The M2-F2 Lifting Body is shown here being carried aloft by the Air Force's B-52 (tail number 003) prior to a research launch. The success of Dryden's ''homebuilt'' M2-F1 program led to NASA's development and construction of two heavyweight lifting bodies--the M2-F2 and the HL-10, both built by the Northrop Corporation. The ''M'' refers to ''manned'' and ''F'' refers to ''flight'' version. ''HL'' comes from ''horizontal landing.'' The first flight of the M2-F2--which looked much like the ''F1''--was on July 12, 1966. Milt Thompson was the pilot.