Has your space blanket also been on countless adventures but never left its ziplock bag? Let’s unpack that shiny piece of plastic and see what they’re actually made of.


Space and hiking have a lot in common. They both require you to drink through a tube, there’s a high barrier to going to the bathroom, and chances are you’ll see a shooting star. 

They also both require you to carry a shiny wad of plastic in the bottom of your first aid kit or daypack in case of emergency — I’m guessing astronauts have daypacks but haven’t been able to confirm this.


There are as many mysteries and oddities in a hiking pack as there are in space and number one for me has always been the space blanket. 

Why’s it called that? What’s it made of? And when can (or should) I actually use it?


What Actually Is A Space Blanket?

We’re about to uncover a mystery of cosmic proportions folks! @NASA’s James Webb Space Telescope/Flickr

Why is it called a space blanket?

Space blankets are also called solar blankets, mylar blankets, survival blankets or emergency blankets. 

They were originally adopted by NASA in 1973 as a makeshift sun or heat shield, after a spacecraft’s actual heat shield had broken. 

According to Mike Weiss of NASA, ‘Space blankets are to spacecraft as clothes are to people.’

What are space blankets made of?

According to NASA, ‘the material is created by depositing vaporized aluminium onto thin plastic substrates.’  

If you want the less-spacey explanation, they’re mostly made of a super thin, really strong plastic and this is coated in a layer of aluminium that is thinner than a single human hair. 

The end result is a shiny reflective sheet that can be folded down to about the size of a handkerchief.


When should you use it?

While most people have probably lugged* one on an overnight hike at some point, the majority (hopefully) wouldn’t have needed to unfurl it in the field. *Lugged, is also probably an unfair word to use, considering they only weigh about 50 grams or so. 

So, gram for gram, they’re one of the most useful tools in your first aid or survival kit.

Space blankets are ‘a passive warming system’, they won’t offer you insulation, but they will assist you in conserving your own body heat. 

These blankets will stop convective heat loss (from cold winds) and slow evaporative heat loss (from sweat) by increasing the humidity of the air close to your skin. 

Most notably, it will also prevent the loss of body heat from radiation, by simply reflecting it straight back at you, the wearer.

An often-cited statistic is that they’ll reflect up to 80% of your body heat.


Outdoor brands like Columbia are even incorporating space blankety features into their products. Their Omni-heat jackets are lined with thousands of tiny silver or gold dots and they’re seriously toasty!

Any other uses for the space blanket?

As mentioned, space blankets offer absolutely no insulation, so they have to be used and worn strategically; 

  • Wrap it around the outside of an insulating blanket
  • Use it as a weatherproof shelter
  • Use it as a ground sheet (combine with insulation)
  • Use it to signal for help (shiny and reflective)


Other Hot Tips

The space blanket requires radiant heat in order to reflect back to the wearer — that is to say, it’s not a source of heat in itself.

Therefore, if someone is hypothermic, their body won’t be producing enough heat to capture and you’ll have to introduce another source of heat like a hot water bottle to help warm them within the blanket.


What Actually Is A Space Blanket?

If you only take one thing away from this article. Let it be that these are not normal blankets… @JCHaywire/Flickr