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space blankets are also used by a lot of gardeners: they're put down as weed control layers (the plant you want have to grow gets planted through a little hole, insect control (many bugs instinctively go to the bottom of a leaf--if light is relecting up, they can't find the "bottom"), reflecting light in shadier areas, and it's bright and light enough to blow if you hang up strips of it to scare birds. This is common enough that you can often find space blankets sold at garden and farm stores.
These 'blankets' reflect most of your radiated heat. But most of your heat loss is not radiated - it is conducted. Most of that through your exposed extremities like hands and head. Look at extreme mountaineers - they lose fingers and toes to frostbite. Feet get the most conduction to the snow. I never heard of other bits getting frostbite, but that's not a mountaineering story you would bring up eh guys?
I keep reading about space blankets being clever technology, but no hiker I met had much faith in them. Most considered them worse than useless, because people got false feelings of security from their magic hi-tech shiny space blanket. I never heard anyone say "My space blanket was lovely and warm!". Maybe because they died of hypothermia before they could demand a refund.
I considered getting a workmate to take an infra-red photo of me with various amounts of clothing, with and without a space blanket. Apart from being a bit kinky, it is effing cold right now.
I looked around for an alternative guinea pig (not a real one), and noticed my lunch: a hot ooty roll in aluminium foil. Different kind of pig, dead and fried. :-) Space blankets are just very thin aluminium foil, with plastic backing.
I can state that it looked very 'dark' in radiated heat, not surprising as shiny aluminium is not very emissive. Unwrapped a bit, the contents were glowing. So thermal radiation was being reduced.
However, it felt hot to the touch, so conduction was not being reduced. Ten minutes and it had gone from piping hot to lukewarm.SpareHeadOne 23:09, 1 December 2010 (UTC)
I'd have thought this was common sense - I do not know of any source of cold weather clothing that bothers with radiated heat. Everything I have seen involves trapping layers of air next to the body. Nobody wears aluminium foil clothes to keep warm. Space blankets are just very thin aluminium film on a plastic sheet. You can easily prove how ineffective it is by wrapping yourself in foil (or plastic sheet) and going out in the cold. SpareHeadOne 23:09, 1 December 2010 (UTC)
If I say hydrogen burns with a hot flame, that would be acceptable and credible. If I say hydrogen burns at a particular temperature, then I need a source for that figure. If I say hydrogen makes things cold when it burns (contrary to common belief), then I need backup.
It is common knowledge that on Earth, heat loss by conduction and convection is far greater than radiation. The vacuum flask proves this all the time. The glass ones often have silvering to reflect radiated heat, but stainless steel ones don't take silvering like glass. A boiling hot cup of tea in a typical room goes 'cold' in about 10 to 20 minutes. In a vacuum flask, it is still piping hot 8 or 9 hours later.
Do you really need a scientific citation for that?
You might want one for figures on the actual percentages.
Quoting the article: http://en.wikipedia.org/wiki/Vacuum_flask "At the temperatures for which vacuum flasks are used (usually below the boiling point of water), and with the use of reflective coatings, there is little infrared (radiative) transfer"
Thermal radiation is proportional to the 4th power of the absolute temperature. So one can feel heat radiated from something as hot as an electric fire, or light bulb filament if a few inches away. I don't know anyone who can feels warmth radiating from a human. SpareHeadOne 23:09, 1 December 2010 (UTC)
I've seen many claims that space blankets reflect high percentages of body heat(i.e. 80%), but have not seen any scientific literature supporting this, and find it highly questionable if not unlikely. Outdoorvegan 02:41, 23 April 2006 (UTC)
It's interesting to see almost my exact thoughts on this subject. I am a scientist (and climber) and have been considering using a "space blanket" for an ultralight back-country marathon. However, I don't want to be the guinea pig. I suppose I could test the material by using it in my backyard first, but I thought of all things, there would likely be data available. Alas, I have yet to locate any. I imagine the US patent office probably has the original information but I have yet to search there. Count me in for another person looking for real data on the subject.
go to " http://www.mpioutdoors.com/get-tech.htm", It has great space blanket data! —The preceding unsigned comment was added by 24.126.131.48 ( talk) 20:13, 25 April 2007 (UTC).
