Habitable Worlds Observatory needs picometer stability to observe Earth-like worlds

A new pre-print from the HWO Technology Maturation Project Office says the Habitable Worlds Observatory has advanced from Concept Maturity Level 2 to 3 and highlights that components will need stability at the picometer scale—about 1,000 times better than James Webb—to directly image Earth-like planets.

The Habitable Worlds Observatory (HWO) is a proposed NASA flagship telescope intended to search for signs of life on Earth-like planets and study ocean worlds, asteroids, galaxies and related processes. A new pre-print from the HWO Technology Maturation Project Office reports the mission concept has moved from Concept Maturity Level (CML) 2 to CML 3, entering a trade-space study phase. The report outlines the technical areas that must mature, including coronagraphs, large mirror stability, coatings and low-noise detectors. It emphasizes that components will need stability at the picometer scale to directly observe planets that are billions of times fainter than their host stars. Key details: - The HWO mission goal includes searching for signs of life on at least 25 Earth-like worlds, alongside studies of ocean worlds, hazardous asteroids, galaxy mapping and black hole–driven star formation. - To image Earth-like planets directly, elements of the observatory must not move or distort by more than a few picometers; a typical atom is about 100 picometers across and target planets can be ~10 billion times dimmer than their stars. - The James Webb Space Telescope has stability on the order of nanometers; HWO’s requirement is roughly 1,000 times finer. - The project uses Concept Maturity Levels to track progress; the paper announces advancement from CML 2 (initial feasibility) to CML 3 (trade space), where multiple configurations are modeled. - The trade-space work highlights two main launch-compatible aperture options under consideration: a 6.5–7 m non-folding aperture and an 8–8.5 m folded-segment design, plus development needs for deformable coronagraphs, advanced mirror materials, far-UV coatings and single-photon detectors. - The team plans detailed modeling over the next two years, aims for a Mission Concept Review around 2029 to move to CML 5, and notes that scheduling could be affected by NASA funding uncertainty. Summary: The paper frames HWO’s technical challenge as unusually exacting because of the picometer-scale stability required to image very faint, Earth-like planets. Over the next two years the project will model trade-offs between alternative designs and technologies, with a Mission Concept Review expected around 2029 and a goal of remaining on track for a launch in the early 2040s, though the official schedule will be set at the review and could be affected by funding uncertainties.