The epic attempts to power planes with hydrogen

[Jilly_in_VA]

Few of the thousands of tourists who visit West Palm Beach, Florida, every year for its beaches notice the abandoned industrial site on the edge of town. A faded sign reading "CAMERAS FIREARMS NOT PERMITTED ON THIS PROPERTY" was attached to a gate blocking a forgotten access road. It was one of the few clues that the Apix Fertilizer factory once hid a secret.

The 10-square-mile (25.9 sq km) site was a clandestine government facility that, in the late 1950s, was at the heart of American efforts to spy on the Soviet nuclear arsenal.

Rather than producing fertiliser for farmers, the site was probably the world’s largest producer of liquid hydrogen, which was needed for one thing: Project Suntan. This was the code name given to the "beyond top-secret" project to build the replacement for the Lockheed U-2 spy plane, which began in 1956.

The Lockheed CL-400 Suntan was more like a space plane, or a Thunderbird, than a spy plane. Led by Lockheed's genius designer and secretive Skunk Works founder Kelly Johnson, the dartlike flying machine was intended to fly at Mach 2.5 at 30,000m (100,000ft) with a skin temperature of 177ºC (350ºF), have a range of 4,800km (3,000 miles) and be powered by liquid hydrogen – that is, hydrogen cooled down to cryogenic temperatures of around -423ºF (-253C). The Skunk Works, based in Burbank California, was a business-within-a-business that was free of the usual corporate oversight.

https://www.bbc.com/future/article/20220316-the-epic-attempts-to-power-planes-with-hydrogen