Small balloons (similar to what have been shot down recently) have few regulations regarding their use. In fact there are more rules on drones than there are on balloons carrying less than four pounds of payload!
While some balloons are designed to pop when they reach a certain altitude, others can float for months, even years at a time. Take for example the amateur radio W5KUB balloons.
The W5KUB-112 balloon has floated around the world 10 times in less than a year aloft! It is currently in the Pacific Ocean south of Alaska and will be re-entering US airspace shortly. Its altimeter reports its position at 47,734 feet – slightly above commercial air traffic but not by much.
This balloon would almost certainly now be on NORAD’s target list given that similar small objects were shot down by US jets at similar altitudes. And while W5KUB is operating these balloons in accordance with US law, they don’t have to register the balloon with authorities so NORAD would likely not know this is a benign payload.
There are likely hundreds of balloons like this floating around the globe carried by the wind. Their payloads could be dead but the balloons themselves may very well still be floating. Adversaries can take advantage of this information gap by floating small payload balloons that look like all of the other stuff floating around in the wind.
Electronics don’t have to be large to be useful spying tools. A small radio like the ones on W5KUB’s balloons could be equipped to dump data to passing satellites via VHF or UHF bands and smaller messages can be sent over the HF bands without a satellite at all.
A few months ago I demonstrated sending data packets up to the space station using a small 7 watt radio.
W5KUB’s small payload transmits APRS positioning packets on VHF frequencies and weak WSPR signals on HF. Those WSPR signals can be picked up even when the balloon is in the middle of the ocean.
Clearly up until now NORAD was looking for planes and missiles. For its part the FAA doesn’t seem to care much about small payload balloons and hasn’t been tracking their movements.
What’s next? I expect to see the FAA clamp down on domestic balloon activity similar to what they did with drones. Further there may be some discussion with other governments to develop some standards around registration and tracking for balloons that have the capability to float beyond borders.