Jump to content

Space blanket: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous edit
Content deleted Content added
VisualWikitext
Removed image because the text is italian and additionally it suggestes using a space blanket for hyperthermia as well as hypothermia, which directly contradicts the article.
→Popular references: So very important, especially without any source
 
(25 intermediate revisions by 25 users not shown)
Line 2: Line 2:
[[Image:RescueFoil.jpg|thumb|A space blanket]]
[[Image:RescueFoil.jpg|thumb|A space blanket]]
{{Short description|Aluminized plastic sheet used to protect against heat in space}}
{{Short description|Aluminized plastic sheet used to protect against heat in space}}
A '''space blanket''' (also known as a [[BoPET|Mylar]] blanket, emergency blanket, first aid blanket, safety blanket, thermal blanket, weather blanket, heat sheet, or shock blanket) is an especially low-weight, low-bulk [[blanket]] made of heat-reflective, thin, plastic sheeting. They are used on the exterior surfaces of spacecraft for thermal control, as well as by people. Their design reduces the heat loss in a person's body, which would otherwise occur due to thermal radiation, water evaporation, or convection. Their low weight and compact size before unfurling make them ideal when space or weight are at a premium. They may be included in [[first aid kit]]s and with camping equipment. Lost campers and hikers have an additional possible benefit: the shiny surface flashes in the sun, allowing its use as an improvised [[distress beacon]] for [[search and rescue|searchers]] and as a method of signalling over long distances to other people.<ref>{{cite web|url=https://adventure.howstuffworks.com/survival/gear/space-blanket.htm|title=How Space Blankets Work|date=24 November 2009|website=howstuffworks.com|access-date=14 September 2018}}</ref>
A '''space blanket''' (also known as a '''[[BoPET|Mylar]] blanket''', '''emergency blanket''', '''first aid blanket''', '''safety blanket''', '''thermal blanket''', '''weather blanket''', '''heat sheet''', '''foil blanket''', or '''shock blanket''') is an especially low-weight, low-bulk [[blanket]] made of [[radiant barrier|heat-reflective]] thin plastic sheeting. They are used on the exterior surfaces of spacecraft for thermal control, as well as by people. Their design reduces the heat loss in a person's body, which would otherwise occur quickly due to thermal radiation, water evaporation, or convection. Their low weight and compact size before unfurling make them ideal when space or weight are at a premium. They may be included in [[first aid kit]]s and with camping equipment. Lost campers and hikers have an additional possible benefit: the shiny surface flashes in the sun, allowing its use as an improvised [[distress beacon]] for [[search and rescue|searchers]] and as a method of signalling over long distances to other people.<ref>{{cite web|url=https://adventure.howstuffworks.com/survival/gear/space-blanket.htm|title=How Space Blankets Work|date=24 November 2009|website=howstuffworks.com|access-date=14 September 2018}}</ref>


==Manufacturing==
==Manufacturing==
Line 21: Line 21:
the material comprises a thin sheet of [[plastic]] (often [[PET film (biaxially oriented)|PET film]]) that is coated with a [[metal]]lic, [[Reflection (physics)|reflecting]] agent, making it [[metallized polyethylene terephthalate]] (MPET) that is usually gold or silver in color, which reflects up to 97% of [[thermal radiation|radiated]] heat.<ref>[https://web.archive.org/web/20030810193711/http://www.insul.net/testdata.html Reflective Insulation Test data].</ref><ref>{{cite web|url=http://www.traditionalmountaineering.org/FAQ_SpaceBlankets.htm|title=Emergency space blankets provide a false sense of security|first=Robert|last=Speik|website=traditionalmountaineering.org|access-date=14 September 2018}}</ref>
the material comprises a thin sheet of [[plastic]] (often [[PET film (biaxially oriented)|PET film]]) that is coated with a [[metal]]lic, [[Reflection (physics)|reflecting]] agent, making it [[metallized polyethylene terephthalate]] (MPET) that is usually gold or silver in color, which reflects up to 97% of [[thermal radiation|radiated]] heat.<ref>[https://web.archive.org/web/20030810193711/http://www.insul.net/testdata.html Reflective Insulation Test data].</ref><ref>{{cite web|url=http://www.traditionalmountaineering.org/FAQ_SpaceBlankets.htm|title=Emergency space blankets provide a false sense of security|first=Robert|last=Speik|website=traditionalmountaineering.org|access-date=14 September 2018}}</ref>


