One of the more surreal sights of the recent Afghan war was tethered balloons (also known as “aerostats”) looming over the bases of international forces. These “persistent threat detection systems” carried a suite of 360-degree cameras providing a constant view—out to 100 miles—of surrounding areas to the US “force-protection” teams within the heavily guarded installations.
China's spy balloon: Inflatable eyes in the sky have been used in war for centuries
