3.1 Spaceframe & Structure
A broad, heavily-reinforced spaceframe with battle-section separation, built around the third (dorsal) nacelle assembly.
The Vanguard's spaceframe is broader and heavier than its siblings, built to carry the loads of a third nacelle, a deep magazine, and an armored hull. The command hull mounts over a broad engineering section that houses the high-output core and the dorsal nacelle assembly.
Reinforcement
The trititanium-laced frame is reinforced well beyond survey standard, with a structural-integrity-field grid rated to hold the hull together through sustained weapons fire and high-load combat maneuvering. Critical spaces — cores, magazines, antimatter pods — are individually compartmentalised and armored.
Battle-section separation
Like the Galaxy and Meridian, the Vanguard can separate its command hull from the battle section, but here the doctrine is tactical first: the battle section is a fully-capable warship in its own right, letting a commander commit the heavy section while evacuating non-combatants in the command hull.