Balloon Reconnaissance, History
Balloon Reconnaissance, History
█ JUDSON KNIGHT
balloons would increasingly serve fighting forces both for reconnaissance—particularly in the American Civil War—and later as bombers. The latter application would reach its apex with the German airships of World War I, a conflict in which the airplane proved itself a vastly superior instrument of aerial combat. Thereafter, the principal nation using balloons for surveillance was not Germany, but the United States, which employed them in the Second World War. American use of surveillance balloons and blimps continued even into the Cold War and the early twenty-first century war on drugs and homeland defense efforts.
The Principle of Buoyancy
Balloons and airplanes both rise into air, but by very different means. An airplane flies accordance to aerodynamic principles involving the relative pressure and speed of fluids (air and other gases are considered fluids in the terms of physics), and its lift depends heavily on the design of the wing's leading edge—a design borrowed from that which nature has given to the bird's wing. A balloon, on the other hand, rises according to the principal of buoyancy discovered by the Greek physicist and mathematician Archimedes (c. 287–212 b.c.)
According to Archimedes's principle, the buoyant force of an object immersed in fluid is equal to the weight of the fluid displaced by the object. This explains how a metal aircraft carrier weighing thousands of tons can float. If all the metal were crushed into a ball, it would sink to the bottom of the ocean, but when designed properly, the area inside the hull weighs less than the water it displaces. Similarly, the gases inside the envelope of a balloon must weigh less than the air around them.
Gases for buoyancy. There are three gases practical for use in balloons: hydrogen, helium, and heated air. Hydrogen would be ideal, except for the fact that it is extremely flammable, and helium, which was not discovered in elemental form until the 1860s, is extremely expensive to produce. On the other hand, heated air requires only a reliable heating source.
As French chemist J. A. C. Charles, an early balloon enthusiast, recognized in his famous law of gases, heating a gas increases its volume; thus, the air molecules inside the envelope of a balloon tend to spread apart, reducing the density of the air inside and making the craft buoyant. Ironically, Charles introduced the hydrogen balloon, which would dominate until the 1937 explosion of the Hindenburg. Since that time, most balloons have used heated air.
From the late eighteenth century to the U.S. Civil War (1783–1863). French brothers Joseph-Michel and Jacques-Etienne Montgolfier launched the first balloon on June 5, 1783. Later that year, the Montgolfiers sent up the first balloon crew—a sheep, a rooster, and a duck—and on November 21, Jean-François Pilatre de Rozier became the first human being to ascend in a balloon.
The first army air corps was born in revolutionary France in 1794, when a balloon contingent was established for reconnaissance purposes. The French used balloon reconnaissance extensively in the Napoleonic wars, and by the mid-nineteenth century, Britain, Russia, Austria, and Denmark were using balloons for military purposes.
In 1849, the Austrians undertook the first aerial bombardment campaign, using 200 unpiloted hot-air balloons against the Venetians. The effort proved disastrous when winds blew the balloons, whose explosives were set on timers, back to the Austrian side.
Balloons in the early United States. Whereas the Austrians' experience illustrated the problematic nature of balloons as bombers, the American experience in the Civil War showed that balloons had great potential for reconnaissance and purposes other than combat. For several decades, visionary military leaders had called for the use of balloons in warfare. During the Seminole War in Florida (1835–1842), Col. John Sherburne tried unsuccessfully to gain War Department support for a plan to use balloons for spotting Seminole campfires at night. A decade later, in the Mexican War, John Wise, later dubbed "the Father of American Aeronautics," proposed a balloon bombing campaign against the city of Veracruz, although the War Department ignored his proposal.
During the Civil War, Wise was one of several who proposed the use of balloon reconnaissance by the Union, but by far the most successful promoter of balloon reconnaissance was Thaddeus Lowe. While attempting unsuccessfully to cross the Atlantic by balloon, Lowe had found himself behind Confederate lines at the outset of the war, in April 1861. Having observed some military activity, Lowe offered his services to Union leadership, and proved to be the only balloonist the Union seriously considered. On June 17, 1861, Lowe and a telegraph officer ascended 500 feet (152 m) above the Columbia Armory in Washington, with telegraph lines running along the rigging wires and connecting them to the War Department and White House. Lowe's efforts won the support of President Abraham Lincoln, and over the next two years, the Union Army became host to one of the war's great experiments in technology and intelligence.
The Union balloon corps. During the winter of 1861–1862, Lowe gathered around himself an aeronautic crew that included two other ballooning pioneers, brothers Ezra and James Allen. They developed a system of signals from the ground to the air, and a method for getting balloons aloft while avoiding trees. They also found an effective means of transporting balloons, primarily aboard barges. While aloft, aeronauts, sometimes accompanied by military observers, would study details ranging from dust clouds to campfires, counting or if necessary merely estimating the number of enemy troops they saw. With a telescope, they could see as far as 30 miles (48 km) on a clear day.
