Disturbance reduction requirements for LISA

An overview is given of the sources and magnitudes of acceleration disturbances to the LISA proof masses (PMs). They are classified according to their sources as environmental noise, PM position sensor back-action, control-loop noise and PM-spacecraft (SC) stiffness. A general control model is used to establish relations among the noise sources, sensor errors and control-loop elements. Quantitative estimates are derived for the noise sources, and minimum requirements are inferred for sensor resolution and SC drag-free control-loop gain that are consistent both with the baseline in-band LISA budget for total acceleration noise and a possible extension to lower frequencies. For brevity, explicit expressions for each noise source are provided in tables, together with quantitative estimates for indicated parameter values. Additional tables list assumed parameter definitions and values; acceleration–noise goals and estimated totals; and minimum requirements for sensor resolution and SC control-loop gain, for frequencies ranging from 3 mHz down to 5 × 10−6 Hz.