The rogue Canadian weather balloon which proved difficult to shoot down.
Twenty-five years later, Dale Sommerfeldt can laugh about the rogue weather balloon that resisted the firepower of air forces from three nations trying to bring it down.
But he admits at the time it was a headache for those involved.
In 1998, a technical malfunction meant the research balloon had failed to come down as planned, in two or three days' time.
Instead, it began to drift across Canada towards the Atlantic Ocean. Mr Sommerfeldt, who works for the Canadian engineering firm Scientific Instrumentation Ltd, which built the instrumentation for the balloon, said it had been meant for "strictly scientific research" related to ozone. The Canadian balloon was a different style from the Chinese balloon shot down over the weekend by the US, he added, noting that "those are intended to stay up for weeks or even a month at a time."
It was a massive thing - the size of a 25-storey building that would cover an area equivalent to five football pitches if deflated, according to a BBC report from the time. The helium-filled balloon was launched from the province of Saskatchewan in late August of 1998, to conduct research for the Canadian Space Agency, Environment Canada and the University of Denver in the US.
But the researchers quickly realised something had gone wrong. A valve that would allow the balloon to naturally release gas and deflate over time had ended up covered by a piece of plastic. It was not long before they had lost control of it.
"The termination device failed and the backup system failed and that's why the balloon is where it is right now,″ Mr Sommerfeldt told the Associated Press news agency in 1998.
On Monday he told the BBC: "It was just subject to whatever the winds were."
An attempt to bring it down was made off the coast of Newfoundland and Labrador, but to no avail. ...