The Lockheed Spyplane That Briefly Made More Liquid Hydrogen Than Anywhere Else In America

Engineers have long seen hydrogen as offering a range of attractive benefits over traditional kerosene jet fuel for aircraft. However, hydrogen has very low energy density by volume, meaning that storing enough of it requires significantly more space than conventional aviation fuel. One of the most remarkable aircraft that never flew was Lockheed’s effort in the 1950s to develop a hydrogen-fueled successor to the Lockheed U-2 spy plane. To accommodate the hydrogen, however, the aircraft was to be enormous.