The Confederates' many attempts to shoot down Lowe's balloons, which earned him the title "most shot-at man in the war," illustrated the effect the balloons had on morale. Years later, Confederate artillery officer E. P. Alexander said, "I never understood why the enemy abandoned the use of military balloons.… Even if the observers never saw anything, they would have been worth all they cost for the annoyance and delays they caused us in trying to keep our movement out of sight." The Southern states attempted to field their own balloons, but in this as in other areas, they lacked the technological means to effectively challenge the North. They finally did send up a balloon, made from silk dresses, but the Union promptly captured it.
Although Lowe's corps had the technological advantage over the enemy, the Union ballooning effort was doomed. Most Union generals failed to see the balloon's usefulness for a reconnaissance, and the fact that Lowe and his crew were civilians only added to the War Department view of them as outsiders. Lowe resigned in April 1863, and although the Allen brothers kept the balloons aloft for a few months, the corps had faded away by that summer. One of their last intelligence reports was of Confederate troops moving from Fredericksburg, Virginia, toward the Blue Ridge Mountains, the opening movements of a campaign that would lead to the decisive battle at Gettysburg, Pennsylvania.
From the Franco-Prussian War to World War I (1870–1918)
Balloons again proved their effectiveness for the French during the siege of Paris in 1870, when 66 balloons managed to transport 102 people and more than 2 million pieces of mail past the Germans. Impressed, the Germans formed their own balloon corps in 1884, and the Austrians in 1893. Russia opened a school of aeronautic training outside St. Petersburg. Britain, meanwhile, began military balloon training in 1880.
Still, the experience of the French in 1870 illustrated the limits of balloons. First, they could not be steered, and could only go with the wind. Second, the Prussians were rumored to have developed anti-aircraft guns that could shoot them down—which, while not true at the time, boded ill for low-flying craft.
Rise of the airship. By that time, a new variation on the oldfashioned envelope-and-gondola balloon had begun to show promise. This was the airship, an idea whose origins dated back to the Montgolfiers' era. Around the same time as the first balloon launches, another French designer, Jean-Baptiste-Marie Meusnier, began experimenting with a more streamlined, maneuverable model.
It was more than a century before Meusnier's idea became a reality. In 1898, Alberto Santos-Dumont of Brazil combined a balloon with a propeller powered by an internal-combustion engine. Although these men more clearly qualify as the fathers of the airship, they were to be eclipsed in history by a figure whose name became a synonym for it: Germany's Count Ferdinand von Zeppelin.
The Zeppelin. Zeppelin created a lightweight structure of aluminum girders and rings that made it possible for an airship to remain rigid under varying atmospheric conditions. The Zeppelins of World War I were legendary, as terrifying to the enemy as they were inspiring to Germans who sent them aloft.
At first, the German army failed to grasp their potential, so the navy began using them to scout British cruisers in the North Sea. At a time when aircraft were still in their infancy, and when the British fleet used light cruisers for reconnaissance at sea, the Zeppelin was both safer than an airplane and vastly more economical than a cruiser. In 1914, Zeppelin's company was turning out three airships a year; two years later, it was producing more than two a month.
Along the way, the use of Zeppelins as bombers overshadowed their role as reconnaissance craft. In 1915—fully a quarter-century before the Nazis' more famous bombardment—the Germans launched the first air battle of Britain. Far beyond the actual physical damage the Zeppelins wrought was the psychological effect of the dark shapes appearing in the British sky. At 10,000 feet (3,048 m), they were too high for antiaircraft guns of the time to reach them, and therefore they rained terror at will.
Even so, Zeppelins were cumbersome, dangerous craft, and in the final analysis, they were not cost-effective either for reconnaissance or for bombing. By September, 1916, the British had at their disposal explosive bullets that, when fired from an airplane, could shoot Zeppelins from the sky. Even the psychological value of Zeppelins proved a double-edged sword: recruiting posters and anti-German propaganda made heavy use of the Zeppelin as a symbol of the enemy.
Balloons from the 1920s to the Present
For a few years after war's end, airships constituted the luxury liners of the skies, but the Hindenburg crash signaled the end of relatively widespread airship transport. In the meantime, the U.S. Navy had taken an interest in airships, several of which were built for it by the Goodyear Tire and Rubber Company during the 1920s and early 1930s. After several mishaps involving rigid airships, the navy switched entirely to nonrigid airships, or blimps.
During World War II, the U.S. Navy was to be the only fighting force on either side to use airships. After the attack on Pearl Harbor, Congress authorized the construction of some 200 airships, which the navy used for photographic reconnaissance, scouting, minesweeping, antisubmarine patrols, search and rescue, and escorting convoys. Some 89,000 ships were escorted by airships during the war, and not a single one was lost. Although they were slow compared to airplanes, balloons could stay aloft for as much 60 hours, a decided advantage in an era before in-flight refueling.
