Elon Musk: https://x.com/elonmusk/status/1796031244846645493

With extreme effort, Starship will eventually take reusability to ~100%. There are many tough issues to solve with this vehicle, but the biggest remaining problem is making a reusable orbital return heat shield, which has never been done before. The Shuttle’s heat shield required over 6 months of refurbishment by a large team, so was not reusable by any reasonable definition of the word.

This will take a few kicks at the can to solve and requires building an entirely new supply chain for low-cost, high-volume and yet high-reliability heat shield tiles, but it can be done.

Andy Lapsa: https://x.com/AndyLapsa/status/1796211187396612430

This is why we started from day 1 thinking hard about rapidly reusable heat shields. It’s metallic, ductile, and the surface temperature is tailorable and controllable well below material limits. It certainly hasn’t been to space (or back) yet, but to the best ability on earth we’ve tested it to the full heat load expected during reentry profiles.

For their upper stage, Stoke Space is planning to use an expander bleed cycle to actively cool the heat shield. It will be interesting to see how this approach compares to Starship’s passive ceramic tiles.