Northrop Grumman Corporation has donated $5,000 toward construction of a memorial to the Navy submarine 'USS Thresher'. The company has made this donation in memory of two employees who perished when the Thresher sank in the Atlantic Ocean 50 years ago. Northrop Grumman Sperry Marine employees Kenneth R. Corcoran and Donald T. Stadtmuller were performing work on the Thresher's gyroscope when the submarine sank during deep-diving tests approximately 200 miles off New England in April 1963. All 129 military crewmen and civilian technicians onboard perished.