Auguste Piccard and Paul Kipfer Are the First to Enter the Stratosphere

Overview

On May 27, 1931, Auguste Piccard (1884-1963) and Paul Kipfer became the first men to safely ascend into the stratosphere, riding in a pressurized gondola borne beneath a balloon designed by Piccard. This ascent was the first of many, and unmanned flights in balloons of similar design continue to this day. In addition to setting the stage for manned and unmanned exploration of the atmosphere, it was also a precursor to manned exploration of the ocean depths, which also took place initially in a craft designed by Piccard.

Background

From the earliest of times man has envied the birds in their ability to fly. Stories and myths of human flight are among the earliest and most universal in human history, although the difficulties of flight kept man out of the skies for millennia.

The first human flight occurred in 1783, when two men flew over Paris, France, in a balloon designed and built by the Montgolfier brothers. They had been preceded into flight by a sheep, a rooster, and a duck that flew in an earlier Montgolfier balloon.

Balloons changed little over the next century, continuing to be filled with hot air, which rises because it is less dense than the colder air of the atmosphere. They saw military action as observation posts during the American Civil War, and Napoleon used them to observe enemy troop positions during his many wars. World War I saw the use of balloons for observations, too, as well as the extension of balloons into blimps and dirigibles.

In addition to their wartime roles, balloons were quickly pressed into service by scientists looking for a stable platform, indeed, any platform, for scientific studies at high altitudes. From the heights, balloons could look back at the Earth, taking photos for later study. In addition, balloons provided scientists the opportunity to obtain air samples and instrument readings at a variety of altitudes. The lowest region of atmosphere is called troposphere, and the stratosphere is the region right above the troposphere. Early balloons collected most of their data from the troposphere. A handful of balloons were able to loft instruments into the stratosphere, obtaining interesting scientific readings. Some of these readings were among the first to show the existence of cosmic rays, from which a number of important scientific discoveries were made.

In 1931, Swiss physicist Auguste Piccard and his colleague, Paul Kipfer, became the first humans to reach the stratosphere in Piccard's balloon, achieving an altitude of 51,762 feet (15,777 m). During this flight, in addition to making some scientific observations, Piccard and Kipfer were also able to demonstrate that Piccard's design worked. To allow people to survive in the stratosphere, Piccard designed the first pressurized gondola, intended to keep air pressure within the gondola at a comfortable level even in the rarefied upper atmosphere. Another Piccard innovation was to design a huge balloon that could lift the entire gondola while remaining only partially inflated. This let the gas within the balloon expand as it ascended, giving steadily increasing lift as the balloon rose.

The following year, Piccard broke his record with an ascent to nearly 55,000 feet (16,764 m), and within a few years, others had risen to nearly 61,000 feet (18,593 m). Since then, manned balloons have risen to over 113,000 feet (34,442 m), although high-altitude research for its own sake has largely ended. Recent record-breaking balloon flights, including crossings of the Atlantic and Pacific Oceans and the 1999 circumnavigation of the Earth, have all taken place, at least in part, in pressurized gondolas riding beneath balloons in the stratosphere.

Impact

The most immediate impact of Piccard's flight was to show that people could survive in the stratosphere. An earlier high-altitude balloonist, American Hawthorne Gray, had died in the 1920s because he lost consciousness from a lack of oxygen at great heights (he rose to about 40,000 feet [12,192 m] in an open gondola). By designing and ascending in a pressurized gondola, Piccard showed that the stratosphere was survivable. This same principle was, in turn, used for all subsequent high-altitude aircraft, including passenger airliners. In addition, Piccard's flight opened the door for high-altitude research into cosmic rays, the properties of the atmosphere at such altitudes, and other areas of inquiry. Finally, recent record-setting balloon flights have all used balloons very similar in design to Piccard's, proving the soundness of his original design.

From an engineering standpoint, Piccard's gondola design was, if not revolutionary, at least very significant. Others had constructed vessels designed to withstand pressure differences, but none had been previously built solely for the purpose of travel at high altitudes. Other design features made the gondola even more innovative. For example, Piccard painted one half of the gondola white and the other black, and then added a motor to spin it at a slow rate to help control temperatures. Unfortunately, the gondola stuck with the black side facing the sun and it became uncomfortably warm inside. Another mishap, corrected on a second flight, resulted in a valve sticking shut that was to be used to vent gas when descending. Instead, Piccard and Kipfer had to wait until dark, when the gas cooled enough to lower them back to earth. However, these were not significant problems and should not detract from Piccard's overall sound design.

More revolutionary was the design of the balloon itself. This was the first balloon to be designed for high altitudes and low air pressures. Instead of being completely filled when it took off, the balloon looked nearly empty, with just a small bubble of hydrogen in the top and a long, slack balloon beneath. However, as the balloon ascended and atmospheric pressure dropped, the gas bubble at the top expanded, filling the entire envelope at altitude. Previous balloons, not designed to do this, could generate large pressure differentials between the atmosphere and the internal gas, threatening to rupture the envelope. Realizing this, Piccard purposely designed a balloon with enough lifting capacity to penetrate into the stratosphere and enough extra volume to accommodate the expansion of gas at high altitudes. This same basic design has been used in virtually all high-altitude balloons, manned and unmanned, for the past 70 years.

The other important impact of Piccard's flight was the scientific knowledge returned by him and those who followed. During his flights in 1930 and 1931, Piccard conducted research on cosmic rays, which had first been identified during earlier balloon flights at lower elevations. In future flights, many more cosmic ray experiments were conducted, providing a wealth of information about this then-unknown phenomenon. In fact, this method of data collection remains important to this day, and scientific researchers in many countries routinely send experiments aloft in high-altitude balloons to study cosmic rays, extrasolar x ray and ultraviolet sources, and to search for other astronomical information.

High-altitude balloon flights have also returned an impressive amount of meteorological data over the years. Balloons designed along the lines of Piccard's ascend into the upper atmosphere on an almost daily basis, gathering information that supplements satellite data and helps scientists better understand our atmosphere and weather. This information is used for weather forecasting as well as for scientific research.

The other significant impact resulting from this flight was the effect it had on subsequent high-altitude, manned balloon flights, including recent record-setting flights and attempts. For nearly three decades after Piccard and Kipfer's flight, many nations pursued manned, high-altitude balloon flight. Two of these programs were the U.S. Navy's Skyhook program and the U.S. Air Force's Manhigh program. These programs, designed to test pilots' abilities to function at high altitudes and, later, to test space suit designs, culminated in several ascents to over 100,000 feet (30,480 m). On one of these flights, on August 16, 1960, Air Force Captain Joseph Kittinger parachuted from over 102,000 feet (31,090 m) in what is still the highest jump ever made.

Interestingly enough, Piccard's design was also adapted to undersea exploration with little difficulty. While considering the problem of constructing a vehicle to explore the oceans' depths, Piccard settled on a design in which a metal sphere, packed with instruments, was suspended beneath a large metal envelope filled with gasoline. Because gasoline is less dense than water, this design was a nearly perfect analogue of his balloon design (gasoline was used because, unlike air, it compresses very little with increasing sea pressure, thus giving more constant buoyancy with changes in depth). In this vehicle, named the Trieste, Piccard's son Jacques descended to over 10,000 feet (3,048 m) in 1953. The Trieste later dove to the bottom of the Mariana Trench, the deepest spot on Earth.

P. ANDREW KARAM