Surveillance balloons are having a moment – even beyond the recent Chinese spy balloon fiasco.
The US and UK militaries are increasingly funding projects to build high-tech surveillance balloons that operate at nearly 20 kilometres up in the air. And though Chinese officials have said that the balloon at the centre of the recent incident was a weather-monitoring balloon and not a spy balloon, China has also been putting a greater focus on surveillance balloons.
“You can fit a lot more surveillance capacity on a balloon now than you could have 10 or 15 years ago,” says at the Carnegie Council for Ethics in International Affairs, a think tank in New York.
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The US Pentagon is reportedly planning to spend more than – a sevenfold increase from spending in previous years. The aim is that the balloons will be able to communicate with satellites to track hypersonic missiles and other aerial threats along with activity on the ground.
The UK Ministry of Defence is also interested in balloons – its aims to develop uncrewed air systems for surveillance missions anywhere in the world. In October 2022, the Sierra Nevada Corporation and the balloon company World View held a Project Aether demonstration by launching a balloon that travelled from Arizona north-east across several additional states.
The New York Times has that Chinese military scientists are working on making balloons more “more durable, more steerable and harder to detect and track”.
In recent years, balloon surveillance capabilities have been buoyed by miniaturised computers and sensors, along with efficient solar panels to power those electronics. Weather prediction models and artificial intelligence also now help balloons to use stratospheric winds to get where they want to go or continuously hover above an area of interest, says , vice president of stratospheric solutions at Aerostar in South Dakota.
Aerostar has been developing high-altitude balloons for customers such as the US Navy and NASA since the 1950s. But it was the company’s work for Alphabet’s now-defunct Project Loon between 2012 and 2021 – which tested stratospheric balloons as internet connectivity hubs – that unlocked the navigational and steering capabilities coveted for both military and civilian use, says Van Der Werff. Aerostar’s latest balloons can operate for up to 150 days at a time.
Balloons can capture images with the same resolution as more expensive spy satellites, and they can monitor the same area for much longer periods than orbiting satellites passing overhead, says at the RAND Corporation, a think tank based in California. Balloons are also cheaper and more expendable compared with crewed aircraft or high-end drones. And because they fly so high and don’t show up well on radar, that makes it difficult for expensive surface-to-air missiles and fighter jets to counter them.
But as the Chinese-launched balloon shows, balloons are “perfectly capable of causing an international incident” by flying through a country’s airspace, says Tannehill. That incident also shows the risk of trespassing balloons being captured and exploited for information.
There is no guarantee that increased military funding will mean success. The US Army spent more than $2 billion on its JLENS project to develop tethered radar-toting blimps for detecting cruise missiles and drones, before congressional support deflated when a blimp broke free and destroyed power lines as it drifted across Maryland and Pennsylvania in 2015. “A lot of money has been spent on surveillance technologies that never panned out,” says Holland Michel.
