Ballooning

I

Introduction

Ballooning, use of lighter-than-air craft known as balloons. Balloons consist of a large flexible bag containing either hot air or a gas that is lighter than air. The bag, known as an envelope, is made of varnished silk, rubber, or other suitable material. Piloted balloons carry one or more persons in a suspended gondola; unpiloted balloons are usually used for scientific research and carry instruments to measure and record a variety of physical phenomena.

Any gas that is lighter than air can be used to lift a balloon. Hydrogen, helium, methane, ammonia, natural gas, manufactured gas (gas made from soft coal or petroleum products), and heated air can and have been used to fly balloons. The earliest balloons were filled with hot air and often carried a brazier (metal container for burning coal or charcoal) to continuously heat the air. Modern balloons are usually filled with hydrogen or helium or air heated by a small gas burner. Helium has the great advantage of being nonflammable (difficult to burn or ignite), unlike hydrogen, which is flammable.

Balloons are used primarily for two purposes: sport or scientific research. Sport balloons mostly use hot air. They range from 10 to 20 m (33 to 66 ft) in size when the envelope or bag is inflated. Scientific balloons generally use hydrogen, helium, methane, or ammonia. They range in size from 30 to 200 m (100 to 660 ft) when fully inflated.

II

History of Ballooning

A

Early Balloons

The first practical hot-air balloon was invented in 1782 by two French brothers, Jacques Étienne and Joseph Michel Montgolfier, wealthy papermakers of Annonay, France. In a second balloon flight in June 1783 the two men sent up a paper-lined linen balloon that rose 1,800 m (6,000 ft). In August of the same year the French physicist, chemist, and aeronaut Jacques Alexandre César Charles released a balloon filled with hydrogen, which made a successful two-hour flight, covering 43 km (27 mi). In November the first piloted flight occurred when the French physicist Jean François Pilâtre de Rozier and his companion, the Marquis D’Arlandes, ascended in a hot-air balloon built by the Montgolfier brothers, from the Bois de Boulogne, a park in Paris. Rozier’s first ascent was in a balloon with ropes attached to the ground. Later he went up in a free balloon without ropes. In December the first piloted flight in a hydrogen-filled balloon was made from the Tuileries gardens in Paris.

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By the end of 1783 balloon mania had taken over in France and soon spread throughout the continent and England. Cities vied with each other to build the biggest or prettiest balloons and to fly higher and longer. Hot-air balloons were more maneuverable, but the hydrogen balloons flew for longer periods. In 1785 Rozier attempted to cross the English Channel in a balloon combining a hydrogen-filled bag above a hot-air balloon. The hydrogen caught fire, and Rozier and his copilot were killed. The balloon design, called a Roziere, was rarely used for the next 200 years but its revival made history, enabling balloonists to circumnavigate the globe for the first time.

In 1785 the French aeronaut Jean Pierre Blanchard, accompanied by John Jeffries, an American, made the first balloon crossing of the English Channel. Blanchard also made the first balloon ascent in North America, from Philadelphia, Pennsylvania, in 1793. The next century saw the use of balloons flourish for sport and celebration. In 1836 The Great Balloon of Nassau, with a capacity of 2,410 cu m (85,000 cu ft), sailed 800 km (500 mi) from London to Weilburg, Germany, in 18 hours.

B

Military Use of Balloons

During the Franco-Prussian War (1870-1871), balloons were used for military observation by the armies of both nations. The French statesman Léon Gambetta made a dramatic escape from the besieged city of Paris by balloon.

Armies in World War I (1914-1918) made extensive use of balloons, especially for military observation. The balloons were tethered (controlled by ropes) and used to observe enemy lines. They were quickly lowered when enemy aircraft were sighted. Allied and German pilots received medals for shooting down observation balloons.

During World War II (1939-1945) the barrage balloon (a large fabric balloon tethered to a steel cable) was used extensively to protect London from low-level air attacks. The barrage balloons were tethered in rows at altitudes up to 1,000 m (4,000 ft) to provide a barrier against enemy bombers attacking London. Also during World War II, Japan launched over 9,000 Fu-Go balloons in 1944 and 1945. These were 10-m (33-ft) laminated paper spheres inflated with hydrogen. A timing mechanism periodically dropped ballast (stabilizing heavy weights) to maintain the balloon near the jet stream (the wind that travels from west to east in the upper atmosphere). The balloons carried incendiary bombs and one high-explosive bomb. Only 10 percent of the balloons reached the West Coast of the United States, and most of these landed in the Northwest during the rainy season and caused little fire damage.

Balloons were also used during the Cold War. For a brief period the United States Air Force flew several hundred balloons equipped with cameras over the Soviet Union. A timer controlled the release of the cameras. Once released, the balloons rose rapidly and destroyed themselves in the atmosphere. The cameras descended by parachute over the Pacific Ocean, and U.S. Navy vessels recovered them. After the late 1960s high-flying aircraft and satellites replaced balloons in performing this reconnaissance.

C

Scientific Use of Balloons

In 1803 the first scientific balloon flight—to make measurements of electricity in the air—reached an altitude of 7,400 m (24,300 ft). A year later French chemist and physicist Joseph Louis Gay-Lussac made measurements of the composition of the air by using a balloon. Throughout the 19th century and into the 20th century, the balloon was the only vehicle available for atmospheric measurements. Scientists risked their lives flying to higher altitudes to conduct their experiments. In 1931 the Swiss physicist Auguste Piccard ascended into the stratosphere in a spherical, airtight, metal cabin suspended from a specially constructed hydrogen-filled balloon of 14,000 cu m (494,400 cu ft) capacity, reaching an altitude of 15,797 m (51,793 ft). The following year he reached 16,940 m (55,577 ft).

In 1935 two U.S. Army captains, Orvil Anderson and Albert William Stevens, ascended to 22,080 m (72,440 ft). The primary purpose of this flight was to determine how the makeup of the atmosphere changed with altitude by obtaining air samples in the stratosphere. In 1957 Major David Simons, a U.S. Air Force surgeon, ascended to about 31,110 m (about 102,000 ft), remaining in the air 32 hours. Simons’s flight was designed to study the physiological reactions of humans at high altitudes. In 1960 Captain Joseph Kittinger of the U.S. Air Force bailed out of a polyethylene plastic balloon at 31,354 m (102,867 ft), setting a new altitude record for balloon flight and a new record for parachute descent. In 1961 Malcolm Ross, a U.S. Navy commander, and Victor Prather set an altitude record of 34,679 m (113,776 ft).