During the course of World War II, all sides had their own secret projects intended to give them a strategic edge. The United States was working on a massive bomb that could put an immediate end to the conflict. In Japan, researchers were hard at work on Fu-Go, a unique weapon that, on the surface, sounds completely impractical. The Fu-Go, or fire balloon, was exactly what it sounds like: a balloon that was intended to deliver a deadly payload.

The Fu-Go was in production for only a few months before being retired, but their simple and inexpensive construction meant that a lot of them could be manufactured over a short period of time. From November 3, 1944 to April 1945, some 9,300 fire balloons were built by Japan. Of those, roughly 300 were sighted or found in the United States.

Fu-Go: From Concept to Reality

The same nation that had the ingenuity to pull off what should have been an impossible attack on an active American naval base also came up with the design for the Fu-Go. As the war wore, with no end in sight and the United States enjoying victory after victory in the Pacific, Japan sought a means of damaging American morale. Since it couldn’t do so in the islands they were struggling to hold onto, the Imperial Japanese Ninth Army’s Number Nine Research Lab came up with an idea for a weapon that could effectively reach the United States and create panic.

The concept was simple, and to maximize its effectiveness the Japanese produced two types: the Type B Balloon and a the much deadlier bomb-carrying balloon. The Type B was made of a rubberized silk and was first used by meteorologists. The Type B eventually gave way to the bomb-carrying balloon after it was determined that they were durable enough to survive a trip to the North American mainland.

Implementing the Fire Balloon

Fu-Go releasing ballast

Fu-Go releasing ballast

Conceived by Major General Sueyoshi Kusaba and Technical Major Teiji Takada, the balloons were designed to catch the jet stream, a current of strong winter winds that meteorologists had observed at high altitudes over the Pacific. The hope was that this air stream would carry the balloons to the United States before weakening over land, allowing the balloons to drop, causing scattered explosions that would cause death and property damage.

The team that worked on the balloons faced many challenges, starting with the fact that the hydrogen-fueled balloons would expand and rise when warmed, then fall in cooler temperatures. To counter this problem, engineers utilized a control system that worked with an altimeter to counter the natural effects of warming and cooling. When a balloon dipped below 30,000’, it would automatically drop sandbags that were used to weigh it down, allowing it to remain at an optimum altitude for the remainder of its flight. To counter reaching higher altitudes, the balloon would vent hydrogen when it reached 38,000’ to prevent it from soaring too high.

For the assault against the United States, the Fu-Go balloons were equipped with either a Type 92 15kg bomb composed of picric acid or TNT, a Type 97 12kg thermite incendiary bomb, or a 5kg thermite incendiary bomb. Along with bombs, Japan had hoped to release biological weapons over the United States, including anthrax and cowpox. Due to the short lifespan of the fire balloons, this strategy was never brought into operation.

Going on the Offensive

With the fire balloons designed and ready for implementation, Japan organized an initial three battalions to oversee their launch. Based along the eastern coast of the Japanese island of Honshu, the battalions oversaw different stages of production and carefully monitored weather conditions for the perfect time to launch.

In September of 1944, Japan started initial tests of the fire balloon campaign and, by November 3, after an American B-29 raid on the Japanese home islands, the first balloons were launched. Within a day, the US Navy happened upon a balloon floating aimlessly off San Pedro, CA, causing an increased level of alert across the United States. As effective as Japan had projected the campaign would be, very little damage was being done.

Japanese fire balloon shot down near the Aleutians, April 1945

Japanese fire balloon shot down near the Aleutians, April 1945

Still, US officials thought it best to head off the lighter-than-air bomb-carriers before they reached the North American mainland, and so they launched fighters to try and shoot down as many as possible. Due to their altitude and speed, the balloons were surprisingly elusive and only approximately 20 were actually destroyed by the American warplanes.

Fearing the spread of wildfires in the Pacific forests, the Fourth Air Force, Western Defense Command and Ninth Service Command came up with the Firefly Project. Consisting of 2,700 troops, among which were 200 paratroopers, Firefly set up posts along the Pacific coast to combat fires that started from the bombs. The men of Project Firefly sustained 23 injuries due to fires, one of which was fatal.

Though the balloons terrorized the United States for a short period, the campaign was largely ineffective. Not willing to admit failure, though, Japan released propaganda promising its people that the United States was in a panic and casualties reached into the thousands. The reality was there was only one reported lethal interaction with a balloon, an encounter that left a pregnant woman and five children in her care dead.

The Oregon Incident

Monument to Elsie Mitchell and five children killed by a Japanese fire balloon

Monument to Elsie Mitchell and five children killed by a Japanese fire balloon

On May 5, 1945, Elsie Mitchell and children from her church came across a balloon in the woods of Gearhart Mountain in southern Oregon. While looking for a spot to enjoy a picnic, Elsie and the children found a balloon lying on the ground. It exploded almost immediately, killing four boys. Elsie survived the initial blast but died in her husband’s arms, and the fifth child, a girl, died later.






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