[2.0] Balloons In Peace & War 1900:1945

v2.2.0 / chapter 2 of 5 / 01 oct 17 / greg goebel

* In the early years of the 20th century, ballooning became a sport for the wealthy elite, with ballooning competitions making front-page headlines all over the world. Balloons would also become an important weapon in the First World War, being used for observation and, in the form of "barrage balloons", for anti-aircraft defense. In the years after the Great War, although sport ballooning declined, spectacular balloons would be built for daring flights into the stratosphere. In World War II, barrage balloons would again play a significant role, with both the British and the Japanese using balloons for offensive operations as well.

barrage balloon



* By the beginning of the 20th century, the focus of civilian ballooning had shifted from showmen such as Wise and Lowe to gentleman enthusiasts, who had the money to support what had become an expensive sport. "Aero clubs" for balloon enthusiasts were established in a number of nations and arranged balloon races and other ballooning events. In 1906, the Federation Aeronautique Internationale (FAI) was established in France to set standards and maintain records for ballooning and other aeronautical ventures.

In that same year, 1906, the first open international public balloon race, sponsored by James Gordon Bennett, the publisher of the NEW YORK HERALD, was performed in Paris. 16 gas balloons were entered, with the balloon envelope fixed by race rules to a capacity of 3,250 cubic meters (114,700 cubic feet). The event went beautifully, with the 12,500-franc prize won by a team of two US Army officers, Lieutenant Frank P. Lahm and Major Henry B. Hersey. When their balloon touched down in England, a witness said that "an earthquake could not have caused more excitement!" The annual Gordon Bennett Cup race became front-page news. It was hosted in the USA and a number of European countries.

In the meantime, although automated sonde balloons had taken over the task of high-altitude measurement, crewed high-altitude research flights did continue to an extent. Arthur Berson, who had set an altitude record in 1894, topped it in 1901, rising with his colleague Reinhard Suering to 10,825 meters (35,500 feet), but nobody saw much need to beat this record at the time.

The Austrian physicist Victor Hess did perform balloon flights in 1911:1912 that would win him the Nobel Prize in physics in 1936. He took an electroscope, a device to measure ionizing radiation, up in a balloon to up to 5,350 meters (17,500 feet) to determine the source of a mysterious background radiation that was plaguing scientific experiments. It had been thought the radiation was coming from the ground or air, but Hess's flights showed that it got stronger with altitude, and he concluded that it came from space. He had discovered what would later be called "cosmic rays", which still remain mysterious in some ways. The exercise did break new ground in ballooning, since for the first time a balloon had been used to perform significant observations of space, but Hess never came close to setting any sort of balloon record; he had no need to do so.

Charles Greely Abbott, the director of the US Smithsonian Astrophysical Observatory, followed in Hess's footsteps by performing flights in 1914 to observe solar radiation at high altitude. In August of that year, the First World War broke out. Sport ballooning and research flights were suspended for the duration.

* Balloons would play a significant role in the conflict, initially as observation platforms. In the 1890s, the Germans had introduced sausage-shaped aerostats, which they named "Drachens (Dragons)", with the shape helping to ensure that the balloon did not tend to spin and tumble around in the wind. The French later added triple tailfins to further improve stability. The invention of the telephone provided a convenient means of communication back down to the ground. Most of the world's major armies adopted such "sausage" balloons.

Observation balloons saw action in the Boer War and the Russo-Japanese War; they saw major use in the First World War. The static trench warfare of that conflict was an ideal environment for the observation balloon, and both the Germans and the Allies made extensive use of them, lofting them high behind their own lines to keep an eye on what was the other side was doing. Of course, balloons had company in the skies by that time, in the form of aircraft, and observation balloons made tempting targets for enemy fighters. "Balloon busting" required some nerve, however, because balloons were usually heavily shielded by a barrier of anti-aircraft guns, and any pilot who tried to take a pass at a balloon was likely to get an unfriendly reception.

