Freeze-dried ice cream
Freeze dried ice cream, is ice cream that has been freeze dried.
A major type is astronaut ice cream or space ice cream, typically a slab of dehydrated ice cream that is always ready to eat, with no need for refrigeration. Compared to regular ice cream it can be kept at room temperature without melting, and is more brittle and rigid but still soft when bitten into. It was developed by Whirlpool Corporation under contract to NASA for the Apollo missions.[1] [2] Freeze-dried foods were developed so that foods could be sent on long-duration spaceflights, as to the Moon, and to reduce the weight of the water and oxygen normally found in food.[1]
Apollo 7 in 1968 was the first NASA mission on which space ice cream flew in outer space.[3] [4] According to one NASA food scientist, although freeze-dried ice cream was developed on request, "it wasn't that popular."[5] NASA has made available in space-friendly form the top five requested foods: Shrimp cocktail, lemonade, steak, M&M's, and brownies.[6]
This original space ice cream was a specially made food developed by U.S. Army Natick Laboratories, consisting of "coconut fat, milk solids, and sugar was homogenized, frozen, then freeze-dried, ground and compressed into cubes under high pressure. The cubes were then coated with an edible gelatin coating to prevent crumbs".[6] This was the ice cream flown on Apollo 7, which can differ from modern space ice cream.[6]
By 1972 astronauts also ate classic ice cream on the Skylab space station and regular ice cream has also been eaten on the International Space Station.[7] Skylab had a refrigerator that was used for real ice cream,[8] and occasionally Space Shuttle and International Space Station astronauts have taken real ice cream into space.[9]
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 partial 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 freeze-dried ice cream slice.
Freeze-dried ice cream is sold by mail order and is common in science museums and NASA visitor center gift shops, sometimes accompanied by other freeze-dried foods.
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[edit] References
- ^ a b "Space Food" (PDF). NASA. http://lsda.jsc.nasa.gov/lsda_data/nra_research_data/1994_space_food.pdf. Retrieved 2007-06-07. The license is now held by Action Products International, Inc.
- ^ Astronaut Ice Cream
- ^ Thompson, Gregory L. Vogt ; illustrations by Colin W. (2010). Is there life on other planets? and other questions about space. Minneapolis, MN: Lerner Publications. ISBN 0761359451.
- ^ "NASA Spinoff homepage". NASA. http://www.sti.nasa.gov/tto/. Retrieved 2007-06-07.
- ^ "A Holiday Dinner in Space". NASA. December 15, 2005. http://www.nasa.gov/audience/foreducators/k-4/features/F_Holiday_Dinner_in_Space_prt.htm. Retrieved 2009-08-13.
- ^ a b c NASA FTCSC Kid's Page Terrestrial Trivia (answer section)
- ^ Surprise! Astronauts Eat in orbit
- ^ "History of Food in Space". NASA. Archived from the original on 2007-05-26. http://web.archive.org/web/20070526183320/http://liftoff.msfc.nasa.gov/academy/astronauts/food-history.html. Retrieved 2007-06-07.
- ^ "Orbital Ice Cream, Atlantis’ ISS Surprise". LiveScience.com. 2006-09-16. http://www.livescience.com/blogs/2006/09/16/orbital-ice-cream-atlantis-iss-surprise/. Retrieved 2007-06-07.
