Hydrocode
A hydrocode is a computer program that simulates the shock waves, melting and flow of material during impacts.
A hydrocode is a type of computer model used to simulate extremely violent events, such as asteroid impacts, in which solid materials flow almost like fluids under enormous pressures. The program divides the impactor and target into many small cells and calculates how pressure, temperature, density and motion change in each over tiny time steps.
Hydrocodes are used to understand how craters form, how much rock is melted or vaporised, how fast fragments are ejected and whether rocks can be thrown off planets. Simulations helped show how Martian meteorites could be launched at escape speed without being completely melted, by spalling from near the surface where shock is weaker.
They are also used in planetary defence. Before and after NASA's DART mission struck Dimorphos in 2022, hydrocode models were used to predict and interpret the size of the crater and the amount of debris thrown off, which together determined how much the asteroid's orbit changed.
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