Blizzard rescue blankets use Reflexcell(TM) ... see Thermal Performance & vs Alternatives, although this source might not be considered Secondary, It does gain good provenance from being a supplier to the UK Military. Exit2DOS2000• T• C• 03:33, 10 October 2008 (UTC) MPIOutdoors is now Grabber Outdoors. It should be noted that "Space Blanket" is a registered trademark of Grabber, Inc. and should be cited appropriately. —Preceding unsigned comment added by 69.129.122.250 ( talk) 15:00, 29 January 2010 (UTC)
FYI- Grabber, Inc. is the owner of "Space Blanket" trademark. Subsequently, this article is improperly cited. — Preceding unsigned comment added by 69.129.122.250 ( talk) 19:22, 7 June 2011 (UTC)
I don't understand the above-indicated contention in the article (marked citation needed currently). If the metalized surface reduces radiative heat loss by reflecting it, then what difference does it make which side is the outer side? The layer will reflect regardless, its not like it disappears if you put it on the outside instead of the inside. Does the article claim it somehow acts as a one way radiation reflector? I could understand its preferred placement on the side of incoming radiation when you wish to wish to use it to prevent radiative energy from raising the temp of an object (on infrared telescopes in space, etc.) as you'd want the reflective layer to be the outermost layer to prevent radiation from reaching a portion of the insulated object(in this case the substrate of the blanket) which could absorb such and pass heat through the metallized layer via conduction, but this mechanism doesn't seem relevant in this application, where heat is sought to be retained and conductive losses greatly surpass radiative losses in magnitude- esp since the metallized surface pointing in would if anything increase conduction to the blanket itself. Does this make sense to anyone? The only explanation I can see for a side-preference is: a) the metallic side facing inward would reduce environmental abrasion of the metallic coating, increasing durability. Hopefully someone can comment or explain any mistakes I've made. -- Δζ ( talk) 04:07, 21 December 2009 (UTC)
I think that the 'gold' surface on some sheets is there for search and rescue reasons, as gold against white snow is more visible than silver. However, the gold surface used as the user facing surface may also decrease infrared heat loss. What I don't understand, is why make a sheet with two different reflective surfaces, if a gold surface is better than silver ... one obvious reason, I guess, would be cost. —Preceding unsigned comment added by 90.28.148.47 ( talk) 09:55, 9 January 2010 (UTC)
The difference in reflection from those two different sides is negligible. Until someone can cite proper research, I'll simply delete the sentence claiming a difference between the two sides
91.47.181.31 (
talk)
23:06, 28 January 2010 (UTC)
Does anyone know if the Soviets copied the idea for use by their cosmonauts? I assume they are standard now on all space missions, now that the Cold War is over and they are commonly available in stores. GBC ( talk) 15:20, 22 February 2010 (UTC)
"Civilian versions may be ..."
'Civilian' as opposed to what? One would expect this to be used to differentiate from 'military', but that obviously isn't the case for NASA, and other space agencies. Nor would 'commercial' or 'professional' make any sense. I've replaced it with "They may be...".
107.77.75.18 ( talk) 04:23, 2 December 2014 (UTC)
I am a former spacecraft design engineer and the satellites I worked on all used what we called "thermal blankets," which is exactly what is described here. The article's Manufacturing section only hints at this usage, and needs to be expanded. In the meantime, I added this usage to the lede so I could link to this page from Black Knight satellite conspiracy theory which involves a lost in orbit thermal blanket. RobP ( talk) 23:57, 17 March 2017 (UTC)
Are there any independent scientific studies on these blankets? — Preceding unsigned comment added by 95.91.182.132 ( talk) 19:56, 8 July 2018 (UTC)
At the moment the article includes "...which reflects up to 97% of radiated heat...". I could not find that figure in any of the present references. I used WikiBlame to locate the edit where it was added, and found https://en.wikipedia.org/?title=Space_blanket&diff=next&oldid=228644241 .
The reference at that time which might have contained the info I think is " http://www.insul.net/testdata.html Reflective Insulation Test data" but at the moment gives "Sorry! That page doesn't seem to exist."
At this point in the History, the figure was changed from "about 80%" to "up to 97%". It might be worth chasing up where the 80% came from. I have done my own web searches to try to find heat reflection data, but not succeeded in finding a reliable source.