For use in space, [[polyimide]] (e.g. [[kapton]], [[UPILEX]]) substrate is usually chosen due to its resistance to the hostile [[corrosion in space|space environment]], large temperature range (cryogenic to −260&nbsp;°C and for short excursions up to over 480&nbsp;°C), low [[outgassing]] (making it suitable for [[Materials for use in vacuum|vacuum use]]), and resistance to [[ultraviolet]] radiation. Aluminized [[kapton]], with foil thickness of 50 and 125&nbsp;µm, was used on the [[Apollo Lunar Module]].<ref>{{cite web|url=http://home.earthlink.net/~pfjeld/lmdata/index.html|title=Lunar Module Coatings|author=Paul Fjeld|website=home.earthlink.net|access-date=14 September 2018}}</ref> The polyimide gives the foils their distinctive amber-gold color.
For use in space, [[polyimide]] (e.g. [[Kapton]], [[UPILEX]]) substrate is usually chosen due to its resistance to the hostile [[corrosion in space|space environment]], large temperature range (cryogenic to −260&nbsp;°C and for short excursions over 480&nbsp;°C), low [[outgassing]] (making it suitable for [[Materials for use in vacuum|vacuum use]]), and resistance to [[ultraviolet]] radiation. Aluminized [[Kapton]], with foil thickness of 50 and 125&nbsp;μm, was used on the [[Apollo Lunar Module]].<ref>{{cite web|url=http://home.earthlink.net/~pfjeld/lmdata/index.html|title=Lunar Module Coatings|author=Paul Fjeld|website=home.earthlink.net|access-date=14 September 2018}}</ref> The polyimide gives the foils their distinctive amber-gold color.


Space blankets are made by [[vacuum deposition|vacuum-depositing]] a very precise amount of pure [[aluminum]] vapor onto a very thin, durable film substrate.<ref>{{cite web| url =https://sustainableplanet.ca/best-weighted-blankets-canada/ | title =Space Blankets | access-date = 12 March 2016}}</ref>
Space blankets are made by [[vacuum deposition|vacuum-depositing]] a very precise amount of pure [[aluminum]] vapor onto a very thin, durable film substrate.<ref>{{cite web| url =https://sustainableplanet.ca/best-weighted-blankets-canada/ | title =Space Blankets | access-date = 12 March 2016}}</ref>
Line 35: Line 35:
* The [[Reflection (physics)|reflective]] surface inhibits losses caused by [[thermal radiation]]
* The [[Reflection (physics)|reflective]] surface inhibits losses caused by [[thermal radiation]]


In a hot environment, they can be used to provide shade or protection against radiated heat, but using them to wrap a person would be counterproductive, because [[body heat]] would get trapped by the airtight foil. This effect would exceed any benefit gained from heat reflection to the outside. Wearing a space blanket produces an insignificantly slower cooling rate after running in hot, humid conditions.<ref>{{cite journal|title=Reflective Blankets Do Not Effect Cooling Rates after Running in Hot, Humid Conditions|first1=KORY|last1=REYNOLDS|first2=JOHN|last2=EVANICH|date=2015|journal=Int J Exerc Sci.|volume=72|issue=4|pages=393–6|doi=10.1093/bja/72.4.393|pmid=8155437|pmc=4831857}}</ref>
In a hot environment, they can be used to provide shade or protection against radiated heat, but using them to wrap a person would be counterproductive, because [[body heat]] would get trapped by the airtight foil. This effect would exceed any benefit gained from heat reflection to the outside. Wearing a space blanket produces an insignificantly slower cooling rate after running in hot, humid conditions.<ref>{{cite journal|title=Reflective Blankets Do Not Effect Cooling Rates after Running in Hot, Humid Conditions|first1=KORY|last1=REYNOLDS|first2=JOHN|last2=EVANICH|date=2015|journal=Int J Exerc Sci|volume=72|issue=4|pages=393–6|doi=10.1093/bja/72.4.393|pmid=8155437|pmc=4831857}}</ref>


Space blankets are used to reduce heat loss from a person's body, but as they are constructed of [[BoPET|PET film]], they can be used for other applications for which this material is useful, such as insulating containers (e.g. DIY solar projects) and other applications.
Space blankets are used to reduce heat loss from a person's body, but as they are constructed of [[BoPET|PET film]], they can be used for other applications for which this material is useful, such as insulating containers (e.g. DIY solar concentrators) and other applications.


