In an age of orbital satellites so advanced they can distinguish objects half the size of a car from space, a spy balloon might seem like a bit of a relic.
They were an important tool for reconnaissance during the Cold War and were even used in a more basic form for intelligence gathering in the Napoleonic Wars more than 200 years ago.
But security experts say the balloons are just the “tip of a revolution” in the development and use of new means of high-altitude surveillance, with the UK even investing millions in a project to develop spy balloons last year.
It comes as the US military on Friday said it was tracking a suspect Chinese spy balloon, described as the size of three buses, which has been flying over Northwest America in recent days.
A high-flying balloon flies over Billings in Montana
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Chinese spy balloon flying over US airspace, Pentagon says
The spy balloon over the United States is actually a “civilian airship,” says China
A senior defense official said the WE has “very high confidence” it is a Chinese high-altitude balloon and was flying over sensitive sites to gather information, while China did not immediately deny that the balloon belonged to them.
Beijing admitted the balloon came from China, but insisted it was a “civilian airship” that had gone missing in American airspace and was intended for meteorological and other scientific research.
US Secretary of State Antony Blinken has postponed a high-profile visit to China that was due to start on Sunday.
What are spy balloons?
The devices are lightweight balloons filled with gas, usually helium, and attached to spy equipment such as a long-range camera.
They can be launched from the ground and sent into the air where they can reach altitudes of between 60,000 feet (18,000 m) and 150,000 feet (45,000 m), above the flight paths of commercial aircraft in an area known as “near space”.
Once in the air, they travel using a mixture of air currents and pressurized pockets of air, which can act as a form of steering.
Why are they still useful in the age of satellites?
According to defense and security analyst Professor Michael Clarke, the biggest advantage of spy balloons over satellites is that they can study an area over a longer period of time.
Professor Michael Clarke
“The advantage is that they can stay in one place for a long time,” he told Sky News.
“Because of the way the Earth rotates, unless a satellite is above the Equator, it takes three to five moving satellites to track the same point.
“These balloons are also relatively cheap and much easier to launch than a satellite.”
Will balloons continue to be used for espionage in the future?
A lot, according to Professor Clarke.
Despite the extensive use of satellite technology, countries including the UK are also focusing on the development and use of spy aircraft to operate in the upper atmosphere.
In August it was announced the Ministry of Defence it had agreed a £100m deal with US defense company Sierra Nevada to supply high-altitude unmanned balloons to be used for surveillance and reconnaissance.
Professor Clarke said: ‘(These balloons) are the pinnacle of the revolution for passive aircraft in the upper atmosphere.’
He said other defense companies, such as BAE, are working on ultralight solar-powered drones that can operate in the upper atmosphere and stay in place for up to 20 months.
Why did China use them now?
According to Professor Clarke, the use of these balloons, if indeed they were launched from China, will probably have been a message to the United States following its decision to open new military bases in the Philippines.
“I think it’s a challenge,” he said.
“They (China) are signaling that if the US gets close to them, then they will be more aggressive with their surveillance.
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“It’s also a political problem in the US now, because not bringing it down will be seen as a sign of weakness.
“This causes some embarrassment, but the United States does not need to respond.”
The balloon was spotted over Billings, Montana, Wednesday – near one of three US nuclear missile silo fields at Malmstrom Air Force Base.
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Mao Ning, Chinese Foreign Ministry spokesman, says those involved should be “cold”
Defense and military leaders said they considered shooting the balloon from the sky but decided against it due to the safety risk from falling debris.
Professor Clarke added: ‘I think the debris issue is a bit of an excuse. It was over one of the least densely populated areas in the US and if they needed to they could have asked everyone to stay inside.
“I don’t think they wanted to make it a bigger problem, because China is daring them to take it down and make it an international problem.”