Still, balloons were very vulnerable, particularly since they were filled with flammable hydrogen; the inert gas helium had been discovered a few decades before, but it was difficult to obtain. Balloon observers under attack could do little but bail out and trust to their parachutes for survival. The parachute pack wouldn't be invented until 1919, with parachutes stored in metal cones alongside the gondola that popped open when the observers jumped out. Ironically, while fighter pilots were "scored" on the number of enemy aircraft they shot down, balloon observers racked up the number of times they had to bail out; some survived five or more shootdowns. As aircraft improved, they took over the observation role from balloons, and the First World War was the last conflict to see major use of crewed observation aerostats.

WWI observation balloon

* The autonomous balloon also played a role in combat, in the form of the "barrage balloon", which was a finned, sausage-shaped aerostat that trailed heavy cables over critical target areas to discourage low-level air attacks. The British invented the scheme after the Germans began attacking London with twin-engine Gotha bombers in the spring of 1917.

The balloons were organized in triplets, with the three balloons linked together by 460 meter (1,500 foot) steel cables and raised to 2,150 to 3,000 meters (7,000 to 10,000 feet). The triplets were known as "aprons", and by June 1918 the British had deployed them in a screen to protect the northern and eastern approaches to London. The balloons were deployed for about a year. Although no Gotha was known to have been brought down by the balloons, they did force the intruders to stay high, which helped degrade their aim. The Germans regarded the balloons as very effective; in fact, since the flight ceiling of a Gotha was only 4,000 meters (13,000 feet), had the balloons been raised a bit higher, they would have blocked the bombers completely. With the Armistice in 1918, the balloons came down along the fronts.



* The Gordon Bennett Cup was resumed in 1920 to renewed public interest, though the 1923 races were a disaster. The race was launched from Brussels on 23 September from Brussels, Belgium, with 34 balloonists in 17 balloons. The weather was clearly foul, but the race went ahead anyway. By the time it was over, six balloons had been destroyed by lightning, wind, or high-altitude snow, with five balloonists dead and five more injured. That did not kill off the Gordon Bennett Cup races, but by that time they were gradually being eclipsed by aircraft racing, and when the races were once again suspended by war, in 1939 -- Poland was to be the host country but it was being overrun by the Nazis -- few paid much attention.

However, a number of spectacular high-altitude flights were performed in that era that captured public imagination. In 1927, a US Army balloonist named Hawthorne C. Gray decided to try to conduct balloon flights into the stratosphere, up to altitudes above 12.2 kilometers (40,000 feet), to determine how well a human could function under such conditions. He also hoped to break Arthur Berson's record.

Gray planned to make the ascent in an open gondola, wearing arctic gear and an oxygen breathing apparatus. His initial flight, from Bellville, Illinois, on 9 March 1927 was a failure, with Gray passing out at about 8.2 kilometers (27,000 feet). Gray modified his equipment and procedures, to try again on 4 May, actually reaching almost 13 kilometers (42,470 feet). Unfortunately, his descent was much too rapid and he couldn't slow it down no matter how much he threw overboard, and he was forced to bail out to leave the balloon to crash to earth, denying him an official record. He tried a third time, on 4 November 1927, but though he did reach an altitude of 13 kilometers (42,740 feet), he failed again, this time fatally. The next day, the gondola of his balloon was found in a tree in Tennessee. Gray was still inside, very dead; he'd run out of oxygen during the descent. He was posthumously awarded the Distinguished Flying Cross.

* Gray had exceeded the limits of what was practical with the equipment of the day. At the low atmospheric pressures found at high altitudes, it's not enough just to have a source of oxygen, since nitrogen will begin to form bubbles in the blood, causing the agonizing condition known as "the bends". To reach really high altitudes, balloonists would have to ride in a pressurized gondola or wear a pressure suit. The first option was easier to implement, and that was the approach taken by Gray's successors.

A Swiss physicist named Auguste Piccard wanted to perform high-altitude balloon flights to study cosmic rays, and designed a pressurized gondola to perform the flights. The gondola was a sphere with a diameter of 2.08 meters (6 feet 10 inches) and a weight of 136 kilograms (300 pounds). It could keep two passengers alive at high altitudes for up to ten hours, using bottled oxygen, along with a "scrubber" system to prevent buildup of carbon dioxide.

