For some time, I have been thinking on how to make the ultimate rocket cryogenic propellant compatible. I thought of a geometric layout which is also applicable to my HTP + LPG variant of the rocket. The LOX tanks would be placed around an outer ring. The fuel tanks (LPG or LNG) will be placed inside this outer ring. The tanks are arranged such that each outer oxidizer tank has four contact points: two with the adjacent oxidizer tanks and two with the fuel tanks behind them. The fuel tanks also have four contact points: two with the adjacent fuel tanks and two with the oxidizer tanks in front of them. This forms a highly rigid structure with minimal dead weight.
Having multiple smaller tanks allows for thinner tank walls compared to a single larger tank of the same total volume. The major advantage of this layout compared to my previous design is that adjacent tanks in each ring are of the same propellant type. This allows a circular, toroidal manifold to connect each tank of the same type. These dual concentric manifolds are highly rigid due to their toroidal geometry, acting as structural hoop frames that resist internal pressure and buckling forces far better than classical rocket piping networks. As a result, there is no need to vary tank diameters to balance propellant consumption, and fluid pressure self-equalizes symmetrically. Unlike the outer tanks, the inner tanks can have a lower height while remaining aerodynamically shielded from the ambient airflow.
Similar to the non-cryogenic propellant design, the engines are positioned directly in the intermediate annular zone between the two circular manifolds. Specifically, each engine is placed precisely at the intersection points of the LOX and LNG tank contacts. The structural studs connecting adjacent tanks are integrated at these identical nodes to support and transfer the engine thrust upward to the upper stages of the rocket. By nesting the engines and studs directly at these intersection junctions, the massive axial forces align perfectly with the load-bearing space frame, eliminating crossing fluid lines and bypassing the thin tank walls entirely.
Unlike my HTP + LPG rocket design, we cannot use altitude-compensating aerospike nozzles, as they would melt under the immense thermal loads of the LOX + LNG exhaust. However, this design allows for an exceptionally high engine count to generate the total thrust, and not all of them need to be fired throughout the entire flight. Therefore, the first-stage engines can utilize conventional bell nozzles optimized for specific altitude steps, sequentially staging or shutting down to minimize over-expansion and under-expansion losses across the trajectory. The second and third stages operate exclusively in a vacuum, so all of their nozzles will be vacuum-optimized.
This concentric ring tank placement, coupled with unified manifolds, allows the upper stages to feature fewer engines than the total tank count, reducing the dead weight of the critical upper stages. An important characteristic of this design is that it keeps individual tanks compact while allowing the overall architecture to be exponentially scaled. To create super-heavy or ultra-heavy payload classes that dwarf vehicles like Starship and the Saturn V, the ring can be expanded simply by adding more standardized tank segments circumferentially, or by stacking additional concentric rings outward. Because individual tank dimensions are restricted to standard shipping container constraints, the manufacturing tooling remains identical regardless of the rocket's ultimate diameter. The vehicle can be manufactured anywhere in the world using existing intermodal freight networks and rapidly assembled at the launch site.
In order to simplify the structural design and reduce dead weight, I propose that the upper stages maintain the same outer ring diameter so that the load-bearing supporting studs can traverse upward in a straight line. As a result, if the first-stage tank height matches a full container length, the second stage would be shorter, and the third stage shorter still. This enables straightforward logistics, and the total height of the rocket remains highly compact. Additionally, if the launch tower is designed to be modular with a fixed maximum height, varying rocket geometries (where only the outer diameter changes based on the number of tank segments used) can be serviced by the same tower setup, requiring fewer active sections for smaller rocket variants. Multiple smaller tanks also allow for much faster and safer simultaneous fueling operations through the unified toroidal manifold architecture.
Finally, the void space enclosed between stage two and stage three is utilized as a unified payload bay. This allows payloads to be integrated and stored in their fully extended configurations, negating the need for complex deployment or folding mechanisms. This design choice makes the payload structurally stronger, lighter, and more reliable.
No comments :
Post a Comment