> Why not use an elongated blimp shape? Why the v? For the upper stage: it would only be an airship at the start, then transition into an inflatable hypersonic

> Why not use an elongated blimp shape? Why the v? For the upper stage: it would only be an airship at the start, then transition into an inflatable hypersonic lifting body before eventually reaching orbital velocity. Very similar to how a seaplane starts swimming by displacement, then transition to gliding on the water before eventually taking off. For the lower stage: I suspect the shape is more like a branding thing, and knowledge transfer ("perhaps some of what we would have to learn about v-shaped blimps can be learned in the lower atmosphere?")