LUVOIR-ECLIPS closed-loop adaptive optics performance and contrast predictions

Abstract

One of the primary science goals of the Large UV/Optical/Infrared Surveyor (LUVOIR) mission concept is to detect and characterize Earth-like exoplanets around nearby stars with direct imaging. The success of its integrated instrument ECLIPS (Extreme Coronagraph for Living Planetary Systems) depends on the ability to stabilize the wavefront from a large segmented mirror at a level of a few picometers during an exposure time of a few hours. To relax the constraints on the mechanical stability, ECLIPS will be equipped with a wavefront sensing and control (WS&C) architecture to correct wavefront errors at high temporal frequencies (<~1 Hz). These errors are expected to be dominated by spacecraft structural dynamics exciting vibrations at the segmented primary mirror. In this work, we present detailed simulations of the WS&C system within the ECLIPS instrument and the resulting contrast performance. This study assumes realistic wavefront aberrations based on a Finite Element Model of the telescope and the spacecraft structural dynamics. Wavefront residuals are then computed according to a model of the adaptive optics system that includes numerical propagation to simulate realistic images on the wavefront sensor and an analytical model of the temporal performance. An end-to-end numerical propagation model of ECLIPS is then used to estimate the residual starlight intensity distribution on the science detector. We show that the contrast performance depends strongly on the target star magnitude and advocate for the use of laser metrology to mitigate high temporal frequency wavefront errors and increase the mission yield.