In the mid-1950s, the US Air Force needed to know how humans could survive in an environment as hostile as space was assumed to be. To advance a space program, specific data were required to craft an intelligent plan for future spaceflights. Project Manhigh used stratospheric balloons to send men to the upper atmosphere, about 33 kilometers above Earth.
The beginnings of the space race were not easy. Little was known about space or its extreme conditions. Experiments and instrument launches, along with theoretical work, gave scientists an idea of what astronauts might face. In December 1955, the US Air Force launched Project Manhigh, a plan to learn firsthand the effects of cosmic rays and space on future astronauts. Rockets were still far off, so they used stratospheric balloons capable of exceeding 30,000 meters.
Project Manhigh
Dr. John P. Stapp, head of the Aeromedical Field Laboratory (AFL) of the Air Force Missile Development Center, approved the project. Dr. David G. Simons, also from the AFL, was chosen to lead it. The basic idea was simple: put a pilot inside a "can" full of sensors and telemetry equipment and send it as high as possible. Despite the apparent simplicity, the practical execution was anything but simple or risk-free. Winzen Research Inc., of Minneapolis, designed and built the capsule and balloon, planned the operation, and trained the pilots with help from Holloman Air Force Base personnel. Before manned flights, six test flights verified all system components.
At 6:23 on June 2, 1957, the first manned flight began. The capsule, launched from Fleming Field airport in South Saint Paul, Minnesota, carried Captain Kittinger. The 475th Air Base Squadron, based in Minneapolis, provided logistic support and a helicopter. The capsule consisted of a hermetically sealed aluminum cylinder, about 2.5 meters high and 1 meter in diameter, with hemispheres closing the ends. An aluminum tube structure supported the equipment (much of it disposable during flight), and six portholes provided a view of the outside.
The capsule hung from a parachute, which in turn was attached to the balloon via a suspension system that reduced oscillations. The pressure inside the cabin was equivalent to being on an 8,000-meter mountain, and a liquid oxygen converter allowed the pilot to breathe. A cooling system based on water evaporation kept the temperature at comfortable levels.
This first launch reached an altitude of 95,000 feet (about 28 kilometers), setting a new record for manned balloons. Unfortunately, an oxygen leak made the flight shorter than planned, spending only two hours at maximum altitude. When ground control told the pilot he had to end the flight early, Kittinger, who wanted to keep flying, replied in Morse code: "...come get me...". The capsule and its occupant landed safely at 12:57 near Indian Creek, Minnesota.
The second launch began at 22:00 CDT on August 18, 1957. The pilot was David G. Simons (who later became a famous doctor specializing in myofascial pain), and his balloon reached 102,000 feet (almost 30 km) in about two hours and 18 minutes. Although it was less than the planned 115,000 feet, it broke the world record again. In the early hours of August 20, the balloon encountered a storm front and descended to 70,000 feet. To avoid the clouds, he released ballast and passed over the storm.
After about 32 hours of flight, Simons landed safely in an alfalfa field in northeast South Dakota at 17:32 CDT. The pilot had spent, counting pre-launch and post-rescue hours, a total of 44 hours in the capsule. For this achievement, Simons received a certificate from the Fédération Aéronautique Internationale, and in 1962 described his flight experience in a book titled MANHIGH.
The Last Flight of Project Manhigh
The last flight of this series took place on October 8, 1958. The balloon was launched from Holloman Air Force Base, and inside the capsule was Lieutenant Clifton McClure, a materials engineer from South Carolina who had joined the Air Force in 1954. It is said that when he was already seated, he inadvertently pulled the cord of his chest parachute, which deployed over his legs. It was an essential parachute, intended to save his life if he needed to abandon the capsule, and it was folded in a very particular way. So much so that there was no other on the entire base.
Fearing that mission controllers would postpone or cancel the flight, McClure, despite having no parachute repacking training, proceeded to repack it in place, working seated in the cramped cabin. He had to make two attempts and finished just 20 minutes before launch. At 6:51 the balloon was launched and began to rise so fast that the pilot had to vent gas several times to reduce the ascent rate. Finally, he reached 100,000 feet.
The cooling system, this time based on dry ice, failed, and the temperature inside the capsule, especially near the pilot's head, became intolerable. Ground control, alerted by the data sent by the "ship", noticed that McClure had gone no less than eleven hours without consuming liquids and was becoming dehydrated. When he tried to drink, he found that his bottle had ruptured and he could not extract the water. He could only drink a few drops. This forced ground command to end the mission, and they told the pilot to release gas to descend.
An hour later, despite having opened the valve, he had only descended about 2,000 feet. The temperature kept rising, and there was fear the pilot would faint. If that happened, ground could order the balloon to release the capsule to descend with the main parachute. It would not be a soft landing, but McClure would certainly survive. Finally, at 16:00 the balloon began a pronounced descent at about 500 feet per minute, bringing relief to the team. But they still faced one more mishap: suddenly, communications with McClure were permanently cut off. The problem occurred when the pilot dropped a photometer, which jammed the foot button of the capsule's radio transmitter. McClure could receive instructions but could not send responses. When he manually turned on the flashing light of the location beacon at about 7 kilometers altitude, they finally knew he was conscious. He landed without problems at 18:42, in the middle of darkness, a few miles from the launch site.
McClure was immediately taken to the base hospital for rehydration, and it was confirmed that he had suffered no damage during the flight, despite the fact that the maximum temperature inside the capsule exceeded 42 degrees Celsius for hours. In 1960, Clifton McClure was awarded the Distinguished Flying Cross. After these three flights of Project Manhigh, Winzen conducted feasibility studies for a fourth mission, using a larger capsule and lasting 5 days, but no further experiments of this kind were ever carried out. Not many people know of this project, but the results obtained were crucial to developing the technology that later took man to the Moon.
