Multi-Planet Hypersonic Shockwave & 1D Transient Heat Diffusion Engine
The entry simulator begins with a simplified exponential atmosphere. For Earth it uses sea level density one point two two five kilograms per cubic meter, and a scale height of eight point five kilometers. Start at one hundred twenty kilometers. The density is extremely small. Lower the chosen altitude toward twenty kilometers while holding the Earth profile fixed. The cyan point follows the exponential density formula. The common vertical axis is kilograms per cubic meter. Near twenty kilometers, the modeled density is about zero point one one six. This is a parameter comparison, not an integrated descent or a weather measurement. The source treats this scale height as constant. It does not resolve atmospheric layers, changing composition, or a measured local atmosphere. Convective heating in the source combines density, nose radius, and speed. Hold Earth density at fifty kilometers and the nose radius at zero point six meters. The horizontal axis uses u in kilometers per second. Inside the heat formula, v is one thousand times u in meters per second. Thus three kilometers per second means we cube three thousand meters per second. Begin at that input. The formula predicts about thirty five watts per square centimeter. Increase speed toward seven point eight kilometers per second. The yellow point rises along a cubic curve. The vertical axis uses watts per square centimeter, including the source conversion from watts per square meter. The ending value is about six hundred twenty four. This plot isolates the source convective term. It excludes the separate radiative expression, and does not claim a coupled trajectory or measured heat shield temperature. In the public simulation the thermal mesh also loses heat by surface radiation. Its material constants and failure thresholds are supplied assumptions. The source computes deceleration by dividing one half density times speed squared by ballistic coefficient. Hold Earth density at fifty kilometers and speed at seven point eight kilometers per second. Begin with coefficient one hundred kilograms per square meter. Increase ballistic coefficient toward eight hundred. The cyan point drops along an inverse curve on an axis labeled meters per second squared. The initial deceleration is about one thousand forty newtons per kilogram, and the final value about one hundred thirty. These are equivalent acceleration units. This comparison isolates drag at fixed speed and density. It is not the full path through the atmosphere. The source trajectory has fixed entry angle, a discrete time step, and a twenty node heat model. These teaching curves do not establish numerical convergence, thermal protection qualification, or actual vehicle safety.