This goes along perfectly with a robot costume, and was made in collaboration with this robot.
Credit to fungus amungus for the original idea. He claims to have created full-on shiny pants, a more difficult version of these leg coverings. I first attempted to make pants, but the upper part of the pants is very difficult without a pre-made pants stencil and these space pants tend to get very warm. So I opted to just make the legs, which are versatile enough by themselves plus much easier to make and cooler (in both senses!).
*Note: they only look like they belong in space. Don't actually use them in space.
Step 1: Materials
An emergency blanket. It's pretty standard as part of a first aid kit (though you'll want to replace it if you take it from one). It should be extremely shiny silver. It comes in a very small package but unfolds into a pretty expansive thin blanket.
Blue tape or other not-so-sticky tape for temporarily taping down the blanket.
Tape measure or equivalent measuring device.
Your leg. To use as a reference.
Sharpie or equivalent writing utensil.