Decisions to shoot down multiple unidentified objects over the United States and Canada this month have put a spotlight on amateur balloonists who insist their creations pose no threat.
Over the last three weeks, US President Joe Biden has ordered fighter jets to shoot down three objects detected in US airspace — a suspected Chinese spy balloon off the South Carolina coast, as well as smaller unidentified objects over Alaska and Lake Huron.
Canadian Prime Minister Justin Trudeau last week ordered another object to be shot down over the Yukon; a US fighter jet carried out that mission.
US government officials have yet to definitively identify the
objects, but Biden said on Thursday that they were probably balloons linked to private companies, weather researchers or hobbyists.
Tom Medlin, the owner of the Tennessee-based Amateur Radio Roundtable podcast and a balloon hobbyist himself, said he has been in contact with an Illinois club that believes the object shot down over the Yukon was one of their balloons.
The incidents have left balloonists scrambling to defend their hobby.
They insist their balloons fly too high and are too small to pose a threat to aircraft, and that government officials are overreacting.
"The spy balloon had to be shot down," Medlin said. "That's a national security threat, for sure. Then what happened is, I think, the government got a little anxious."
White House National Security Council spokesman John Kirby said the debris had yet to be recovered and "we all have to accept the possibility that we may not be able to recover it".
Kirby pushed back at the notion that Biden's decision to use missiles costing hundreds of thousands of dollars to shoot down what were most likely balloons that cost less than US$20, was an overreaction.
Medlin said the balloons he's flying right now cost about
US$12 and are about 81cm in diameter.
The balloons carry solar-powered transmitters that weigh less than 2g and that broadcast a signal every 10 minutes or so that ham radio operators around the world can use to track the balloons' locations, he said.
He said he has a balloon up right now that's been in the air for 250 days and has circled the globe 10 times.
"The fun is watching the balloon circle the globe and building the tiny transmitters," said Medlin, adding that the devices were so small that he needed a microscope to construct them.
The National Oceanic and Atmospheric Administration had been collecting data from ham radio operators to track wind patterns, he said.
He said the balloons were so light that the Federal Aviation Administration (FAA) did not regulate them and did not require balloonists to file flight plans.
He inflates his balloons with enough hydrogen to ensure they'll fly at about 15,200m.That is well above most commercial aircraft, he said.
Current regulations posted on the FAA's website state that no one can operate an unmanned balloon in a way that creates a hazard, and agency regulations apply only to balloons that carry a payload of more than 1.8kg.
Medlin speculated that after US officials detected the suspected Chinese balloon, they adjusted their radar to pick up very small objects. But the hobbyists' balloons did not pose a threat to aircraft, he said.
Ron Meadows co-founded San Jose-based Scientific Balloon Solutions with his son, Lee. He said the company produced balloons as large as 259cm in diameter for university and middle school science students.
He said those balloons carried a payload of around 10g to 20g with transmitters the size of a popsicle stick.
Some balloons featured a 6m antenna, he said.
He said he had tried to contact the US Department of Homeland Security and the Department of Defence to educate officials about the balloons, but that his calls went to voicemail.
Meadows anticipates that after this month's incidents, the FAA will come out with tighter restrictions on balloons.
Medlin said balloons could reach speeds of up to 210kph if they get caught up in the jet stream.
But Bob Boutin, a Chicago flight instructor, said it was unlikely that such balloons posed much of a threat to aircraft.
Some corporate jets climbed higher than 15,200m, Boutin said.
The writers are from the Associated Press news agency