He developed a “memory” foam from a polyurethane compound that had what is now called berry unusual visco-elastic properties. Visco stands for the memory of the foam and elastic refers to its ability to mold to whatever it is touching. This new substance was adapted and incorporated into the seating for long airline flights. It created an even body distribution and equalized the pressure over all body areas in contact with the foam. The foam returned to its original shape once the pressure was removed.
Yost formed a company called Dynamic Systems to market the temper foam in 1969 and sold the rights to the product in 1974. They returned to the market offering newer iterations of the product that were more friendly for the environment and less offensive to the consumer. The manufacturing process involved many chemicals that can cause severe allergic reactions in certain individuals and the pouring process creates waste gasses that are harmful to the ozone layer.
The majority of Dynamic Systems sales currently come from the medical markets (eighty percent). They make medical cushions and seating for the severely disabled. They have developed an extremely soft version of temper foam called Pudgee that generates less friction and pressure on tender areas of skin. It is great for wound patients and patients with mostly healed burn areas. They have combined this with their Sunmate product that provides the excellent cushioning with proper stability for support. This combination product is available for wheel chairs to aid those with muscular issues or posture issues that can be aided by the additional support.
All of this from the development of a NASA memory foam mattress. The only company that even vaguely acknowledges that their business stems from the original NASA need for cushioning is Tempur-Pedic and they refer to it obliquely