CHEBOYGAN, Mich. –The U.S. Coast Guard and Canadian Coast Guard together have embarked on a lake-bottom search of Lake Huron for wreckage of a balloon that was shot out of the sky by a Minnesota Air National Guard warplane. The balloon was punctured by a missile fired from the Minnesota plane at 20,000 feet. In Washington the Pentagon said it doesn’t know who launched the balloon or its mission, but like other recent balloon shoot-downs, it had been in the vicinity of major defense installations. The Michigan Peninsula. for example, has several U.S. Air Force radar stations designed to detect a polar attack over Canada. Also, Michigan is home to many defense industry manufacturers.

Earlier: Walz: Balloon shoot-down “flawless”

Earlier: Minnesota F-16 downs latest mystery balloon

Recent shoot-downs

> February 4: Myrtle Beach, South Carolina, offshore in Atlantic Ocean.

> February 10: Deadhorse, Alaska, on Prudhoe Bay on the Arctic Ocean.

> February 11: Old Crow Flats, Yukon Territory, in a remote interior area about 50 miles from the Alaska border.

> February 12 :Cheboygan, Michigan, in Lake Huron off the Upper Peninsula..