re guns for space in reference to the limits of acceleration with guns launching solid rockets as payloads thiokol provided me with samples and data on a reinforcement to solid motor grains for high accelerations solid motor propellants usually have a substantial percentage of aluminum in the mix for example the space shuttle srbs are percent aluminum the technique is to use a foamed aluminum structure the structure looks like the inverse of a set of bubbles an i suspect some bubbling process is used to form it in other words if you made a bunch of bubbles in molten aluminum then froze it this is what you get it forms a strong network of effectively aluminum wires in all directions the remaining solid fuel mix is infiltrated into the voids and you get aluminum reinforced solid propellant the foamed aluminum makes up about percent of the total propellant so there is still aluminum particles in the bulk grain the major improvement is the higher resistance to grain cracking which is the principal failure mode for solid propellant dani eder dani eder meridian investment company w h rt box athens al location deg n deg w m alt
