The Glenn L. Martin
Maryland Aviation Museum

During the Vietnam War, the Air Force Security Services was interested in an unpiloted aircraft to provide reconnaissance and communications relay that could stay airborne for 28 hours.  Martin Marietta submitted a plane called the 845, based on the Schweizer SGS 1-34 sailplane to which was added a 200hp Lycoming engine.  The program was cancelled in 1972.  Three of the aircraft were built.

 

Two of the Martin Marietta planes were transferred to the Office of Naval Research and then to the Langmuir Laboratory for Atmospheric Research at the New Mexico Institute of Mining and Technology (aka New Mexico Tech).  One plane was lengthened by 29” and a cockpit installed.  This plane (model 845A) was called the SPTVAR, Special Purpose Test Vehicle for Atmospheric Research.  Its role was to fly through thunderstorms and measure atmospheric electrical activity.  The first flight was in May 1957, and the last in August 1992, during which time it logged about 750 flight hours.

 

On July 15, 1975, the SPTVAR provided atmospheric testing over Cape Canaveral prior to the launch of Apollo capsule that participated in the Apollo-Soyuz mission.  Most of its flights were over Florida and New Mexico.

 

The two aircraft are on permanent loan to the Museum.  The piloted one will be reassembled and be on display in The Learning Center in the C basement at Lockheed Martin.