Operation Outward

Operation Outward was a British campaign of the Second World War that attacked Germany and German-occupied Europe with free-flying balloons. It made use of cheap, simple balloons filled with hydrogen and carrying either a trailing steel wire to damage high voltage power lines by producing a short circuit, or incendiary devices to start fires in fields, forests and heathland. A total of 99,142 Outward balloons were launched; about half carried incendiaries and half carried trailing wires.^[a]

Compared to Japan's better-known fire balloons, Outward balloons were crude. They had to travel a much shorter distance so they flew at a lower altitude – 16,000 ft (4,900 m), compared with 38,000 ft (12,000 m) – and had only a simple mechanism to regulate altitude by means of dropping ballast or venting lifting gas. This meant the balloons were simple to mass-produce and only cost 35 shillings each (approximately equivalent to £121 in 2024^[3]). The free flying balloon attacks were highly successful. Although difficult to assess exactly, their economic impact on Germany was far in excess of the cost to the British government.^[2][4][5]

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