Piccard also addressed another problem of high altitude balloon flights, the tendency of the lifting gas to expand as air pressure decreased until the gas began to vent out of the balloon, limiting altitude. Piccard's solution was obvious in hindsight: to that time, balloons were fully inflated before takeoff, but he had an envelope made with a capacity of 14,170 cubic meters (500,000 cubic feet), five times bigger than the volume of gas needed to get the balloon off the ground, giving the gas plenty of room to expand. It gave the balloon the "teardrop" appearance associated with modern high altitude balloons, or at least the appearance they have at launch. At high altitudes, the expansion of the gas gave Piccard's balloon a more traditional, near-spherical appearance.

Piccard and his assistant Paul Kipfer lifted off from Augsburg, Germany, on 27 May 1931. They achieved a record altitude of 15,785 meters (51,775 feet), but as happens with any "maiden voyage" of a new technology, the flight was full of bugs, some of them dangerous. Air leaks had to be plugged. The gondola was painted half black and half white and was to be rotated to maintain temperature, but the motor that was supposed to drive the rotation failed and the gondola overheated. Worst of all, the valve line became twisted and there was no way to vent the balloon. All the two balloonists could do was wait for the Sun to go down and the hydrogen to cool -- and pray they didn't run out of oxygen before then. They did land that night, ending up stranded on a glacier and enduring bitter cold before sunrise. The gondola sat on the glacier for a year before it was finally recovered by a museum in Brussels; it had acquired a fair amount of graffiti in the meantime.

Piccard's wife was unhappy at her husband's misadventure and he swore he wouldn't do it again, but he did make a second flight, from Zurich, Switzerland, on 18 August 1932, accompanied by a colleague, physicist Max Cosyns. The flight was another record-breaker, reaching 16,200 meters (53,150 feet). Piccard had redesigned the valve line and there were no problems with coming back down, but this time the gondola was painted all white, and the two balloonists had to endure freezing cold.

Piccard had finally had enough, and decided to give up on high-altitude flights. Whatever relief his wife felt at this was short-lived, however, because Piccard then decided to design the "bathyscaphe", a sort of underwater balloon filled with gasoline that was designed to descend to the very bottom of the ocean. Piccard would break new records in the opposite direction with his bathyscape after World War II.

* To Auguste Piccard, high altitude flights were merely a means to an end, not an end in themselves, and he had no particular interest in setting altitude records. However, his flights made headlines and he ended up becoming a celebrity almost in spite of himself. He also touched off a competition between the Soviet Union and the United States that would be echoed by the "Space Race" between the two nations a few decades later.

The Soviets began the race in September 1933, with Georgi Prokofiev, Ernst Bernbaum, and Konstantin Godunov performing an ascent to 17,900 meters (58,700 feet) in the STRATOSTAT USSR. It was the biggest balloon ever built to that time, with an envelope 24,940 cubic meters (880,000 cubic feet) in volume, and an electrically-actuated ballast dump system.

Although Auguste Piccard had given up on high altitude ballooning, his twin brother Jean Piccard picked up the baton, going to the USA to build a high-altitude balloon, named A CENTURY OF PROGRESS for the world exposition then in progress in Chicago. On 20 November 1933 two Americans, US Navy Lieutenant Commander Thomas Settle and US Marine Corps Major Chester Fordney, lifted off in the balloon from Akron, Ohio, to reach a new record altitude of 18,665 meters (61,221 feet), breaking the Soviet record. Along with the altitude record, the flight performed significant scientific observations, with the experimental team backing the mission including two Nobel prize winning physicists, Arthur Holly Compton and Robert Millikan. The instruments carried on the flight included a cosmic-ray instrument that would hopefully determine the source of cosmic rays, as well as an infrared camera and spectroscope for studies of the ozone layer, an atmospheric sampling system, and other gear. The cosmic-ray instrument, incidentally, showed that cosmic rays came from no particular part of the sky, deepening their mystery.

Prokofiev, Bernbaum, and Godunov tried to leapfrog the American record using a new, improved balloon on 30 January 1934. They reached 21,950 meters (72,000 feet), but the gondola broke free during the descent, and the three balloonists were killed.