FrankSier ( talk) 20:55, 2 August 2020 (UTC)
This is the
talk page for discussing improvements to the
Space blanket article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find medical sources: Source guidelines · PubMed · Cochrane · DOAJ · Gale · OpenMD · ScienceDirect · Springer · Trip · Wiley · TWL |
![]() | This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
|
space blankets are also used by a lot of gardeners: they're put down as weed control layers (the plant you want have to grow gets planted through a little hole, insect control (many bugs instinctively go to the bottom of a leaf--if light is relecting up, they can't find the "bottom"), reflecting light in shadier areas, and it's bright and light enough to blow if you hang up strips of it to scare birds. This is common enough that you can often find space blankets sold at garden and farm stores.
These 'blankets' reflect most of your radiated heat. But most of your heat loss is not radiated - it is conducted. Most of that through your exposed extremities like hands and head. Look at extreme mountaineers - they lose fingers and toes to frostbite. Feet get the most conduction to the snow. I never heard of other bits getting frostbite, but that's not a mountaineering story you would bring up eh guys?
I keep reading about space blankets being clever technology, but no hiker I met had much faith in them. Most considered them worse than useless, because people got false feelings of security from their magic hi-tech shiny space blanket. I never heard anyone say "My space blanket was lovely and warm!". Maybe because they died of hypothermia before they could demand a refund.
I considered getting a workmate to take an infra-red photo of me with various amounts of clothing, with and without a space blanket. Apart from being a bit kinky, it is effing cold right now.
I looked around for an alternative guinea pig (not a real one), and noticed my lunch: a hot ooty roll in aluminium foil. Different kind of pig, dead and fried. :-) Space blankets are just very thin aluminium foil, with plastic backing.
I can state that it looked very 'dark' in radiated heat, not surprising as shiny aluminium is not very emissive. Unwrapped a bit, the contents were glowing. So thermal radiation was being reduced.
However, it felt hot to the touch, so conduction was not being reduced. Ten minutes and it had gone from piping hot to lukewarm.SpareHeadOne 23:09, 1 December 2010 (UTC)
I'd have thought this was common sense - I do not know of any source of cold weather clothing that bothers with radiated heat. Everything I have seen involves trapping layers of air next to the body. Nobody wears aluminium foil clothes to keep warm. Space blankets are just very thin aluminium film on a plastic sheet. You can easily prove how ineffective it is by wrapping yourself in foil (or plastic sheet) and going out in the cold. SpareHeadOne 23:09, 1 December 2010 (UTC)
If I say hydrogen burns with a hot flame, that would be acceptable and credible. If I say hydrogen burns at a particular temperature, then I need a source for that figure. If I say hydrogen makes things cold when it burns (contrary to common belief), then I need backup.
It is common knowledge that on Earth, heat loss by conduction and convection is far greater than radiation. The vacuum flask proves this all the time. The glass ones often have silvering to reflect radiated heat, but stainless steel ones don't take silvering like glass. A boiling hot cup of tea in a typical room goes 'cold' in about 10 to 20 minutes. In a vacuum flask, it is still piping hot 8 or 9 hours later.
Do you really need a scientific citation for that?
You might want one for figures on the actual percentages.
Quoting the article: http://en.wikipedia.org/wiki/Vacuum_flask "At the temperatures for which vacuum flasks are used (usually below the boiling point of water), and with the use of reflective coatings, there is little infrared (radiative) transfer"
Thermal radiation is proportional to the 4th power of the absolute temperature. So one can feel heat radiated from something as hot as an electric fire, or light bulb filament if a few inches away. I don't know anyone who can feels warmth radiating from a human. SpareHeadOne 23:09, 1 December 2010 (UTC)
I've seen many claims that space blankets reflect high percentages of body heat(i.e. 80%), but have not seen any scientific literature supporting this, and find it highly questionable if not unlikely. Outdoorvegan 02:41, 23 April 2006 (UTC)
It's interesting to see almost my exact thoughts on this subject. I am a scientist (and climber) and have been considering using a "space blanket" for an ultralight back-country marathon. However, I don't want to be the guinea pig. I suppose I could test the material by using it in my backyard first, but I thought of all things, there would likely be data available. Alas, I have yet to locate any. I imagine the US patent office probably has the original information but I have yet to search there. Count me in for another person looking for real data on the subject.
go to " http://www.mpioutdoors.com/get-tech.htm", It has great space blanket data! —The preceding unsigned comment was added by 24.126.131.48 ( talk) 20:13, 25 April 2007 (UTC).
