Yesterday's Starship landing saw at least one Raptor burning copper. Given that copper oxidizes with oxygen at the temperatures and pressures found in a Raptor combustion chamber, what properties does it impart on the combustion?
What would be the exhaust velocity of a hypothetical tri-propellant methane-copper-oxygen engine? Would that translate to specific impulse in the same fashion as conventional (OK, methane isn't yet conventional) rocket fuels do? I'm assuming a molecular weight higher that hydrogen so less Isp of course, but how would it compare to e.g. RP-1? Would gaseous copper (gaseous in the chamber after oxidizing, but no reason that the stored fuel could not be solid) have a higher or lower molecular weight than hydrocarbons such as RP-1?