The Americans were not done with the exercise, with the US Army Air Corps and the private National Geographic Society developing the next balloon of record size, the EXPLORER I, with a volume of 84,950 cubic meters (3 million cubic feet), three times the volume of the STRATOSTAT USSR. On 27 July 1934, Major William Kepner, Captain Albert Stevens, and Captain Orvil Anderson, all of the US Army, lifted off from Rapid City, South Dakota, in the EXPLORER. The three Americans were trying to reach 22,865 meters (75,000 feet) -- but when they reached 18,300 meters (60,000 feet) the rubberized cloth envelope began to tear open, and the balloon began to fall with increasing speed.

They were broadcasting live over a national radio network and the cliffhanger was heard by millions. The balloon's envelope continued to shred and then, at about 1,830 meters (6,000 feet), just as the crew was preparing to bail out, the hydrogen exploded, no doubt ignited by a static spark. Anderson got out quickly, but Stevens had to struggle with the rushing wind; he finally got out, and Kepner followed him. All the crew survived with no serious injury. Later in 1934, Jean Piccard and his wife Jeannette took the rebuilt CENTURY OF PROGRESS on a flight from Dearborn, Michigan, to an altitude of 17,380 meters (57,000 feet).

EXPLORER II gondola at the Smithsonian

By mid-1935, the Soviets were back performing high-altitude research flights, though they were no longer focusing on setting records. The Americans were still after records, however, and 10 November 1935, Stevens and Anderson tried again in the EXPLORER II, which was filled with helium instead of hydrogen; some sources claim it was the first large helium balloon. Helium was more expensive than hydrogen and had about 7% less lifting power, but it did not burn. The crew of EXPLORER II performed scientific observations from an altitude of 22,070 meters (72,395 feet), establishing yet another record.

That was the end of the stratosphere balloon flights for the time being. By 1936, war was becoming increasingly likely, with nations beginning to prepare for combat. The high-altitude balloon competition did provide useful experience in building pressurized enclosures for high-altitude flight.

* Jean Piccard remained interested in finding cheaper and lighter materials for balloon envelopes, EXPLORER II had taken balloonists about as far as they could go with rubberized cloth envelopes, because as such envelopes grew bigger, their weight grew faster than their lifting power. Piccard worked with physicist John Ackerman of the University of Minnesota to fabricate small balloons made of latex -- natural rubber -- or cellophane, and performed flights with clusters of such balloons. Piccard performed an experimental low-altitude flight in the PLEIADES on 18 July 1937, lofted into the sky on 92 latex balloons.

Neither latex nor cellophane were particularly good materials for balloon envelopes, but Piccard still felt that plastics were the way of the future. World War II interrupted serious work in high-altitude ballooning and the next steps had to wait until the end of the conflict.



* The British had found barrage balloons effective during World War I and came back to them with a vengeance during World War II, deploying them in the thousands to protect cities and key installations as an integrated part of the nation's air-defense system. Work on the program began in 1936 as war jitters increased, with the Committee for Imperial Defense authorizing the deployment of a barrage of 450 balloons to protect London. The balloons were then gradually deployed over other critical targets, such as harbors or river estuaries. Although there were some problems in ramping up production, by the end of 1940 over 2,000 balloons were floating over Britain, with roughly that number remaining in service until the end of the conflict.

The balloons were sent up individually, not in triplets as in World War I. They were under control of the British Royal Air Force (RAF) "Balloon Command", which had 33,000 personnel at its peak. As forces and materiel were built up in England for the invasion of France, the joke went around that if the barrage balloons were all cut loose, the island would sink.

The balloons were credited with a number of "kills" during the Battle of Britain -- though as in World War I, their main purpose was simply to present a hazard to aircraft attempting to perform precision low-level attacks. They also helped frustrate aerial mine-laying. The Germans found a screen of balloons deployed at Dover annoying enough to try to clear it away in August 1940, but that proved hazardous since the balloons were associated with anti-aircraft gun batteries. After suffering a number of losses and finding out that balloons shot out of the sky were quickly replaced, the Germans gave up the effort: it was far less expensive for the British to replace balloons than it was for the Germans to replace aircraft and pilots.

The primary enemy of barrage balloons was the wind, since the balloons could be blown off their moorings in storms. Losing a balloon in a storm was troublesome, and to make such losses even more troublesome, the heavy cables trailed by the balloons could also cause secondary damage. In addition, the presence of the balloons served to mark a target they were supposed to protect, but predominantly overcast British weather tended to minimize this problem, and the balloons certainly discouraged intruders from mucking about in low clouds.

