In an era when orbiting satellites were so advanced that they could make out objects half the size of cars from space, spy balloons might seem a bit like relics.
They were an important tool for reconnaissance during the Cold War, and were even used in a more basic form for intelligence gathering during the Napoleonic Wars more than 200 years ago.
But security experts say balloons are just the “tip of a revolution” in the development and use of new high-altitude surveillance aircraft, with Britain investing millions of dollars in a project to develop spy balloons last year.
Saturday, USA Suspected Chinese spy balloon shot down has been flying over its airspace.
A senior defense official previously said the US was “very confident” it was a Chinese high-altitude balloon that was flying over sensitive sites to gather information, and China did not immediately deny that the balloon belonged to them.
The Pentagon acknowledged reports that a second balloon was spotted flying over Latin America, saying: “We now assess it to be another Chinese surveillance balloon.”
The sightings prompted U.S. Secretary of State Anthony Blinken to postpone a high-profile visit to China scheduled to begin Sunday, while the Pentagon accused Beijing of spying on sensitive military sites.
Beijing acknowledged that the original balloons came from China, but insisted they were “civilian airships” strayed into U.S. airspace for meteorological and other scientific research.
What is a spy balloon?
These devices are lightweight balloons filled with gas, usually helium, and attached to spy equipment such as remote cameras.
They can be launched from the ground and then rise into the air, reaching altitudes between 60,000 feet (18,000 meters) and 150,000 feet (45,000 meters), above the flight path of commercial aircraft, known as “near space.”
Once in the air, they travel using a mixture of airflow and pressurized air pockets, which can act as a form of turning.
Why are they still useful in the age of satellites?
According to defense and security analyst Professor Michael Clarke, the biggest advantage spy balloons have over satellites is that they can study an area over a longer period of time.
“The advantage is that they can stay in one place for a long time,” he told Sky News.
“Because of the way the Earth spins, unless there are satellites over the equator, you need three to five satellites running all the time to track the same spot.
“These balloons are also relatively cheap and easier to launch than satellites.”
Will balloons continue to be used as spies in the future?
According to Professor Clark, very important.
Despite the widespread use of satellite technology, countries including the UK have also focused on developing and using spy craft to operate in the upper atmosphere.
August, announced Ministry of Defense A £100m deal has been struck with US defense company Sierra Nevada to supply high-altitude unmanned balloons for surveillance and reconnaissance.
“(These balloons) are the cusp of a revolution in passive upper-atmospheric vehicles,” Professor Clarke said.
Other defense companies, such as BAE, are working on ultralight, solar-powered drones capable of operating in the upper atmosphere and staying in place for up to 20 months, he said.
Why is China using them now?
According to Professor Clarke, the use of these balloons, if they were indeed launched by China, is likely to be a message to the US following its decision to open a new military base in the region the Philippines.
“I think it’s a challenge,” he said.
“They (China) are signaling that if the U.S. is going to get close to them, then they will be more aggressive in their surveillance.
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“It’s also creating a political problem now in the US because not shooting it down would be seen as a sign of weakness.
“It’s going to cause some embarrassment, but the U.S. doesn’t need to respond.”
Balloon spotted over Billings, Montana, Wednesday – near one of three US nuclear missile silos at Malmstrom Air Force Base.
Military and defense leaders initially decided not to shoot down the balloon because of the safety risk from falling debris.
Prof Clark added: “I think the debris issue is an excuse. It’s one of the most depopulated areas in the US and they could have asked everyone to stay inside if they needed to.
“I don’t think they want it to be a bigger problem because China is provoking them to shoot it down and make it an international problem.”