In addition to the space blanket, the [[United States military]] also uses a similar blanket called the "casualty blanket". It uses a thermal reflective layer similar to the space blanket, backed by an [[olive drab]]-colored, reinforcing, outer layer. It provides greater durability and warmth than a basic space blanket at the cost of greater bulk and weight. It is also used as a partial liner inside the layers of bivouac sacks in very cold weather climates.<ref>{{cite web|url=http://www.rei.com/expertadvice/articles/bivy+sack.html|title=How to Choose Bivy Sacks|website=REI|access-date=14 September 2018}}</ref> Space blankets are also used by the [[Taliban]] to hide their heat signature from NATO forces.<ref>{{cite web |url=https://www.bbc.co.uk/news/world-south-asia-16026965 |publisher=[[BBC]] |title=Afghanistan: Patrolling the most attacked base |date=5 December 2011 |access-date=5 December 2011}}</ref><ref>Smucker, Philip. [http://www.thestate.com/166/story/811102.html "U.S. soldiers' options limited to protect Afghans from Taliban."] The State. Jun. 2, 2009.</ref>
In addition to the space blanket, the [[United States military]] also uses a similar blanket called the "casualty blanket". It uses a thermal reflective layer similar to the space blanket, backed by an [[olive drab]]-colored, reinforcing, outer layer. It provides greater durability and warmth than a basic space blanket at the cost of greater bulk and weight. It is also used as a partial liner inside the layers of bivouac sacks in very cold weather climates.<ref>{{cite web|url=http://www.rei.com/expertadvice/articles/bivy+sack.html|title=How to Choose Bivy Sacks|website=REI|access-date=14 September 2018}}</ref> Space blankets were also used by the [[Taliban]] to hide their heat signature from NATO forces.<ref>{{cite web |url=https://www.bbc.co.uk/news/world-south-asia-16026965 |publisher=[[BBC]] |title=Afghanistan: Patrolling the most attacked base |date=5 December 2011 |access-date=5 December 2011}}</ref><ref>Smucker, Philip. [http://www.thestate.com/166/story/811102.html "U.S. soldiers' options limited to protect Afghans from Taliban."] The State. Jun. 2, 2009.</ref>


==See also==
==See also==

Latest revision as of 13:10, 15 August 2024

"Emergency blanket" redirects here. For the Peruvian rock band, see Emergency Blanket (band).
A space blanket

A space blanket (also known as a Mylar blanket, emergency blanket, first aid blanket, safety blanket, thermal blanket, weather blanket, heat sheet, foil blanket, or shock blanket) is an especially low-weight, low-bulk blanket made of heat-reflective thin plastic sheeting. They are used on the exterior surfaces of spacecraft for thermal control, as well as by people. Their design reduces the heat loss in a person's body, which would otherwise occur quickly due to thermal radiation, water evaporation, or convection. Their low weight and compact size before unfurling make them ideal when space or weight are at a premium. They may be included in first aid kits and with camping equipment. Lost campers and hikers have an additional possible benefit: the shiny surface flashes in the sun, allowing its use as an improvised distress beacon for searchers and as a method of signalling over long distances to other people.[1]

Manufacturing

[edit]
layering materials of emergency blanket
layering materials of emergency blanket
32 layers are 0.45mm thick

First developed by NASA's Marshall Space Flight Center in 1964 for the US space program,[2][3][4] the material comprises a thin sheet of plastic (often PET film) that is coated with a metallic, reflecting agent, making it metallized polyethylene terephthalate (MPET) that is usually gold or silver in color, which reflects up to 97% of radiated heat.[5][6]

For use in space, polyimide (e.g. Kapton, UPILEX) substrate is usually chosen due to its resistance to the hostile space environment, large temperature range (cryogenic to −260 °C and for short excursions over 480 °C), low outgassing (making it suitable for vacuum use), and resistance to ultraviolet radiation. Aluminized Kapton, with foil thickness of 50 and 125 μm, was used on the Apollo Lunar Module.[7] The polyimide gives the foils their distinctive amber-gold color.

