10/31/2007. Remarks by Jack McKillop: "This aircraft was ordered by the USN as a Model 1049B-55-75 cargo-transport that could carry 73 to 106 passengers and eight crew. It was delivered on October 31, 1953 designated R7V-1, BuNo. 131642 and assigned to Transport Squadron Eight (VR-8) based at Hickam AFB, Territory of Hawaii.

On December 7, 1956, the Secretary of Defense ordered that the USAF be designated as the single manager for airlift services with the USAF's Military Air Transport Service (MATS) as the principal agency for airlift needs. As a result VR-8 moved to NAS Moffett Field, Mountain View, California, in August 1957 and in June 1958, the R7Vs were transferred to the Air Force and redesignated C-121Gs but were operated by Navy crews. This aircraft became a C-121G-LO, USAF s/n 54-4065 named City of San Francisco and assigned to the Western Transport Air Force (WESTAF), MATS.

In September 1963, this aircraft was leased to the NASA and based at Friendship Airport, Baltimore, Maryland. Coded NASA "20", the aircraft was assigned to the Goddard Space Center and was stripped and instrumented with Mercury, Gemini, Agena and Apollo spacecraft equipment and test gear. Its task was to perform engineering evaluation and operations readiness tests at the manned space-flight tracking stations around the world. Between May and October 1966, this Connie was based at Northwest Cape Space Tracking Station in Western Australia.

Upon returning to the US, this C-121 was recoded NASA "420" and eventually registered N420NA in June 1969. In January 1973, NASA withdrew this aircraft from service and transferred it to the US Army Proving Grounds at Aberdeen, Maryland, where it was used as a target for testing explosive devices on aircraft structures. It had 18,667 hours on the airframe at this time. The airframe was put up for sale on August 23, 1978 and was later scrapped."