Future planned space telescopes, such as the IR/O/UV Large Telescope, recommended by Astro2020 will be used to directly image exo-Earths. They will employ high-order wavefront sensing and control (HOWFSC) to correct static and slow wavefront errors in the image plane to achieve contrasts better than 10 9 . Our work evaluates the computational requirements for HOWFSC algorithms and compares these to the capabilities of processors that are expected to be available during mission development. We find that HOWFSC creates unprecedented requirements for space-based computational power, such as the ∼10 13 floating-point operations necessary to generate the dark hole, based on the Large UV/Optical/IR (LUVOIR) study. In our worst-case estimates, maintaining an LUVOIR-size dark hole at 10 10 contrast might require up to several orders of magnitude more computational throughput than available on the most advanced radiation-hardened processor.

Future planned space telescopes such as HabEx and LUVOIR will be used to directly image exo-Earths. These telescopes use coronagraph instruments to suppress starlight and resolve dim exoplanets. They will employ high order wavefront sensing and control (HOWFSC) to correct static and slow wavefront errors in the image plane to achieve contrasts above 10 9 . This work evaluates architectures to meet the computational requirements for HOWFSC algorithms with available processors.We find that the computational requirements of HOWFSC will impose unprecedented requirements on space-based components and that typical combinations of computational resource and control architecture will consume significant observation time. Science yield from the space telescope can be improved, and mission risk and cost reduced, by using co-flying or ground-in-the loop computational offload architectures.In particular, a high-capability co-flying processor could use commercial components 10 4 times more powerful than typical radiation hardened options. This would enable key HOWFSC algorithms to run in seconds rather than hours or days, removing operational constraints on the science mission. While commercial processors may be more susceptible to total ionizing dose radiation effects over the expected mission lifetime of 5-10 years, the relatively low cost of development and replacement launches make these co-flying processors an attractive option.We evaluate three major co-flying architecture trades: (i) inter-spacecraft distance, (ii) risk classification, and (iii) processor selection. We find that one or more low-cost replaceable co-flying processors with COTS components and flying several kilometers from the telescope spacecraft can provide all needed computation.

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