Beginning the ascent in the Excelsior III gondola. As the balloon rose into the upper atmosphere, the helium gas inside expands and fills out the envelope of the balloon. The tests were carried out over the barren terrain of New Mexico.
The gondola on Manhigh II. This pressurized capsule was used by Major Simons on his 32-hour flight to 101,516 feet. With the pilot and equipment aboard, the total weight of the gondola was 1,648 pounds.
The instrument panel on the Manhigh gondola.
Balloons as Forerunners of Spaceflight and Exploration
For those watching carefully, World War II showed the first signs of the beginning of the space age. For the first time, a rocket with a warhead in its nosecone, the V-2, flew 60 miles (97 kilometers) up into space, crossed a continent, and bombed a major city—London. Combat aircraft climbed almost into the stratosphere, and the upper atmosphere became the higher ground the military wanted to conquer for strategic superiority.
The war had temporarily halted progress in balloon technology, but driven by the need to better understand the environment of the upper atmosphere, the military jumped into balloon research after the war. The problems to be faced by future military pilots, and, eventually, astronauts venturing into space, inspired the human high-altitude balloon flights of the 1950s and 1960s. Life-support systems, pressure garments, high-altitude parachutes, and other equipment all needed to be tested for the harsh environment of near space. The new plastic balloon technology made it possible to send human missions to the very edge of space to investigate aerospace medicine and the human factor.
In 1954, the Office of Naval Research (ONR) began the Strato-lab training program for manned balloon ascents to the upper atmosphere. Naval officers M. Lee Lewis and Malcolm Ross flew two training flights above 40,000 feet (12,192 meters) in 1956. These flights marked the first return of a manned U.S. balloon to the stratosphere since 1935.
In November, Ross and Lewis were ready for the first Strato-lab I flight in a pressurized gondola that was essentially a crewed space laboratory. For this flight, the ONR used the new thin plastic polyethylene, which made it economical to build very large balloons. On November 8, 1956, Ross and Lewis ascended to 76,000 feet (23,165 meters) under the first plastic 2,000,000-cubic-foot (56,634-cubic-meter) balloon, breaking Orvil A. Anderson and Albert W. Stevens' 1935 altitude record of 72,395 feet (22,066 meters).
At about the same time, the U.S. Air Force and the Department of Defense (DoD) began two projects to study high-altitude escape procedures. The Air Force's Manhigh project and the DoD's High-Dive Project were closely related efforts to develop high-altitude escape equipment and test re-entry vehicles from a balloon. In the High-Dive Project, which began in 1953, the DoD used live parachute jumps from balloon gondolas to address the problems of jumping from aircraft traveling at high speeds and miles above the surface of the Earth. It was already known that pilots flying at those altitudes needed to drop quickly immediately after leaving their aircraft to escape the inhospitable upper atmospheric layers before opening their parachutes. Then they needed to avoid the potentially fatal flat spin, which, while spinning faster and faster uncontrollably, could tear a man apart. This project developed the multistage parachute for this purpose. The 140 live drops culminated on December 11, 1959, when Captain J.W. Kittinger made the highest jump ever, 102,000 feet (31,090 meters) up, from the Excelsior II balloon. Kittinger landed safely on the ground after falling almost 20 miles (31 kilometers) thanks to the multistage chute. However, the chute was never adopted by military pilots.
Project Manhigh began in December 1955, to study the effects of high-altitude flight on humans in small capsules like those that would be flown in space. The Manhigh I capsule was about the size of a telephone booth, 8 feet by 3 feet (2.4 meters by 0.9 meter) at its widest point, and filled with instrument panels. Captain Kittinger also flew the first Manhigh balloon in 1957. Major David Simons flew Manhigh II for an altitude record. For the third flight, Manhigh III, the pilot was selected by a process that later would be used for astronaut selection. This included a claustrophobia test, pressure test, heat stress test, and a parachute jump. Lieutenant Clifton McClure was selected. During his 1958 flight, McClure endured 137 percent more heat than it was thought a body could tolerate while, at the same time, performing well enough to record ideas for improving the next flight as he descended in his balloon. David Simmons, who was the flight surgeon for McClure's flight, summed up what McClure taught them about human spaceflight: "An essential quality necessary to an astronaut would be stamina; not in a purely physical sense but in a psychophysiological sense: a combination of deep physical reserves plus the all-important emotional determination to use those reserves."
In October 1957, these flights to prepare humans for entering space took on new significance when the Russians launched the first satellite, Sputnik I. A few months before the Manhigh III flight, Congress passed the National Aeronautics and Space Act of 1958 establishing the National Aeronautics and Space Administration (NASA) as the successor to the National Advisory Committee for Aeronautics (NACA), which had included Orville Wright on its first advisory board. The space race was on.
Otto Winzen, who engineered the polyethylene balloons for many of the record-breaking flights of the 1950s, recognized that manned balloon flight was the logical predecessor to human spaceflight. He observed in 1958: "It is now generally recognized in scientific circles that the manned balloon capsule is the prototype of the manned space cabin. It serves not only for the study of the human factors of space flight, but for the selection and training of space pilots and as a test bed for the multitude of accessories and components which will eventually go into the construction of the sealed cabin will carry the first man into space."
On May 4, 1961, the Navy launched the final Strato-lab V from the deck of the aircraft carrier Antietam. Aircraft carriers make excellent launch sites, since they can match winds up to 30 miles per hour (48 kilometers per hour) and reduce the relative force across the flight deck to the equivalent of a dead calm. Three weeks before the flight, Yuri Gagarin had become the first man in space. One day after the flight, Alan Shepard was launched on America's first suborbital flight.
At a volume of 10 million cubic feet (283,169 cubic meters), Strato-lab V was the largest human-piloted balloon ever flown and set an altitude record that still stands—113,740 feet (34,668 meters). The pilots wore suits being tested for the Mercury astronauts. Lieutenant Commander Victor Prather drowned in his heavy suit when he slipped from the rescue helicopter harness.
With astronauts and cosmonauts orbiting the Earth in the 1960s, the second era of human high-altitude balloon ascents drew to a close. The Man-High and High-Dive (Excelsior) projects and Strato-lab had helped pave the way for humans to enter space.