With liquid oxygen and hydrogen, stored deep in its hold, this jumbo jet would soar, with a story yet untold. With drop tanks and a space vehicle, attached to its back, this bird would fly to the stars, on a mission to track.
But alas, its performance, and daunting tech on display, the concept never took off, and quietly flew away. But in the annals of history, it lives on in the mind, a dream of what could have been, a rocket of a different kind.
In the 1960s, Lockheed and the U.S. Air Force’s Flight Dynamics Laboratory (FDL) explored several design concepts for hypersonic flight. Three principal vehicles, the FDL-5, FDL-6 and FDL-7, were based on 70-degree triangles and had different designs.
The FDL-5 had variable-geometry wings for controlled landings, and one proposal called for it to be carried aloft by a C-5 Galaxy transport and then released at high altitude. The Air Force Rocket Propulsion Laboratory also outlined an “Air Force Sortie Space System” that had three major parts: a launch platform, drop tanks, and a space vehicle, which was a 747 with liquid oxygen and liquid hydrogen storage tanks inside its fuselage and hydrogen pumped into afterburners for thrust augmentation. Another option involved a vehicle sized to fit inside the shuttle bay.