Ablative shield
Non-ablative shield
This 2D companion strips the heat-shield comparison down to the underlying thermal physics: drag the entry-velocity slider and watch the Sutton-Graves-style heat flux (roughly proportional to velocity cubed) drive two independent surface energy balances side by side. The reusable ceramic shield has no way to shed mass, so its temperature climbs the Stefan-Boltzmann curve toward an equilibrium where radiated heat matches incoming flux — an equilibrium that keeps rising with velocity until no ceramic can survive it. The ablative shield follows the same curve only up to its char temperature; above that, excess heat chars and vaporizes material instead of raising temperature further, which is why its live thickness readout recedes over time while its surface stays roughly capped. Live charts track both temperature histories and the ablative shield's remaining thickness so the trade-off — bounded, reusable temperature rise vs. sacrificial mass loss that stays within its thermal limit — is visible in real time.