The ugly truth is that deep-space hardware wants to be a brick with pipes, not a knife with wings. Vacuum sets the rules. With no air, there is no lift, no drag, no reason to sculpt a fuselage for smooth flow; the only thing that matters is how much propellant you can push through a drive and how you keep the machinery from cooking itself.
What really dominates the silhouette is propulsion and power density. High-specific-impulse engines, from ion drives to nuclear thermal rockets, do not hide inside sleek fairings; they demand tanks for propellant, pressure vessels, turbopumps, power-conversion units and thrust structures that can transmit continuous acceleration without flex. Around that, engineers bolt on massive radiators because in vacuum the only way to shed waste energy is thermal radiation, governed by the Stefan–Boltzmann law, which punishes compact shapes and rewards broad, flat panels glowing faintly in infrared.
Even the crew volume becomes an afterthought. Radiation shielding, not cockpit aesthetics, sets its size and thickness, leading to stubby drums wrapped in water or polyethylene, tucked as close as possible to the propellant mass to exploit it as extra shielding. Aerodynamic forms would only add useless structural mass and surface area, hurting delta-v budgets derived from the rocket equation. So the honest drawing of a deep-space ship, once you stop pretending it must slice through air, is a flying engine block ringed with tanks and radiator wings, with a small, sheltered life-support bubble buried somewhere inside.
