Man discovers piece of Mir space station in Massachusetts river

Phil Green holds a piece of the Mir space station that he discovered along the Merrimack River six years ago. (CBS Boston)

Next time you go fishing, don't be surprised if you catch more than just a fish.

A Massachusetts man was walking along the Merrimack River when a strange-looking rock caught his attention.

"There she was just sitting there, sticking up like that, and I said heck what is this," Phil Green told CBS Boston. "It just didn't belong."

Green knew there was something different about the greenish rock he discovered but it took him six years to contact a friend who worked for NASA to further investigate.

NASA confirmed that Green's "rock" was actually a small piece of the Russian space station Mir.

Mir went up to space in 1986 and returned to earth in 2001. It is unclear how many rogue pieces of Mir exist, but most of the space station landed in the South Pacific.

A custodian at Amesbury Elementary School, Green brought in the piece for show and tell.

"I had a lot of fun taking it to school and showing it to all the kids," he said.

The "rock" is Green's most prized possession and sits in his house alongside a letter from NASA.