On display at the Museum of Flight. This twin-seat Quiet Star was designed to operate as an observation aircraft to spot night-time activity. It was equipped with a night vision and infrared downward-facing periscope that was operated by the observer in the front seat. The Quiet Star was nearly silent, and this aircraft, one of only 11 built served in Vietnam from 1970-72.

Based on the Schweizer SGS 2-32 glider, the Lockheed QT-2 and YO-3 were designed for silent nocturnal observation missions. Eleven YO-3As were built. Although nine were deployed to Vietnam with some reported success in 1970, no further production followed.

Lockheed developed the "Quiet Star" ultra quiet observation aircraft for the US Army to track night troop and supply movements in Vietnam. 69-18005 was deployed there from 1970-72. Sold to the Special School District of St Louis County, Missouri in 1973, it was acquired by Harold and Vic Hanson of Seattle and rebuilt to flying status, registered N33YQ as a Lockheed-Hansen YO-3A with the FAA. The fairly unique aircraft was sold again in 1987, fully restored and donated to the Museum of Flight in 2014.