NASA's big B-52B jet dropped more aircraft than bombs during an aerial career that spans nearly five decades, but hung up its wings for good this month.

The space agency officially retired the hulking, eight-engine jet plane, which served as an aircraft mothership for hundreds of experimental flights throughout the years, on Dec. 17.

First put into service by the U.S. Air Force to test bomb navigation systems, the B-52B - better known by its tail numbers 008 - began its career in June of 1955. By 1959 the aircraft became one of two airborne motherships for the X-15 program, clutching test aircraft close under one wing until reaching a desired altitude, then turning loose the experimental plane and its pilot.

With the end of X-15 program in 1969, the carrier aircraft served as the go-to mothership for any NASA test flight requiring air launch at the agency's Dryden Flight Research Center. It tested parachutes that would later be used on NASA's space shuttles and solid rocket boosters, and eventually dropped unpowered, wingless lifting bodies which proved gliding vehicles like the shuttle could return to Earth safely.

The aircraft's final flight - hoisting NASA's hypersonic X-43A test vehicle on a flight that would not only prove successful but propel the experimental scramjet aircraft at speeds of nearly Mach 10 - took place on Nov. 16, 2004.

This image shows NASA's B-52B in its early days under the space agency's employ. Taken from a chase plane in 1972, this image captures the moment just after an experimental lifting body has cut loose from the B-52B mothership and begun the flight away from its parent.

-- SPACE.com Staff

Credit: NASA/Dryden Flight Research Center