Astronaut ice cream
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Astronaut Ice Cream, also called Freeze-dried ice cream was developed by NASA for the Apollo missions and is still used today.
It is a dehydrated brick of ice cream that is always ready to eat, with no need to freeze. Freeze drying (or lyophilization), removes water from the ice cream by lowering the air pressure to a point where ice shifts from a solid to a gas. The ice cream is placed in a vacuum chamber and frozen until the water crystallizes. The air pressure is lowered, creating a vacuum, forcing air out of the chamber; next heat is applied, vaporizing the ice; finally a freezing coil traps the vaporized water. This process continues for hours, resulting in a perfect freeze-dried ice cream slice.
Initially, freeze dried ice cream feels like a foamy piece of chalk in your mouth, but your saliva dissolves it quickly; the fats from the ice cream coat the inside of your mouth. The original flavors, usually vanilla, strawberry, and chocolate, arranged as in neapolitan ice cream, are detectable, but not strong.
Astronaut ice cream is ubiquitous in science museum giftshops, sometimes accompanied by other freeze-dried foods such as ice-cream sandwiches, various sliced fruits, and even pizza.
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