Only weeks after the landings in Normandy in June 1944, as the troops were trying break out of the Normandy beachhead, the Germans were launching large numbers of "V-1 flying bombs", primitive jet-propelled cruise missiles, at London and other targets. The V-1s came in low and fast, and the British set up a screen of 1,750 barrage balloons as a final line of defense to back up fighters and radar-directed anti-aircraft guns.

barrage balloons for D-Day

The Americans used barrage balloons during the war as well. By August 1942, over 430 had been deployed at critical targets on the US West Coast to guard against a Japanese sneak attacks, and US Army balloon units brought them ashore during amphibious operations. Barrage balloons accompanied the Allied landings in Africa, Italy, and particularly Normandy, where 4,000 balloons littered the skies to protect the landing beaches from low-level attack. Barrage balloons were also towed around at sea before the Normandy invasion as part of a deception exercise intended to convince German radar operators that they were actually viewing a huge landing force.

In addition, the Germans and the Soviets deployed barrage balloons. Some schemes were devised in which barrage balloons were strung with mines on their cables to increase their lethality to aircraft. The evidence suggests the idea didn't work very well.

* Along with extensive use of barrage balloons, the British conducted a large-scale offensive balloon program. In 1937, in anticipation of war and the mass deployment of barrage balloons, the British Air Ministry conducted a study to determine how much damage a barrage balloon might do if it came loose and dragged its steel cables across the countryside to short out power lines. The result of the study was that a balloon could shut down power for a minimum of six hours.

The study was strictly a civil-defense exercise, with little or no thought given to use of balloons as offensive weapons. Early in the war, however, a plan was cooked up to attack the Germans with balloons carrying high-explosive or incendiary bombs. The bombs would carry a transponder system to allow them to be tracked by radio direction-finding equipment; they would also carry a remote-controlled release mechanism to permit the munitions to be dropped where they would hopefully do the most harm. In the spring of 1940, the Germans invaded the Low Countries and France, quickly conquering them, and then began to bomb Britain by air. The balloon bombing scheme was shelved for the time being, but it wasn't forgotten.

On the night of 17:18 September 1940, a gale swept across Western Europe, tearing barrage balloons from their moorings. The balloons caused considerable havoc in Nazi-occupied Denmark and neutral Sweden, knocking out power and even toppling the broadcast tower of the Swedish international radio service. British Prime Minister Winston Churchill, who was fond of "thinking out of the box", suggested that if balloons could do this kind of damage without trying, they might do a lot more damage if deliberately sent over Germany to cause harm.

The Air Ministry examined the idea and rejected it, coming to the conclusion that the Germans would retaliate in kind, and that the British power grid was much more vulnerable to such attacks than the German power grid. There was also a perception that an offensive balloon campaign was a distraction from more important military programs. However, an Admiralty Board liked the idea, asserting that balloons would cause real confusion because they attacked so silently, and that the effort would not cost much in material or British lives.

The Admiralty envisioned the balloons carrying two or three incendiary munitions. Germany had large evergreen forests that could be ignited by such munitions, and dealing with the fire hazard would be a drain on German resources. Britain was less vulnerable to retaliation, since the UK's forests were small and mostly deciduous, losing their leaves in the winter and making them less prone to fire. Besides, at operating altitudes, the winds went from Britain to Germany about 55% of the time, but only blew 38% of the time in the reverse direction.

The Air Ministry came back with their original arguments, saying that the balloon program would be too expensive and ineffective, and added that the balloons would be a hazard to British aircraft. The Admiralty responded that the program was very cheap; the resources needed, such as hydrogen gas, were in excess supply; and procedures could be implemented to reduce the risk to planes and pilots. The clincher for the Admiralty's case was an analysis that showed the British power grid could generally withstand short circuits caused by German balloons trailing wires, while the German power grid would suffer badly from similar attacks by British balloons.

