In space you will need to use your body heat to produce the heat to be used to melt the plastic. The metal slab is what is making the heat that you are producing to melt it. You are in space and you will have trash pile up and you will need an object to reduce the space of what you are going to bring. The handle will have an insulator that will generate the heat and that you are going to melt the plastic to reuse it. You body is a heat source that conducts heat you are able to transfer the heat by putting your being on the handle and pressing down on the slab that will conduct heat. You are able to reuse the plastic by pressing down and rolling the plastic on an surface and rolling it into the size of the PLA that goes into the 3d printer.