Non-reconnaissance uses of balloons during the war included their employment by the British as protection against bombers, which had to fly over them to avoid their mooring wires, thus placing the Luftwaffe further from their targets and impairing accuracy. The Japanese employed some 1,000 "Fu-Go Weapons," or balloons equipped with bombs, which they sent eastward across the Pacific. These landed in some 16 U.S. states, as well as in Alaska, Canada, and Mexico. They killed only six civilians—a mother and her five children in Lakeview, Oregon, in May 1945—and the fact that the U.S. media agreed not to report news of the bombings greatly blunted their potential psychological effect.
The Cold War: Project GENETRIX. By far, the most significant use of balloon reconnaissance during the Cold War was Project GENETRIX. The program had its origins in a 1951 study by the RAND corporation, and in December 1955, President Dwight D. Eisenhower gave approval for the U.S. Air Force to launch 516 camera-carrying balloons over Eastern Europe, the Soviet Union, and the People's Republic of China.
GENETRIX proved a disaster in several regards. Only 34 balloons—about 7% of the total—survived and produced usable, useful images. Worse than the poor return ratio was the public-relations opportunity that the project provided to the communist bloc, which protested U.S. spying and used information on GENETRIX for propaganda purposes.
Central Intelligence Agency (CIA) officials called on the air force to halt GENETRIX, which it did in February 1956. At the time, the CIA was planning the launch of U-2 overflights, and they feared that GENETRIX would turn Eisenhower against the concept of overflights. Additionally, they were concerned that the program might negatively affect an effort by the Free Europe Committee, a CIA front based in West Germany, to drop propaganda leaflets over Eastern Europe.
The failure of GENETRIX concealed several successes. The images of the Soviet Union it did produce provided the best available record between World War II and the advent of the U-2 reconnaissance plane and later satellites. Additionally, the high-flying balloons, which averaged an altitude of 45,800 feet (13,960 m), provided data on wind currents that helped scientists determine the best flight paths for the U-2.
Finally, the most curious benefit of GENETRIX was the fact that a steel bar that secured the envelope, cameras, and ballasting equipment happened to measure 2.99 feet (91 cm)—exactly the same size as the wavelength of Soviet radar known as TOKEN to NATO (North Atlantic Treaty Organization) forces. Because it resonated when TOKEN pulses hit it, the bar helped NATO radar operators locate previously unknown radar installations. This, too, aided the U-2 project.
Balloon reconnaissance today. The navy, which had continued its balloon program until 1962, attempted to revive it in the 1980s, but Congress cut off all funding in 1989. Yet, the usefulness of balloons and blimps for surveillance is far from exhausted. Their virtual invisibility with regard to radar has reinvigorated interest in blimps on the part of the U.S. Department of Defense, which has discussed plans to use airships as radar platforms in a larger Strategic Air Initiative.
Meanwhile, the air force employs aerostats, or unmanned, aerodynamically shaped blimps tethered by a single cable, in its Tethered Aerostat Radar System, a counter-narcotics surveillance program along the U.S.-Mexico border. Aerostats offer a number of advantages, including enormous detection range and coverage. Typically occupying an altitude of about 15,000 feet (4,500 m), an aerostat can cover 185 square miles (480 sq km) and track smaller, lower-flying aircraft such as those used by drug smugglers. They can operate virtually without break at low cost, and need come down only for routine maintenance and severe weather. It is calculated that an aerostat can provide surveillance at a cost about 5% as great as that of an airplane. Kept aloft by helium, a highly non-reactive gas, they also have a considerably accident free record of operation.
█ FURTHER READING:
Brugioni, Dino A. From Balloons to Blackbirds: Reconnaissance, Surveillance, and Imagery Intelligence: How It Evolved. McLean, VA: Association of Former Intelligence Officers, 1993.
Evans, Charles M. The War of the Aeronauts: A History of Ballooning during the Civil War. Mechanicsburg, PA: Stackpole Books, 2002.
Lebow, Eileen F. A Grandstand Seat: The American Balloon Service in World War I. Westport, CT: Praeger, 1998.
Peebles, Curtis. The Moby Dick Project: Reconnaissance Balloons over Russia. Washington, D.C.: Smithsonian Institution Press, 1991.
Fanton, Ben. "View from above the Battlefield." America's Civil War 14, no. 4 (September 2001): 22–28.
Nahum, Hazi, and Sheike Marom. "Aerostat-Borne Systems for Defense and Homeland Security." Military Technology 26, no. 8 (August 2002): 102–108.
U.S. Centennial of Flight. <http://www.centennialofflight.gov> (March 13, 2003).
Civil War, Espionage and Intelligence
U-2 Spy Plane
World War I