On Feb. 4, the US military shot down a giant white balloon in US airspace, suspecting it to be a Chinese surveillance device. Since then, US planes have shot down three more unidentified flying objects over the US and Canada.
These aerial encounters take place amid a climate of heightened geopolitical tension between Washington and Beijing.
Tomorrow, the Weekend Brief will look at the history of balloon espionage programs and the key features that differentiate these surveillance devices from typical satellites launched into space.
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