Have you ever seen a white balloon flying in the sky? Did you think it looked strange? If so, you might just be looking at a spy balloon.

On Jan. 31, the recent Chinese spy balloon was first spotted hovering above Northern Idaho before drifting over Montana. Idaho Senator Jim Risch issued a sharp rebuke of the activity, telling reporters that the balloon represented an invasion but didn’t fly over sensitive locations.

And while this might seem like an outdated method of espionage in today’s high-tech world, it’s still an effective way for countries to spy.

Spy Balloon Origins

Some of the first recorded usage of spy balloons occurred during the French Revolution. The French military used balloons for observation in their battle of Fleurus against Britain, Germany and the Netherlands. The information they collected from these balloons may have just helped the French emerge victorious. The balloons saw later use in the battle of Charleroi. The corps d’aerostiers became a part of the French army, disbanding four years later.

On April 12, 1861 at the start of the Civil War, Thaddeus Lowe earned the trust of President Lincoln and started creating spy balloons for the U.S. Lowe was later named Chief Aeronaut in the newly created balloons corp and invented seven of the balloons used by Union forces.

Lowe’s balloons could reach up to a thousand feet with a capacity of 32,000 cubic feet of lifting gas. While the largest balloons, the Intrepid and Union could fit five people or four and a telegrapher, the smallest, the Eagle and Excelsior, had room for only one person. On the ground, these balloons were always tied down by at least 4 to five ropes in case of the wind.

However, the balloons used by Lowe were nothing secretive. They displayed bright colors and designs to intimidate the confederates. They were positioned one thousand feet up in the air, high enough to watch and not get hit.

Even though most balloons were used by the Union, the Confederates had a couple of their own. They used a balloon on a tugboat to monitor the union’s movements during the seven-day campaign on the James River. They were soon forced to flee and leave their boat and balloon behind. The balloons were sometimes efficient and other times not so much. Commanders eventually decided that the limitations outweighed the advantages as the balloon corps disbanded in 1863.

Spy Balloons in the 20th Century

Balloons were used again for military purposes during World War I, only this time they were armed with shotguns and bombs. During World War II, they were used less frequently because of the evolution of planes, which were able to shoot down balloons more easily, oftentimes from German altitude bombers. Balloons were also used to find trench lines and enemy bases while overwater to find ships and submarines.

“The U.S. Army even used balloons in recent wars in Iraq and Afghanistan called aerostats,” said Thomas Paone, an aerospace engineer at the Smithsonian’s Aerospace Museum. “These balloons would be placed at a military base and would float aloft with cameras and other sensors to allow people on the ground to watch for attacks or other things that were happening around the base.”

On February 4, 2023, the U.S. military shot down the Chinese spy balloon was shot down over the coast of South Carolina, receiving the same fate as several others have over the past six years.

And while it might seem like a mission that was doomed to fail, it begs the question: Why not use planes or satellites?

Despite their primitive nature, balloons are still cheaper to operate and require less maintenance since they don’t need to refuel as often. Planes and satellites take much longer to gather information and cost more money to use and maintain.