Orbital mechanics and mission architecture
Trajectory design works with gravitational dynamics, orbital energy, inclination, transfer windows and maneuver budgets. Designers trade travel duration against propellant demand, launch mass, spacecraft performance and reliability. Planetary missions may exploit gravity assists; crewed systems add complex life-support and abort considerations.
NASA’s Moon to Mars Architecture illustrates the systems perspective: exploration objectives are translated into transport, surface operations, data, power, habitation and logistics capabilities that can be tested incrementally.

