Internal systems simulation

Project Apollo - NASSP simulates internal system states using a modified version of Radu Poenaru's System & Panel SDK (SPSDK).

Principals of Operation

SPSDK simulates and manages the internal state of a wide variety of system types by means of a set of three fundamental, separate but interrelated, simulation engines: thermal, hydraulic, and electrical. The states themselves are computed using a simple but computationally inexpensive Linear multistep method known as Eüler's Method. Propagation is accomplished by applying Eüler's method to solve an initial value problem, consisting of a known initial state (at the beginning of the current timestep), and a time-derivative, which is fundamental to the mechanics of the system type. Timesteps are typically broken down into multiple sub steps to avoid the numerical instability inherent to stiff numerical systems.