Observation balloon

An observation balloon is a type of balloon that is employed as an aerial platform for gathering intelligence and spotting artillery. The use of observation balloons began during the French Revolutionary Wars, reaching their zenith during World War I, and they continue in limited use today. Synonyms include espionage balloon, reconnaissance balloon, spy balloon, and surveillance balloon. Historically, observation balloons were filled with hydrogen. The balloons were fabric envelopes filled with hydrogen gas, the flammable nature of which led to the destruction of hundreds of balloons. Observers manning these observation balloons frequently had to use a parachute to evacuate their balloon when it came under attack. Observation balloons after World War I were often filled with non-flammable helium to avoid the potentially explosive consequences of hydrogen. Typically, balloons were tethered to a steel cable attached to a winch that reeled the gas bag to its desired height (usually 1,000-1,500 metres) and retrieved it at the end of an observation session. History of military ballooning and Balloon buster The first military use of observation balloons was by the French Aerostatic Corps during the French Revolutionary Wars, the very first time during the Battle of Fleurus (1794). The oldest preserved observation balloon, L'Intrépide, is on display in a Vienna museum. They were also used by both sides during the American Civil War (1861–65) and continued in use during the Franco-Prussian War (1870–71). Balloons were first deployed by the British Army's Royal Engineers during the expeditions to Bechuanaland in 1884 and Suakin in 1885. They were also deployed during the Second Boer War (1899–1902), where they were used in artillery observation at the Battle of Magersfontein and during the Siege of Ladysmith. In South America, a reconnaissance balloon was deployed by Brazil in July 1867 during the Paraguayan War. World War I was the high point for the military use of observation balloons, which were extensively deployed by both sides.