My idea is a 3D printed Tourniquet. Tourniquets are used in the military to treat any deep cut or bullet hole. On the voyage to Mars or when astronauts actually arrive at Mars if there is a medical emergency such as a deep cut, astronauts will be able to resolve the situation and stop the injured person from bleeding out. The tourniquet is made out of ABS plastic. The plastic allows the device to be strong while still being light in weight. Its hollow design allows the plastic to be more flexible. It is also adjustable so it can be used in a variety of situations. Tourniquets are also very easy to use, there is hardly any training necessary to use one. If there is any risk of astronauts being cut deeply then I believe this very simple idea should be incorporated into the mission to mars. This simple device will be able to truly help in many medical situations and will also be able to save lives if needed.