The program, codenamed OUTWARD, was approved in September 1941. The first OUTWARD launches were performed on 20 March 1942, the launches being generally being performed by "Wrens", personnel of the Women's Royal Navy Service (WRNS). Reports trickled back of balloon sightings and public warnings in Axis-occupied territory and operations ramped up, with a second launch site set up in July 1942. Arrangements were made with the RAF to ensure that balloons weren't launched when they could interfere with RAF bombing raids. Launches always had to be performed in daylight, with two hours advance notice given to the RAF.

The balloon campaign was scaled back in the spring of 1944 lest it interfere with the planned Normandy landings, and was finally halted completely on 4 September 1944, since by that time Allied forces were in the "line of fire" of the balloon attacks. Almost 100,000 balloons had been launched during OUTWARD; they were about 3 to 3.5 meters (10 to 12 feet) in diameter, with a little less than half of the balloons trailing wires and a little more than half carrying an incendiary device.

The wires were about 90 meters (100 yards) long, and there appear to have been several different incendiary payloads -- "socks" filled with straw and fitted an igniter, a metal can of napalm with an igniter, and a can that popped open to drop a glass bottle full of an incendiary mix that apparently lit up when the bottle smashed onto the ground. It also seems that some of the balloons carried radio trackers to allow the motion of the balloon stream to be followed. The Wrens generally found their work entertaining, though they had to take care not to get a leg tangled in a trailing wire when releasing a balloon. They were inclined to scribble graffiti on them when they could get away with it, such as DEATH TO ALL GERMANS, BALLS TO HITLER, and TAKE THIS YOU BASTARDS!

It is hard to say that OUTWARD had much to do with winning the war, but analysis showed that it was definitely cost-effective. It was implemented with less than 300 personnel, the bulk of them Wrens, not men needed for frontline service, and cost about 220,000 pounds in all. The most spectacular success achieved by OUTWARD was on 12 July 1942, when a balloon shorted out power lines near Leipzig, causing a fire in a power station that then burned to the ground, with damages estimated at a million pounds. That was several times more than the British expended on OUTWARD from the first to the last.

The balloons were of course indiscriminate, and in some cases blew back on British soil, shutting down a railway at one time, and also starting a fire in a village in the Midlands. Since OUTWARD was secret, the fire was attributed in the British press to HITLER'S FIENDISH NEW WEAPON! They caused more damage in neutral Switzerland and Sweden, with a wayward balloon shorting out a Swedish rail lighting system on the night of 19:20 January 1944, leading to a train collision. There were diplomatic protests, but if the balloons were a nuisance to neutrals, they were likely an infuriating source of aggravation for the Germans -- who could only swear at the "damned devious Tommies" as balloons floated silently across the countryside, leaving a trail of damage behind them.



* Operation OUTWARD remains somewhat obscure, being overshadowed in the historical record by Japanese attempts to attack the continental United States with balloons. From the late fall of 1944 through the early spring of 1945, the Japanese launched thousands of bomb-carrying balloons to float across the Pacific and drop their loads in the US.

The Imperial Japanese Army (IJA) had performed experiments with balloons from the late 1920s into the late 1930s, evaluating them for delivery of propaganda leaflets or even dropping troops. Nothing came of these efforts at the time, and an exercise in using small balloons towing grenades on wires to disrupt US aircraft operations on Guadalcanal in late 1942 also came to nothing.

However, by that time interest in using balloons to perform offensive actions against the US homeland was on the increase. The Japanese conducted a small number of attacks on the American mainland through World War II. In February 1942, Japanese Submarine I-17 shelled an oil field up the beach from Santa Barbara and damaged a pump house. That following June, Submarine I-25 shelled a coastal fort in Oregon, damaging a baseball backstop, and in September, that submarine's crew assembled and launched a small float plane that dropped incendiary bombs, starting a few small forest fires.

The same month, September 1942, the Imperial Japanese Navy (IJN) began work on what evolved over the next two years into a series of plans, produced under the direction of IJN Lieutenant Commander Kiyoshi Tanaka, to build bombing balloons that would be delivered by submarine. The workers tracked high-altitude winds using balloons fitted with radio beacons; the effort went as far as production of balloons and installation of hydrogen-generating equipment on submarines. The exercise came to nothing, since the pressures of war led to the cancellation of the program in the summer of 1944.

