The Canadian balloon was last night being guarded by Finnish police until it could be dismantled.
The 100m high helium-filled balloon was launched by Scientific Instrumentation on 24 August to measure the ozone levels of over Canada. But the instrument package failed to jettison and it began an erratic journey.
Canadian, British and American aircraft tracked the runaway balloon and air traffic controllers had to divert planes from its path. Canadian jet fighters fired more than 1,000 rounds at it, but it remained stubbornly aloft.
Last Saturday it disappeared from radar screens about 200 miles north of the Arctic Circle.
Air traffic controllers in northern Norway briefly spotted it over the Svalbard Islands on Sunday before it vanished once again.
It finally reappeared on Tuesday, in Finnish airspace, about 330 miles north-east of Helsinki.
"We had no idea it was the runaway Canadian balloon," said Colonel Pekka Tuunanen from the Finnish Air Force. "Our jets checked it out, and we monitored it until it landed in the Aland islands."
The balloon is used to observe weather patterns and can be seen from about 40 miles away, but it is not equipped with transponders that emit navigation signals to alert aeroplanes to its presence.Reuse content