Blizzard rescue blankets use Reflexcell(TM) ... see Thermal Performance & vs Alternatives, although this source might not be considered Secondary, It does gain good provenance from being a supplier to the UK Military. Exit2DOS2000• T• C• 03:33, 10 October 2008 (UTC) MPIOutdoors is now Grabber Outdoors. It should be noted that "Space Blanket" is a registered trademark of Grabber, Inc. and should be cited appropriately. —Preceding unsigned comment added by 69.129.122.250 ( talk) 15:00, 29 January 2010 (UTC)
FYI- Grabber, Inc. is the owner of "Space Blanket" trademark. Subsequently, this article is improperly cited. — Preceding unsigned comment added by 69.129.122.250 ( talk) 19:22, 7 June 2011 (UTC)
I don't understand the above-indicated contention in the article (marked citation needed currently). If the metalized surface reduces radiative heat loss by reflecting it, then what difference does it make which side is the outer side? The layer will reflect regardless, its not like it disappears if you put it on the outside instead of the inside. Does the article claim it somehow acts as a one way radiation reflector? I could understand its preferred placement on the side of incoming radiation when you wish to wish to use it to prevent radiative energy from raising the temp of an object (on infrared telescopes in space, etc.) as you'd want the reflective layer to be the outermost layer to prevent radiation from reaching a portion of the insulated object(in this case the substrate of the blanket) which could absorb such and pass heat through the metallized layer via conduction, but this mechanism doesn't seem relevant in this application, where heat is sought to be retained and conductive losses greatly surpass radiative losses in magnitude- esp since the metallized surface pointing in would if anything increase conduction to the blanket itself. Does this make sense to anyone? The only explanation I can see for a side-preference is: a) the metallic side facing inward would reduce environmental abrasion of the metallic coating, increasing durability. Hopefully someone can comment or explain any mistakes I've made. -- Δζ ( talk) 04:07, 21 December 2009 (UTC)
I think that the 'gold' surface on some sheets is there for search and rescue reasons, as gold against white snow is more visible than silver. However, the gold surface used as the user facing surface may also decrease infrared heat loss. What I don't understand, is why make a sheet with two different reflective surfaces, if a gold surface is better than silver ... one obvious reason, I guess, would be cost. —Preceding unsigned comment added by 90.28.148.47 ( talk) 09:55, 9 January 2010 (UTC)
The difference in reflection from those two different sides is negligible. Until someone can cite proper research, I'll simply delete the sentence claiming a difference between the two sides
91.47.181.31 (
talk)
23:06, 28 January 2010 (UTC)
Does anyone know if the Soviets copied the idea for use by their cosmonauts? I assume they are standard now on all space missions, now that the Cold War is over and they are commonly available in stores. GBC ( talk) 15:20, 22 February 2010 (UTC)
"Civilian versions may be ..."
'Civilian' as opposed to what? One would expect this to be used to differentiate from 'military', but that obviously isn't the case for NASA, and other space agencies. Nor would 'commercial' or 'professional' make any sense. I've replaced it with "They may be...".
107.77.75.18 ( talk) 04:23, 2 December 2014 (UTC)
I am a former spacecraft design engineer and the satellites I worked on all used what we called "thermal blankets," which is exactly what is described here. The article's Manufacturing section only hints at this usage, and needs to be expanded. In the meantime, I added this usage to the lede so I could link to this page from Black Knight satellite conspiracy theory which involves a lost in orbit thermal blanket. RobP ( talk) 23:57, 17 March 2017 (UTC)
Are there any independent scientific studies on these blankets? — Preceding unsigned comment added by 95.91.182.132 ( talk) 19:56, 8 July 2018 (UTC)
At the moment the article includes "...which reflects up to 97% of radiated heat...". I could not find that figure in any of the present references. I used WikiBlame to locate the edit where it was added, and found https://en.wikipedia.org/?title=Space_blanket&diff=next&oldid=228644241 .
The reference at that time which might have contained the info I think is " http://www.insul.net/testdata.html Reflective Insulation Test data" but at the moment gives "Sorry! That page doesn't seem to exist."
At this point in the History, the figure was changed from "about 80%" to "up to 97%". It might be worth chasing up where the 80% came from. I have done my own web searches to try to find heat reflection data, but not succeeded in finding a reliable source.
FrankSier ( talk) 20:55, 2 August 2020 (UTC)