From balloons on the battlefields of the American Civil War to unmanned and jet-powered drones, the best way to spy on the enemy has always been from above. Here’s how aerial surveillance technology has evolved over the past 200 years.
In the early 1790s, the French first experimented with using hydrogen-filled balloons to detect enemy data on the battlefield. They did not actually fly over enemy lines, but were tethered to the ground by cables. The balloon baskets carried two soldiers: one with a telescope and the other who signaled the observations to the ground using flags. French balloonists formed the world’s first air force in 1794 called the “Compagnie d’Aéronautiers”.
“Before that moment, the only way to understand the enemy’s position was to send out a group of cavalry to scout. Meanwhile, from above, riding in a balloon, you could see up to 80 km away on a clear day. So it offered an extraordinary advantage for observing the enemy,” says Andrew Hammond, historian and curator at the International Spy Museum in Washington. After the outbreak of the Civil War in the US, American inventor Thaddeus Lowe organized a balloon demonstration at the National Mall, convincing President Abraham Lincoln to use observation balloons in the Union Army. The largest reconnaissance balloon, the Intrepid, could carry 5 people, including a telegrapher who would transmit information about the positions of the Confederate Army.
In the 1880s, British meteorologist Douglas Archibald experimented with large balloons to study wind speed. He mounted a camera on the balloon. Archibald’s aerial photographs were some of the earliest ever published, and they caught the attention of American military officer William Eddy.
While fighting in the Spanish-American War of 1898, he built his own version of Archibald’s camera and used it to take 90-degree photographs of enemy positions. Although photography had existed during the Civil War, Eddie took the first military aerial surveillance photos in history. Pigeons played a vital role in World War I communications. They carried SOS bulletins from sailors at sea, relayed orders to tank officers, and carried coded messages from secret spies. Pigeons were also used to take aerial photographs.
In 1907, German pharmacist Julius Neubroner patented a camera mounted on a pigeon, and used his invention to create impressive postcards. During World War I, the German military experimented with photographing the birds, which were more stealthy than spy planes.
“They would attach a camera to pigeons and send them over enemy trenches in France,” says Hammond. But the photos were blurry and very difficult to interpret. “The history of intelligence and espionage is filled with many more failed attempts than those that worked. The CIA also tested a lightweight camera mounted on pigeons to take close-up photos of targets, but the birds were very difficult to control,” the historian points out. Airplanes have been used in warfare since World War I. But before they were equipped with machine guns and bombs, they were used for reconnaissance. The two-seater aircraft carried a pilot and an observer, who sketched the structure of enemy troops with the help of binoculars. Then came cameras.
The Eastman Kodak Company in the US designed some of the first aerial cameras to be mounted on the wings of the British-made de Havilland DH-4 aircraft. Other World War I cameras could take pictures through a hole in the cockpit floor.
During World War II, surveillance planes began to carry a portable darkroom on board for developing and analyzing aerial photos in near real time. During the Cold War, the KGB made it nearly impossible to gather intelligence on the ground in the Soviet Union, so American spy agencies turned to space. “Necessity is the mother of invention. That’s why the famous U2 was designed, which could fly up to 70,000 feet, or more than twice the altitude of today’s commercial jets,” says Hammond. The U2 was equipped with a Hycon 73B camera, capable of capturing minute details up to 30 inches wide from dizzying heights. In 1962, a U2 plane captured images of Soviet nuclear weapons in Cuba, sparking the Cuban Missile Crisis. For the US and the Soviet Union, the space race was about more than just who could land on the moon first. Secret services were actually trying to put the first spy satellites into orbit.
“Today, satellites are for commercial purposes. But back then, they were primarily for defense and military purposes,” says Hammond. In the late 1950s, the U.S. Air Force launched the “Discoverer” program to collect scientific data via satellites. At least, that was the official version.
In reality, it was a secret espionage program called “Project Corona.” American spy satellites produced their first aerial images of the Soviet Union in 1960. The most powerful weapon in this regard was the “HEXAGON KH-9,” an American spy satellite that could capture images of objects smaller than 70 cm from 160 km above the Earth’s surface.
Before digital images could be transmitted from space, the KH-9 parachuted images into the atmosphere over the Hawaiian Islands, where they would be picked up by U.S. Air Force aircraft. One of the most sensational devices now housed in the CIA Museum is the Insectopter, a covert surveillance device camouflaged as a realistic-looking dragonfly. The CIA built this surveillance device in the 1970s, after abandoning an earlier attempt to build a surveillance device in the shape of a wasp. The Insectopter’s translucent wings were powered by a small gasoline engine. It flew so fast that it could cover the length of two football fields in just 60 seconds.
An operator controlled its flight using laser beams, which transmitted sounds picked up by the artificial insect’s tiny microphone. Unfortunately, the Insectopter never became operational because it easily veered off course if winds exceeded 5 mph (8 km/h).
UAVs, or “unmanned aerial vehicles,” appeared as early as World War I with the “Aerial Target,” a British remotely piloted aircraft. The Royal Air Force used UAVs to target British gunners in 1917. During World War II, the RAF upgraded its UAV fleet to the “Queen Bee,” a reusable training target for anti-aircraft gunners. The first jet-powered drones were used in the Vietnam War as part of a secret American reconnaissance program. The AQM-34 Ryan Firebee, which flew more than 34.000 surveillance missions during the war, was equipped with radar-evading devices. In addition to tracking Viet Cong positions and identifying targets, the Firebee was also used to deliver propaganda leaflets behind enemy lines.