Dr. John Stapp: Pushing the Limits of Human Endurance

Dr. John Paul Stapp was a pioneer in aerospace medicine, known for his groundbreaking experiments that pushed the limits of human endurance. His primary focus was understanding how acceleration and deceleration affect the human body to enhance the safety of aircraft, spacecraft, and automobiles.

In October 1944, Stapp joined the U.S. Army Air Forces as a physician and became a qualified flight surgeon. By 1946, he was assigned to the Aero Medical Laboratory at Wright Field's training facility in Dayton, Ohio, where his interest in testing human tolerance took off.

Driven by the increasing speed and altitude of post-World War II aircraft, Stapp wanted to research human tolerance to G-forces, rapid spins, oxygen deprivation, and exposure to cosmic rays. This endeavor was partly sparked by witnessing ejection seat tests.

Stapp's initial experiments took place in early 1947 on a 2,000-foot track at Muroc Air Force Base (now Edwards). Northrop Aircraft created a sled with rockets to produce a maximum speed of around 200 miles per hour, and installed 45-foot-long hydraulic brakes at the end of the course. The sleds, which were code-named “Gee Whiz.”

Stapp himself frequently rode the sled, even suffering injuries during the experiments that included a fractured wrist. The sled’s breaks produced a deceleration of up to 35 Gs, or 35 times the force of gravity. Before the experiments, it was believed that 18 Gs would be fatal for humans.

Stapp relocated to Holloman Air Force Base in 1953. There, in collaboration with the Northrop Corporation, he developed the advanced Sonic Wind No. 1 sled, equipped with a propulsion section and a water brake system that used a scoop to stop the sled by digging into dams.

On March 19, 1954, Stapp, strapped into a jet pilot's seat replica, made his first ride on Sonic Wind No. 1. Six rockets propelled the sled to a speed of 421 mph, setting a land speed record.

Subsequently, more objectives, such as testing human tolerance to wind blasts, were integrated into the experiments. On August 20, 1954, the sled reached a remarkable speed of 502 mph, with Stapp exposed to the elements and surviving the ordeal.

Stapp's most notable run took place on December 10, 1954. With nine rockets behind him, he reached a speed of 632 mph in just five seconds. The 1.4-second deceleration subjected him to over 40 Gs. Emergency personnel had to remove him from the seat due to severe injuries, including burst blood vessels in his eyes, temporary blindness, cracked ribs, broken wrists, and circulatory and respiratory issues. His remarkable feat earned him the title of the "Fastest Man on Earth" and a spot on the cover of Time Magazine in September 1955.

Stapp soon shifted his focus to the Manhigh Project, collaborating with Dr. David Simons to study human endurance at the edge of space through high-altitude balloon flights. This research was crucial in ensuring astronauts could withstand the G-forces during launch and reentry and the rigors of space travel.

In 1957, Stapp and his team launched Simons to a record-breaking altitude of 101,000 feet in a pressurized gondola as part of Project Manhigh, lasting 32 hours. Simons was celebrated on the cover of Life magazine and hailed as "The First Space Man."

With the launch of Sputnik by the Soviet Union in 1957, space exploration became a priority for NASA, which took over research in this field. Stapp assisted NASA in selecting astronauts for Project Mercury, the United States' first manned space program.

Stapp returned to the Air Force to conduct his final high-altitude balloon experiment, Project Excelsior, with the aim of developing an ejection system for rocket-powered jets at high altitudes. On August 16, 1960, test pilot Joseph Kittinger, who had also worked on Project Manhigh, ascended to 102,800 feet in just 90 minutes, breaking records set by Simons in 1957. Kittinger's leap from the balloon resulted in the longest free fall and parachute jump in history, covering nearly 20 miles in just 13 minutes and 45 seconds.

Stapp's pioneering work laid the foundation for advancements in aerospace safety. He developed safety innovations, including the "side saddle" harness, designed to protect paratroopers during rough landings.

He later also developed a keen interest in the potential applications of his research in the realm of automobile safety and was a prominent advocate for the use of seat belts.

Dr. John Paul Stapp passed away on November 13, 1999, at the age of 89, leaving behind a profound legacy in aerospace medicine and safety.

Photo credits - NASA, Air Force Test Center History Office, U.S. Air Force, Air Force Research Laboratory, Department of Defense, DoD News Channel, Wright Air Development Division - Aerospace Medical Division