Navy pays tribute to once-secret submarine now on display at Connecticut museum

A submarine that was among the most secretive vessels in the U.S. undersea force has been put on display at the Navy's Submarine Force Library and Museum in Groton.

Adm. Jonathan Greenert, chief of naval operations, spoke to a gathering Wednesday in front of a portion of the tiny NR-1 submarine that was launched in 1969. He was engineer of the nuclear-powered NR-1.

Greenert called it a "technical marvel" that expanded knowledge of engineering and technology. He said the sub made ocean floor exploration possible.

He credited industry, specifically NR-1 maker Electric Boat, with making it possible for the U.S. to own the undersea domain.

The NR-1 was used in expeditions, including recovering parts of the Challenger shuttle destroyed in 1986. It was taken out of service in 2008.