Originally Posted by
ORAC
They coul£ have been flying balloons through NATO airspace for years and no one will even have been aware as the processing used to remove cloud clutter from radar (Doppler MTI/MTD), will also remove anything drifting with the wind.
It seems strange that the US routinely tracks small items of satellite debris in orbit, but apparently cannot track a balloon that is carrying a metallic payload and in some cases a large solar array with copper cables.