Embedded Computing for Wavefront Control on Future Space Telescopes

Abstract

Future space telescopes will use adaptive optics to suppress starlight to directly image and characterize exoplanets. A measurement using this technique may be the first to detect extraterrestrial life in the universe. However, the real-time execution of adaptive optics control algorithms places unprecedented demands on spaceborne processors. Previous work has determined that processing limitations can degrade the achievable contrast and scientific yield of future exoplanet imaging missions. In this work, we quantify the relationship between adaptive optics processing needs and high contrast performance for the Habitable Worlds Observatory (HWO), a mission expected to launch in the 2040s and achieve the 10^-10 contrast necessary to image Earth-like planets around Sun-like stars.

We survey the current landscape of high-order wavefront sensing and control (HOWFSC) algorithms for a future mission like HWO. We parameterize the compute requirements of multiple algorithms through analyses of computational patterns, benchmarks, and problem scaling. In parallel, we assess the capabilities of current and emerging spaceborne processors. We integrate these findings to model processor requirements across several dimensions of telescope design, and we predict whether various processor choices can meet the computational demands of specific HWO configurations. To validate our models, we implement HOWFSC algorithms on representative embedded processors and compare measured performance to predictions. These implementations also reduce risk for spaceflight by increasing the technology readiness level (TRL) of the algorithm–processor pairing to TRL 4.

Given the significant uncertainty in HWO’s eventual design, we extend our deterministic models using Monte Carlo methods to evaluate system performance under uncertainty. We identify key sources of uncertainty and estimate the achievable contrast across a range of system configurations. Our results show that offloading computation to the ground is an important architectural option for most HWO designs. Even under optimistic assumptions, current space processors are insufficient to support the full range of HWO configurations. However, newly developed efficient algorithms substantially reduce the computational burden. Overall, we estimate that current technology has only a 40% probability of supporting HWO’s mission goals without additional architectural innovations. We conclude by recommending combinations of onboard computing, ground offloading, and optical design constraints to help close this technology gap as the mission design matures. In particular, we find that telescope stability and ground-in-the-loop performance are primary drivers of contrast performance, while algorithmic advances such as AD-EFC and onboard compute approaching ground-based GPU performance also provide significant benefits.