With all the advertising about memory foam these days, it's hard to imagine that this material has only been in existence for a little over 30 years.

It's difficult to find an exact date when memory foam first came into being, but it was originally formulated during the early days of manned space flight.

Most likely, it was in the mid to late 1960's.

The National Aeronautics & Space Administration, aka. NASA, needed a material that would cushion the astronauts from the unparalleled g-forces of launch and re-entry during space missions.

In response the their request, a material was produced, called visco-elastic memory foam.

I've seen dozens of articles explaining what visco-elastic memory foam means and none of them has the same explanation.

The online dictionary gives no definition for the word visco, but the word is derived from viscous, which means "gummy or pasty." It is a cross between a solid and a liquid.

I think we all know what elastic means, but, again, the definition is, "being able to return to it's original shape after being deformed."

Well...that's enough of the grammar lesson. The point is that this material hadn't existed before...it's unique.

The whole idea, of showing a picture with a hand print, over the top of a memory foam mattress, is to illustrate that this material isn't forcefully pushing against you.

That's why it takes a while for the memory foam to react and slowly return, to it's original shape, once the hand is removed.

The other quality, of visco elastic memory foam, is that it's temperature reactive. When it's heated, it becomes softer and when it's cooled, it becomes firmer.

A body, laying on the memory foam material, will heat it, making it softer under that heated area.

Again, it's not clear whether or not this earlier version of the memory foam material was ever actually used in any space missions.

Some claim that the material off-gassed, producing an odor that couldn't be tolerated in the small quarters of a spacecraft.

Whatever the reason, this material was too expensive to be used in the form of a memory foam mattress or memory foam pillow for the average consumer.

It was not, however, too expensive for use as an aid to recovery for multi-million dollar racehorses who had been injured or were recovering from surgery.

Horses cut off their circulation when they lay down so when horses are recovering, they need to be in the upright position, so that their blood circulation isn't restricted.