In the meantime, the IJA was working on their own bombing balloons. There was little or no cooperation with the IJN on the program: the two services had a case of interservice rivalry that defies belief and they fought, as the Japanese say, "like dogs and monkeys". The concept for the IJA balloon offensive was the brainchild of the Japanese Ninth Army Technical Research Laboratory, under Major General Sueyoshi Kusaba, with work performed by Technical Major Teiji Takada and his colleagues. The balloons were intended to make use of a great strong current of winter air that Japanese autonomous balloon flights by both the IJN and the IJA had discovered flowing at high altitude and speed over their country.

The "jet stream", as it would become known, blew at altitudes above 9.15 kilometers (30,000 feet) and could carry a large balloon across the Pacific, a distance of more than 8,000 kilometers (5,000 miles), in three days. Such balloons could carry bombs to the United States and drop them there to kill people, destroy buildings, and start forest fires. The Japanese named the weapon "fusen bakudan", which literally means "balloon bombs", but which has been translated as "fire balloons". The program was formally referred to as "FU-GO" -- this being translated in a number of ways.

* Building a balloon that could survive a three-day trip across the Pacific and then automatically drop its warload was technically challenging. Since a hydrogen balloon expands in the sunlight and rises, then contracts at night and falls, the Japanese engineers had to develop a battery-operated automatic control system to maintain altitude:

The balloon had to carry about 450 kilograms (1,000 pounds) of gear, which meant a hydrogen balloon with a diameter of about 10 meters (33 feet) and a volume of 540 cubic meters (19,000 cubic feet). At first, the balloons were made of conventional rubberized silk, but a cheaper approach was invented that resulted in an envelope that leaked even less. An order went out for ten thousand balloons made of "washi", a paper derived from mulberry bushes that was impermeable and very tough. It was only available in squares about the size of a road map, so it was glued together in laminations using paste derived from a tuber with the Japanese name of "devil's-tongue". The gasbag used three-ply paper on the bottom, four-ply on top.

fusen bakudan gondola model

Hungry workers stole the paste and ate it. Many workers were teen-aged girls, who were regarded as particularly dexterous. They were told to wear gloves, to keep their fingernails short, and not to use hairpins. They assembled the paper in many parts of Japan. Large indoor spaces, such as sumo halls, soundstages, and theaters were required for the envelope assembly. The workers had no idea of the purpose of their work. When rumors suggested the truth to them, that they were making balloons that would fly all the way to America and start fires, they laughed. Somehow secrecy was preserved.

* Initial tests took place in September 1944 and proved satisfactory. Boeing B-29 Superfortress bombers had been conducting raids on the Japanese home islands from mid-June; the attacks were ineffectual at first, but still angered the Japanese and fueled the desire to hit back. The first balloon was released in early November 1944. Major Takada watched as the balloon flew upward and over the sea: "The figure of the balloon was visible only for several minutes following its release until it faded away as a spot in the blue sky like a daytime star."

By early 1945, Americans were becoming aware that something strange was going on. Balloons had been sighted, explosions heard, from California to Alaska. An object that witnesses described as like a parachute descended over Thermopolis, Wyoming, followed by the explosion of a fragmentation bomb; shrapnel was found around the crater. A P-38 Lightning fighter shot a balloon down near Santa Rosa, California; another was seen over Santa Monica; and bits of washi paper were found in the streets of Los Angeles. Two paper balloons were recovered in a single day in Modoc National Forest, east of Mount Shasta. Near Medford, Oregon, a balloon bomb exploded in a blast of flame. The Navy found balloons in the ocean. Balloon envelopes and apparatus were found in Montana, Arizona, Saskatchewan, in the Northwest Territories, and in the Yukon. Eventually, an Army fighter somehow managed to herd one of the balloons around in the air and force it to ground intact, where it was examined and photographed

NEWSWEEK magazine ran an article titled "Balloon Mystery" in their 1 January 1945 issue, and a similar story appeared in a newspaper the next day. The Office of Censorship then sent a message to newspapers and radio stations to ask them to make no mention of balloons and balloon-bomb incidents, lest the enemy get the idea that they had a good thing going.

