Aerospace Engineers manufacture and design aircraft, satellites, missiles, aeronautical and astronautical products and technologies for development, research, defense, and commercial use. They document and evaluate the production of aircraft and aircraft technologies, including commercial and military airplanes, propulsion systems, navigation systems, instrumentation, communication, and thermodynamic and aerodynamic materials used in flight. Aerospace Engineers use highly complex computer systems and software to model, design, evaluate, and simulate parts, products, and vehicles in order to determine if proposals are financially feasible and whether designs will meet regulatory and safety standards. They confer with each other on large-scale projects that require group input, completing a multitude of tasks on a single project through the shared duties of many engineers.