Stoke's Nova: stainless steel structure and a hydrogen-cooled metal heat shield
Published
What Stoke Space says: its first vehicle and the larger Nova Block 2 both use stainless steel skin-and-stringer construction, which it says needs almost no fixed tooling. The reusable upper stage re-enters behind an actively cooled metallic base heat shield with liquid hydrogen flowing through it, which Stoke's article contrasts with passive ceramic tiles. Block 2 is quoted at 15 t to low Earth orbit in a fully reusable configuration, and the page says Nova can deliver more than 4 t to GTO (it names no block and no reuse mode). Pathfinder flies seven Zenith engines; its first flight is planned for the first part of 2027 and Block 2's for 2029. Why it matters for materials: a cooled metal shield replaces a ceramic insulator with plumbing, so the open question is how the metal and its cooling passages survive repeated re-entry heating, thermal stress and fatigue. Our take: this is an architecture announcement from the company. No alloy grade, temperatures or reuse life are given, the heat-shield metal is not named, and the comparison with tiles is one-sided and unsourced. Almost no fixed tooling and all flight dates are company claims or targets. For context, our type 301 stainless page (Stoke names no stainless grade) lists a thermal conductivity of 16.3 W/m-K at 20 to 100 °C (annealed, ATI), while our CuCrZr page lists about 320 W/m-K for a copper alloy at 20 °C (Luvata). We are not saying which metal Stoke uses, because it does not say. What we would watch: the named shield alloy, coolant flow and any flown data. What would worry you most in a cooled shield?