* The fact that the balloons had been launched beginning in the fall of 1944 made them little menace. The incendiary bombs could have caused forest fires, but by that time of year the forests of the western USA and Canada were generally too damp to catch fire easily. However, the authorities were still worried about the balloons. There was the chance that one might get lucky, dropping its warload on an important target. Much worse, the Americans had some knowledge that the Japanese had been working on biological weapons, and a balloon carrying biowarfare agents could be a real threat. In fact, there are reports that the Japanese did consider bioagent payloads for the balloons, but did not proceed with them.

Work began on setting up an air-defense system to spot and shoot down the balloons. Nobody believed the balloons could be coming directly from Japan. It was thought that the balloons must be coming from North American beaches, launched by landing parties from submarines. Wilder theories speculated that they could have been launched from German prisoner-of-war camps in the US, or even from Japanese-American internment centers.

Some of the sandbags dropped by the fusen bakudan were taken to the US Geological Survey for investigation. Geological Survey people had wanted to get involved in the war effort, either for the patriotism or prestige or both, and in mid-1942, they and provided a geological intelligence report for a randomly chosen country, Sierra Leone, describing the terrain, locations of water supplies and road-building materials, and other obviously useful facts. The military bought the idea and so a "Military Geological Unit" was formed.

Working with US Army Intelligence, the researchers of the Military Geological Unit began microscopic and chemical examination of the sand from the sandbags to determine types and distribution of diatoms and other microscopic sea creatures, and its mineral composition. The sand could not be coming from American beaches, nor from the mid-Pacific. It had to be coming from Japan, and in fact the researchers would ultimately identify the precise beaches that the sand had come from.

* In the meantime, the balloons continued to arrive in Oregon, Kansas, Iowa, Manitoba, Alberta, Northwest Territories, Washington State, Idaho, South Dakota, Nevada, Colorado, Texas, northern Mexico, Michigan, and even the outskirts of Detroit. Fighters scrambled to intercept the balloons, but they had little success; the balloons flew very high and surprisingly fast, and the fighters destroyed fewer that 20.

Japanese propaganda broadcasts announced great fires and the American public in panic, declaring casualties as high as 10,000, but only six people were killed, the only casualties inflicted by the enemy on the American mainland in World War II. On 5 May 1945, a minister and his wife took some children on a fishing trip in southern Oregon, east of the Cascades, when they discovered a balloon bomb that had fallen to earth some weeks before. It exploded while they were gathered around it, killing the woman and five children. The press blackout was lifted after the deaths to ensure that the public was warned, though the public notifications were low-key in order to avoid hysteria.

The irony was that the balloon offensive was over by that time. General Kusaba's men had launched more than 9,000 balloons, of which about 300 were reported in the US. The Japanese estimated that about 10% would complete the trip, and in fact it is thought that about a thousand did so. Two landed back in Japan, but caused no damage.

The expense of the program was great, and in the meantime the increasingly fearsome B-29s had destroyed two of the three hydrogen plants needed by the project. With no evidence of any effect, General Kusaba was ordered to cease operations in April 1945, after about six months of operations. The public warnings were for a threat that no longer existed, though it was still prudent to warn the citizenry not to tinker with balloons that had come to rest in a forest or cornfield. Components of the balloon bombs were found for years, the last time in 1978, and are no doubt are still lingering, overgrown in the brush and trees in remote, inaccessible wild areas of the US and Canada.

Although the fusen bakudan were much more sophisticated than the British OUTWARD balloons, the fusen bakudan program proved a failure, amounting to little more in hindsight than a malevolent curiosity. In terms of economics, it did cause the Americans to expend more resources than the Japanese had invested in the balloon program -- but the US had resources to spare, and it's hard to think that the fusen bakudan program extended the survival of Imperial Japan by a single minute. Indeed, although the fusen bakudan demonstrated Japanese ingenuity, they also demonstrated the staggering imbalance of material capability between Japan and the USA: the futile balloon bombings were laughable, in contrast to the horrific destruction of Japan's cities by American bombers.

The fusen bakudan did have a minor success. On 10 March 1945, one of the last of the fusen bakudan had descended in the vicinity of a production site of the secret Manhattan Project at Hanford, in Washington state. The balloon landed on a power line that fed electricity to the building containing the reactor producing plutonium for the Nagasaki bomb, and shut the reactor down. Backup generators came online to restore power.