Space blankets are made by vacuum-depositing a very precise amount of pure aluminum vapor onto a very thin, durable film substrate.[8]

Infrared spectroscopy emergency blanket

Usage

[edit]

In their principal usage, space blankets are included in many emergency, first aid, and survival kits because they are usually waterproof and windproof. That, along with their low weight and ability to pack into a small space, has made them popular among outdoor enthusiasts and emergency workers. Space blankets are often given to marathoners and other endurance athletes at the end of races, or while waiting before races if the weather is chilly.[9] The material may be used in conjunction with conductive insulation material and may be formed into a bag for use as a bivouac sack (survival bag).[10][11]

In first aid,[12] the blankets are used to prevent or counter hypothermia. A threefold action facilitates this:

In a hot environment, they can be used to provide shade or protection against radiated heat, but using them to wrap a person would be counterproductive, because body heat would get trapped by the airtight foil. This effect would exceed any benefit gained from heat reflection to the outside. Wearing a space blanket produces an insignificantly slower cooling rate after running in hot, humid conditions.[14]

Space blankets are used to reduce heat loss from a person's body, but as they are constructed of PET film, they can be used for other applications for which this material is useful, such as insulating containers (e.g. DIY solar concentrators) and other applications.

In addition to the space blanket, the United States military also uses a similar blanket called the "casualty blanket". It uses a thermal reflective layer similar to the space blanket, backed by an olive drab-colored, reinforcing, outer layer. It provides greater durability and warmth than a basic space blanket at the cost of greater bulk and weight. It is also used as a partial liner inside the layers of bivouac sacks in very cold weather climates.[15] Space blankets were also used by the Taliban to hide their heat signature from NATO forces.[16][17]

See also

[edit]

References

[edit]
  1. ^ "How Space Blankets Work". howstuffworks.com. 24 November 2009. Retrieved 14 September 2018.
  2. ^ Hall, Loura (15 September 2016). "Reflecting on Space Benefits: A Shining Example". NASA Center for AeroSpace Information. Archived from the original on 2 February 2007. Retrieved 14 September 2018.
  3. ^ Huntington, Tom. "Bringing NASA Down to Earth." AmericanHeritage.com. 2008.
  4. ^ Bryan, Will (May 11, 2016). "The Space Blanket: Your Adventure Companion". The Marshall Star. NASA. Retrieved May 11, 2016.
  5. ^ Reflective Insulation Test data.
  6. ^ Speik, Robert. "Emergency space blankets provide a false sense of security". traditionalmountaineering.org. Retrieved 14 September 2018.
  7. ^ Paul Fjeld. "Lunar Module Coatings". home.earthlink.net. Retrieved 14 September 2018.
  8. ^ "Space Blankets". Retrieved 12 March 2016.
  9. ^ "General Guidelines for Recycling at Mass Participant Sporting Events." AFMInc. 2008.
  10. ^ "Emergency Shelter" REI.
  11. ^ "Full Wrap on Space Blankets." Runner's World. 2005.
  12. ^ Buggy, D.; Hughes, N. (1 April 1994). "Pre-emptive use of the space blanket reduces shivering after general anaesthesia". British Journal of Anaesthesia. 72 (4): 393–396. doi:10.1093/bja/72.4.393. PMID 8155437.
  13. ^ "How Body Heat is Lost." Survival Topics.
  14. ^ REYNOLDS, KORY; EVANICH, JOHN (2015). "Reflective Blankets Do Not Effect Cooling Rates after Running in Hot, Humid Conditions". Int J Exerc Sci. 72 (4): 393–6. doi:10.1093/bja/72.4.393. PMC 4831857. PMID 8155437.
  15. ^ "How to Choose Bivy Sacks". REI. Retrieved 14 September 2018.
  16. ^ "Afghanistan: Patrolling the most attacked base". BBC. 5 December 2011. Retrieved 5 December 2011.
  17. ^ Smucker, Philip. "U.S. soldiers' options limited to protect Afghans from Taliban." The State. Jun. 2, 2009.
[edit]
Retrieved from "https://en.wikipedia.org/w/index.php?title=Space_blanket&oldid=1240458582"