Clifton McClure in the Manhigh III capsule. (credit: USAF)

50th anniversary of a forgotten space mission: Project Manhigh

by John C. Keel
Monday, October 27, 2008

Years before the first cosmonauts—even before NASA—there were men who touched the edge of space. These brave explorers were the pre-astronauts of Project Manhigh. October 8, 2008 marked the 50th anniversary of their last mission, Manhigh III. The solo pilot of Manhigh III was Clifton McClure, from Anderson, South Carolina.

By the 1950s, high-altitude balloons were capable of reaching higher than 99% of the Earth’s atmosphere. As a first step in sending man into space, the United States Air Force executed a series of manned high-altitude balloon missions in 1957–1958, known as Project Manhigh. These missions tested equipment such as space capsules, spacesuits, and telemetry and communication systems. Most of all, Manhigh first tested the ability of human beings to function in the harsh extremes of high altitude, where the blue sky ends and space begins.

Manhigh I and II were flown in June and August of 1957 by Joseph Kittinger and David Simons, respectively. For the third and final mission, new pilot requirements were expanded and refined, including psychological and stress testing as well as physical challenges such as the centrifuge. Having been the first to pass this rigorous gauntlet that would later be used to select the Mercury Seven, Clifton McClure was launched aboard Manhigh III on October 8, 1958.

In a sealed capsule filled with oxygen, nitrogen and helium, McClure soared to an altitude of 30,200 meters (99,700 feet) above the Tularosa Basin of New Mexico. He persevered through equipment failures that could have proven disastrous. His parachute came loose, but somehow he repacked it by hand while in the confined space capsule. Most significantly, the capsule’s cooling system failed, and temperature climbed, as it was beyond the radiation shielding of the atmosphere. Incredibly, McClure’s body temperature reached as high as 42.5ûC (108.5ûF), yet he remained conscious and recovered completely.

A graduate of Anderson High and Clemson, McClure also later became a member of the South Carolina Air National Guard. He flew the F-104 with the 157th Fighter Interceptor Squadron (now the 157th Fighter Squadron at McEntire JNGS, Eastover, SC). He was deployed to Spain during response to the 1962 crisis in Berlin. McClure passed away in January 2000. He was inducted into the International Space Hall of Fame in 2001.

Balloon missions continued briefly after Manhigh, including Excelsior and Stargazer, but all were soon overshadowed by NASA, and now they are all but forgotten. A few books have documented their feats, including The Pre-Astronauts: Manned Ballooning on the Edge of Space, by Craig Ryan, and Touching Space, by Gregory P. Kennedy. The Discovery Channel has aired a documentary on the pre-astronauts. A much-anticipated movie is also in progress to recount their amazing adventures.

Let us remember the remarkable, awe-inspiring achievements of McClure and the pre-astronauts. It was the pre-astronauts of Project Manhigh who were the first to see the curve of the Earth against the black void. As the space programs of the world prepare for the next stage, let us always remember those who have come before, for we pursue the most ancient dreams of mankind.

John C. Keel, MD, is a physical medicine and rehabilitation physician at Harvard Medical School. He is also a flight surgeon in the Air National Guard, in that same unit in South Carolina where his cousin, Clifton McClure, once flew. Dr. Keel can be reached at jckeel@gmail.com.

Home