While China insisted that the white orb that floated over the continental United States last week was an unrecoverable weather balloon, officials in Washington, DC, said the balloon was a spy device set up by Beijing to monitor sensitive areas.
The high-profile plot has drawn attention to so-called “spy balloons” and the seemingly old-fashioned role of technology in modern espionage.
On Saturday, a U.S. fighter jet shot down a Chinese balloon off the coast of South Carolina, and officials said the recovery attempt would reveal more details about the Chinese device’s capabilities.
Beijing condemned the move as “a clear overreaction and a serious violation of international practice”, exacerbating a political whirlwind that has already seen Secretary of State Antony Blinken postpone a planned visit to China.
Why do governments use surveillance balloons?
In the age of satellites, surveillance balloons — which are usually advanced balloons equipped with high-tech downward imaging equipment — offer up-close monitoring, Iain Boyd, a professor of Aerospace Engineering Sciences at the University of Colorado Boulder, told The. Talk News Page. Balloons are sometimes subject to the weather, but may be equipped with a “guidance device” that controls their path.
While satellites remain “the preferred method of overhead spying,” lower-flying balloons that hover at about the same altitude as commercial airlines can usually produce clearer images than the lowest-orbiting satellites, Boyd explained. This is mainly due to the speed of such satellites, which complete one Earth orbit in 90 minutes.
Another type of satellite can spin in sync with Earth, allowing it to capture continuous images of a single location, according to Boyd, although such satellites orbit further from the planet and therefore tend to produce foggier images.
Surveillance balloons may also be capable of “picking up electronic signals” and intercepting communications, according to David DeRoches, a professor at the Middle East South Asia Center for Strategic Studies at the National Defense University in Washington, DC.
He told Al Jazeera that the Chinese balloon shot down by the US could also have been used to “gather information about what kind of signals [the US is] used for tracking, so it could possibly identify and classify radar hits… which could be interesting if the Chinese really want to launch an attack.”
What did the US say about the balloon?
U.S. officials said the Chinese balloon was about the size of three school buses and entered the U.S. air defense zone north of Alaska’s Aleutian Islands on Jan. 28, moving over Alaska and into Canadian airspace over the Northwest Territories on Jan. 30, before which returned to US territory over northern Idaho the next day.
Officials did not offer many details about the technology on the balloon, although they were adamant that it was a “surveillance balloon.” Officials said the balloon was estimated to have engines and propellers, allowing it to maneuver.
“We are convinced that he was trying to monitor sensitive military locations,” a senior defense official told reporters on Saturday.

Officials also argued that the balloon posed no threat to civilian air traffic or to people or property on the ground, and that US authorities had preliminarily determined that it did not significantly increase Beijing’s “intelligence capabilities” beyond the government’s pre-existing satellite surveillance assets.
The balloon was brought down off the coast of South Carolina by a single AIM-9X Sidewinder air-to-air missile fired by an F-22 fighter jet, leaving a debris field that stretched at least 11.2 km (7 miles), according to the Pentagon. The US Navy led the effort to recover the wreckage to further analyze the device.
History of surveillance balloons
US officials also revealed that foreign balloons entering US airspace have been relatively common in recent years, with a senior defense official telling reporters on Saturday that Chinese “government surveillance balloons have briefly passed over the continental United States at least three times”. during the administration of former President Donald Trump, who took office in January 2017 and left in January 2021.
US officials said the second balloon spotted over South America last week was also a Chinese surveillance balloon.
Primitive forms of observation balloons began to be used in the 1800s.
France used manned surveillance balloons in the Franco-Austrian War of 1859. Manned and tethered balloons were used again soon after during the American Civil War, which lasted from 1861 to 1865.

Observation balloons became common in World War I and World War II. During the last war, the Japanese military used balloons to drop incendiary bombs on US territory. No military targets were damaged, but several civilians were killed when one of the balloons crashed in a forest in Oregon.
Immediately after World War II, the U.S. military began investigating the use of high-altitude spy balloons, leading to a series of large-scale missions called Project Genetrix.
The program says photographic balloons were flown over Soviet-bloc territory in the 1950s, according to government documents.