1966, the folks at NASA wanted to nestle pilots' tushies. Pilots worked hard, they risked their lives, they deserved a happy backside. Some strategic nestling would also protect the tush in a crash or during sudden vibrations.
So NASA called in Charles Yost for the butt-protection project. He had worked with the agency four years earlier on creating a recovery system for the Apollo command module. Back then he invented a whole new material by feeding gas into a polymer matrix. The resulting foam contained billions of open cells that were solid but sometimes acted like liquid. They could shift and reorganize when compressed. Yost called it "slow spring back foam". It was also heat sensitive: the material softened with the heat of the body, and where the material was cooler, it stayed firmer. That meant it had the amazing ability to mould to individuals, distributing weight evenly. No pointy springs gouging into your left cheek. It could even spring back to its original shape after a 90 per cent squish down.
In short, it worked well for butt comfort! NASA developed what they later called "Temper Foam" in the 1970s and installed it in Space Shuttle seats and everything else that needing cushioning.
In 1989, during a ceremony inducting the foam into the Space Hall of Fame, co-inventor Chuck Kubokawa described just how well the stuff cushioned impact: "We crash-tested several seats at the Civil Aeromedical Institute in Oklahoma City to validate them for impact survival, and we found the foam was good for 36 Gs. The seat can out-survive the aircraft in a crash." Just a 3-inch pad of the stuff absorbs the impact of an average adult's 3m fall.
In the early 1980s, NASA released their foam into the public domain. Memory foam for all! Even if you don't own a fancy Tempur-Pedic mattress, you've probably witnessed Temper Foam's special properties, as the stuff's been wrapped into products ranging from shoes to pillows to aeroplanes to football helmets to cars to amusement park rides, horse back saddles, archery targets, furniture and human and animal prostheses... phew!
Since then, engineers have tinkered with the construction and materials to make it even more versatile. When patients are at risk of bed sores, doctors can mod the foam to make it safer. Commercial mattress makers, after customers complained that the mattresses were too hot, found ways to better ventilate the material. Chris Nelson, president of Select Foam, one of many mattress companies that have taken advantage of NASA's innovation, explains that his industry has made the material great for sleeping by adding airflow layers and incorporating other materials, like DuPont's Coolmax fabric, which wicks sweat away from the body. They've also bumped up the material's response time, improving how quickly it will spring back to its original shape. Shoemakers have solved the heat problem by adding an antibacterial layer on top of the foam that similarly diverts heat and moisture. And manufacturers using Temper Foam have also been experimenting with plant-based alternatives to the polyurethane-silicon plastic original.
The biggest bummer: the stuff makes jumping on the bed not nearly as fun -- although, if the Tempur-Pedic adds are true, it might stop your bed-mate from noticing it.