It didn't look "very space-y," said Henry Kline, a spokesman for NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It's obviously made for something ... But we wouldn't know what to do with it."
It didn't appear to be an airplane part either, the FAA said.
Finally, FAA spokesman Jim Peters said Wednesday, a colleague in his office solved the mystery: It was part of a commercial woodchipper. The same part from another woodchipper's grinder had caused similar confusion last year, he said.
How it got on a Bayonne roof was anyone guess, but Peters had a theory. The grinder piece moves very fast and, apparently, it can launch into the air if something goes wrong.
The man who lives in the house was watching television Tuesday when he heard a crash and saw a cloud of dust. In the next room, he found the hunk of gray metal, 3 1/2 inches by 5 inches, with two hexagonal holes in it.
The part was being returned to Bayonne Police on Wednesday, Peters said.
"It belongs to somebody," Police Director Mark Smith said.