mexican mining companies stored powder and dynamite.
These firings forcibly brought the question of range safety to the attention of the Command. Operations were ordered suspended until the Chief of Ordnance was assured that future missiles would be controlled. As a result, a complex and effective safety system was devised.
A 1955 brochure by General Electric detailing work done with the American V-2 Project.