End-to-end simulations for the LISA Technology Package

We present an end-to-end simulation facility which has been developed in the framework of the LISA Technology Package (LTP) architect study for SMART-2, the technology demonstration mission that precedes LISA. The simulator evolves positions and orientations of the spacecraft and two test masses contained in the inertial sensors of LTP under the influence of external and internal forces and torques and under the influence of control loops for satellite drag-free control (DFC) and electrostatic test mass suspension. Altogether, a coupled system with 18 degrees of freedom is solved numerically. A series of test runs has been performed to verify the correct functioning of the various models contained in the end-to-end simulator and to provide a preliminary assessment of the performance of DFC algorithms and control laws for test mass suspension, which are currently foreseen for use in the basic operation mode of LTP.