Weather Balloon Gone Rogue or Spy Vessel at Work? We Ask the Experts.

A suspected spy balloon—or stray weather device—risks blowing U.S.-China relations off course.

The U.S. called it a spy balloon sniffing on sensitive military sites and shot it down. China said it was a weather device blown off course and accused Washington of overreacting.

Whichever it was, the giant, mysterious orb that hovered over Montana for days has set off a diplomatic row. As the U.S. military works to recover the remnants of the Chinese vessel off the coast of South Carolina after it was downed Saturday, the wreckage could hold the answer to a question at the center of the controversy: What was the balloon for?


“It’s absolutely not a weather balloon,” Gregory Falco, an assistant professor of Civil and Systems Engineering at John Hopkins University, told VICE World News, echoing an assessment by meteorologists and atmospheric scientists. “It’s kind of funny that’s the claim because weather balloons are not designed to look like this.”

Falco pointed to the balloon’s unusually large payload, which holds sensors and what are likely radar systems that are pointed downward rather than upward, according to images of the vessel. 

The balloon is estimated to be the size of three buses, which stood out to Iain Boyd, an aerospace engineer at the University of Colorado Boulder and the director of the university’s Center for National Security Initiatives. “It is much larger than weather balloons. So that seems a little bit odd,” Boyd said. 

The Pentagon first announced it was actively tracking what it called a Chinese surveillance balloon on Thursday. The U.S. F-22 fighter jet shot it down on Saturday, after waiting until it was over open water to prevent debris from crashing to earth. Its presence, which caused uproar in Washington, prompted U.S. Secretary of State Antony Blinken to cancel his weekend visit to China, dashing hopes of a reset in bilateral ties, which have been in a downward spiral for years over issues such as trade and Taiwan. Whether the balloon's entry was intentional or not, observers said the incident is set to harm Beijing. 


“The Biden administration concluded that had the visit gone forward it would have been dominated by discussion of this incident and made it difficult, if not impossible, to achieve the objectives of putting a floor under the relationship,” Bonnie Glaser, director of the Asia Program at think tank the German Marshall Fund of the United States, told VICE World News. 

If the floating orb is indeed a spying device as the U.S. asserts, it also begs the question of what China is getting out of the operation, given other more advanced tools available. Compared to spy satellites in low earth orbits, a balloon is much closer to ground and can capture clearer images. But it has obvious limitations, including its slow speed, high visibility, and difficulty to control.

“There certainly are military purposes for balloons, but not for this apparent application of flying thousands of miles over someone else’s country gathering information,” Boyd said. “If that was deliberate, they were really asking for a lot of trouble.”

Another theory, Boyd added, is that it’s some kind of experimental surveillance balloon that the Chinese government lost control of and drifted further than anticipated. 

The Chinese foreign ministry said in a statement on Friday that it was a civilian airship for scientific purposes. Affected by the wind and with limited self-steering capability, it deviated from its scheduled route and entered U.S. airspace due to “force majeure,” it said. China also removed its national weather chief from his position on Friday without offering a reason, fueling speculation that the device’s entry into the U.S. airspace was an unfortunate blunder. 


Speaking at a press briefing on Monday, Mao Ning, a Chinese foreign ministry spokesperson, confirmed that a second balloon, which has been detected over Latin America, belongs to China and insisted it is also for civilian purposes. 

Besides capturing images, Falco of John Hopkins suggested the balloon could be on a reconnaissance mission, grabbing side lobes—far field radiation patterns of an antenna—to eavesdrop on radio frequency communications. 

“This is just one of the continuous background surveillance and espionage activities that are happening across nation states,” Falco said, adding balloons are more commonly used by countries than expected, even if they aren’t always in the public eye. The Pentagon, for instance, has spent about $3.8 million on balloon projects in 2021 and 2022. 

“I think this was a situation where it was a little bit more blatant than they intended it to be,” Falco said. 

Boyd said the answer to these questions would be clear after the U.S. military recovers and analyzes the debris, as the instruments needed for each purpose are very different. But Falco noted that China is aware of the risk of the device being recovered and may have made sure everything was wiped or destroyed. 

Either way, both experts agree the balloon itself is not as big of a threat to U.S. national security as what the vehicle symbolizes. A senior U.S. defense official also told reporters on Thursday that the balloon has “limited additive value from an intelligence collection perspective.”

“Part of me also wonders whether China really decided to do this provocative act as it underestimated the strength of the response from the US and the broad international interest in this story,” Boyd said.

Follow Rachel Cheung on Twitter and Instagram.