Mr. Alexander C. Charters

In 1938, Dr. Alexander C. Charters received his PhD in Aeronautics and Mathematics from the California Institute of Technology and, after a year of post- doctoral studies, joined the newly established Ballistic Research Laboratory (BRL) at Aberdeen Proving Ground, Maryland. With war enveloping Europe and the Far East, Dr. Charters joined the scientific staff of the BRL in a period of rapid expansion of the research facilities and capabilities to meet the inevitable involvement of the United States in World War II. One of Dr. Charters initial scientific advancements at BRL was the development of the first reliable spark photography instrumentation for experimental measurement of the aerodynamic properties of projectiles, bombs and rockets. The first spark photograph of a 0.30 cal projectile in flight was taken on June 28, 1940. Dr. Charters was instrumental in developing the needed triggering devices that would subsequently allow the installation of a series of timed spark cameras to be used to measure the drag, lift and moment of a projectile. In 1940, Dr. Charters was a member of the First Scientific Advisory Committee of the BRL, which would guide the scientific direction of vital research conducted during the war.

When the United States entered World War II, Dr. Charters was the Chief of the Aerodynamics Unit of BRL and was given the task of developing the first Aeroballistic Range which, with further developments in spark photography and measuring techniques, was completed in early 1944. The initial prototype range consisted of five spark stations and the final 300-ft long range consisted of twenty permanent spark stations. This unique facility contributed significantly to advancing the understanding of the aeroballistics of projectiles and is still in use today at the U.S. Army Research Laboratory (ARL) that subsequently incorporated BRL and it's facilities. In 1982, the Aerodynamic Range was designated a "National Mechanical Engineering Landmark" by the American Society of Mechanical Engineers. The range is recognized as the world's first, large-scale, fully instrumented ballistic range providing data on the aerodynamic characteristics of projectiles in free flight and became the model for similar installations worldwide. Dr. Charters was awarded a Commendation for Exceptional Civilian Service by Secretary of War Stimson for his contributions to the war effort.

In 1946, the rapid advancement of larger caliber projectiles required the development of a larger spark photography range and the advent of supersonic aerodynamics generated the need to test at velocities in the transonic region which bridges the subsonic and supersonic regions. The new facility would accommodate projectiles up to 203-mm and by 1950, the Transonic Range was completed and operational. The size of the building was 24-ft X 24-ft x 1000-ft and the facility is also still in use today at ARL. Dr. Charters was instrumental in the development of these two unique research facilities and the research conducted in these two facilities.

In 1951, Dr. Charters left BRL to become Chief of the Hypervelocity Ballistics Range Branch of the National Aeronautics and Space Administration's Ames Research Center. The primary research of his team involved the development of a light gas gun for tests of reentry vehicles and components of high velocity missile components. The development of the tapered "accelerated reservoir" concept in the pump section of the light gas gun in his Branch allowed the launching of fragile aerodynamic models eventually to 8 km/s. This design is used in most light gas gun designs today. Dr. Charter was instrumental in the development of early hypervelocity guns and these early hypervelocity impact experiments contributed significantly to understanding planetary impact phenomena and the correct interpretation of lunar and planetary imagery for the soon to come space exploration program.

In 1961, after 10 years at NASA Ames, Dr. Charters joined the General Motors Defense Research Laboratory in Santa Barbara, CA. where he designed and built the "GM gun", the largest two-stage light-gas gun of its time. This gun was capable of launching masses of several hundred grams to velocities over 7 km/s. Nearly 40 years later, this gun is still one of the largest in the world and is still operational, now located at the University of Alabama in Huntsville.

He left GMDL in 1967, and consulted with numerous organizations concerning the design, construction and use of advanced high velocity guns. In 1974, he joined the Naval Weapons Center at China Lake where he was involved in numerous ballistics efforts, but probably made his most significant contributions in the area of the interior ballistics of liquid propellant guns.

In 1982, Dr. Charters returned to Santa Barbara, joining the General Research Corporation, and focused on terminal ballistics, especially at high impact velocities. During this period, Dr. Charters made significant contributions to understanding hypervelocity impact phenomena and played a leading role in investigating the potential of advanced high-velocity projectile concepts such as the segmented rod.

For his sustained leadership, innovation, technical excellence, and contributions to ballistics and hypervelocity science for over fifty years, Dr. Charters was awarded the first Distinguished Scientist Award by the Hypervelocity Impact Society in 1989. After retirement, he remained active in his field and was named a Senior Institute Fellow of the Institute for Advanced Technology of the University of Texas at Austin, Texas.