The Aluminum Alloy in the Shuttle's Fuel Tanks Dates to 1954

NASA's guidance on aluminum alloy 2219 traces it to Alcoa, which developed the age-hardenable aluminum-copper alloy in 1954. Its aerospace résumé is broad: launch and space vehicles including space shuttle fuel tanks, along with the human-rated pressurized modules of the International Space Station. The reason sits in the property list. NASA describes 2219 as having excellent cryogenic properties, weldability, workability, and mechanical properties at low and high temperatures. That is a lot of conditions for one alloy family to satisfy at once, which is roughly what spacecraft structures demand of it.