US Air Force Major General. He became widely known as "the father of space medicine" and as "the man who paved the way for astronauts." As the Director of the US Aeromedical Research Laboratory, he applied his medical and aviation knowledge to the improvement of aircrew protection from temperature extremes and the lack of oxygen at high altitude. Born in De Smet, South Dakota he attended the University of Minnesota at Minneapolis/St. Paul, Minnesota but left after a year to enlist in the US Marine Corps during World War I and served from October 1918 to March 1919. After his discharge from the Marines, he entered the University of South Dakota at Vermillion, South Dakota and received his Bachelors Degree in 1921. He then enrolled at the University of Louisville in Louisville, Kentucky and received his Doctor of Medicine Degree in 1925. After enlisting the US Army Medical Corps Reserve in April 1925, he entered the School of Aviation Medicine at Brooks Field, Texas (now closed) that September and upon graduation in 1930, he was commissioned a first lieutenant in the Regular US Army Medical Corps and assigned to Fort Snelling, Minnesota. From September to December 1930 he studied at the US Army Medical School in Washington DC and graduated from the Medical Field Service School at Carlisle Barracks, Pennsylvania four months later. In 1931 he was attached to the US Army Air Corps and became assistant surgeon of the First Pursuit Group at Selfridges Field (now Selfridge Air National Guard Base), Michigan. In 1935 he was assigned to Wright Field (now Wright-Patterson Air Force Base), Ohio, to establish the Aero-Medical Laboratory, and served as its chief until July 1940. He received his Master of Science Degree in Medicine from the University of Cincinnati at Cincinnati, Ohio the same year, and a year later obtained his Master of Arts Degree from the University of Toronto, Toronto, Ontario, Canada. In 1941 he was assigned as military attaché at the American Embassy in London, England until he returned to the School of Aviation Medicine at Randolph Field (now Randolph Air Force Base, a part of Joint Base San Antonio), Texas, to establish a research laboratory, later re-designated the Research Section of the school. In the Summer of 1942 he returned to London, England and became assistant surgeon of the 8th Air Force and in January 1944, he became its surgeon. In 1945 he became surgeon for the Air Division in the office of Military Government for Germany (US), in Berlin, Germany. In 1946 he was promoted to the permanent rank of lieutenant colonel and returned to the School of Aviation Medicine at Randolph Field (now Randolph Air Force Base, a part of Joint Base San Antonio), Texas as Assistant Commandant, and that July he became its Commandant. In 1948 he was promoted to the temporary rank of brigadier general, then to the temporary rank of major general. In June 1949, he was assigned to Headquarters US Air Force in Washington DC as Deputy Surgeon General of the US Air Force. He was promoted to the permanent rank of colonel in October 1949 and the following month he became Surgeon General of the US Air Force. In October 1951 he was promoted to the permanent rank of brigadier general and three years later he was promoted to the rank of major general and assigned to Wiesbaden, Germany as Surgeon General of the US Air Forces in Europe and he retired in that position in September 1958 with 33 years of continuous military service. His military and foreign decorations and awards include the Air Force Distinguished Service Medal, the Legion of Merit with 1 oak leaf cluster, the World War I Victory Medal, the American Defense Service Medal with foreign service clasp, the American Campaign Medal, the European-African-Middle Eastern Campaign Medal, the World War II Victory Medal, the Army of Occupation Medal, the National Defense Service Medal, the French Croix de Guerre with palm, the Order of the British Empire, and the Belgian Croix de Guerre with palm, as well as a rated flight surgeon. His other notable awards include the Wellcome Award (1937), the Collier Award (1939), the John Jeffries Award (1941), the Honorary Fellow of American College of Healthcare Executives (1953), the Edward Warner Award (1981), and the National Aviation Hall of Fame (1998, posthumously). He was a fellow of the American Medical Association, Aero-Medical Association, Institute of Aeronautical Sciences, American College of Physicians, and the Royal Medical Society of London, England. His published works include "Principles and Practice of Aviation Medicine" (1939) and "Aerospace Medicine" (1961). In 1977 the Harry G. Armstrong Award for Scientific Excellence was created by the Air Force Aerospace Medical Research Laboratory. He died from heart disease at the age of 83. In 1985 the Aerospace Medical Research Laboratory at Wright-Patterson Air Force Base was renamed the Armstrong laboratory in his honor. The "Armstrong Limit," the altitude above which water boils at the temperature of the human body, is named after him.