The helmet was the most difficult part in making this costume come to life. I was set on having it glow blue inside, and making it ourselves. It took almost two weeks to paper mache these each night in order to create a thick enough layer that would hold its shape. (Blow a balloon up larger than your head, and then paper mache over it, once complete, pop the balloon inside.) We sanded them to make them smooth, spray painted them white and added clear eye shields bought from Home Depot.
Inside we taped some blue LED lights that would even blink if you wanted them to. For our oxygen tanks, we used Poland spring gallon water bottles and tops used for suction canisters that could only be found inside a hospital. Underneath the oxygen tanks we each had headlamps glued that illuminated the ground behind us as we walked.
The suit was fairly easy, we each had our own white outfits, and used colored electrical tape and NASA patches bought from the intrepid museum in Manhattan. These outfits were a HUGE hit. We could barely walk down the sidewalk without being stopped, and everyone wanted to try on our helmets.
This. Is. Awesome.