![Mapping of the science cases proposed by the Science Working Groups (center) to the questions and discovery areas identified by Astro2020 (left and right). The transparencies of the lines indicate the number of connections with darker lines indicating stronger links between the SWG and the Astro2020 topic. -- [astro-ph.IM]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Early-Exploration.png?fit=1200%2C667&ssl=1)
[astro-ph.IM] The Habitable Worlds Observatory (HWO) is a future NASA flagship mission concept identified by the Astro2020 Decadal Survey as the highest priority for large space missions.
HWO should conduct “transformative astrophysics” and search for biosignatures in the atmospheres of approximately 25 potentially Earth-like planets. To further the early-stage development of HWO, NASA formed the Science, Technology, Architecture Review Team (START). In turn, START invited the scientific community to join working groups to explore the potential discovery space.
In this paper, we present 70 science cases that resulted from this process. The cases address four scientific pillars: growth of galaxies (15 cases), evolution of the elements (13 cases), solar systems in context (32 cases), and living worlds (10 cases). Combined, they would address 27 of the 30 science questions and discovery areas identified by Astro2020.
The 140 observing programs needed for the 70 investigations encompass a rich variety of spectroscopic (for 87% of science cases) and photometric (for 30%) observations extending from the UV to the NIR. Additionally, high-contrast and polarimetric capabilities would be needed for 34% and 27% of science cases, respectively.
Access to UV wavelengths is critical: 83% of science cases need data at wavelengths <400 nm, and 26% extend to <100 nm. In the NIR, 26% of science cases need observations at wavelengths >=2000 nm. Pursuing the full portfolio of science would also necessitate precise astrometry for planet mass measurement, rapid response capabilities, a large instantaneous field of regard, non-sidereal tracking, saturation mitigation strategies, and high dynamic range.
Comments: 215 pages, 18 figures, 16 tables. This to-be-submitted manuscript summarizes and synthesizes science cases developed by the Habitable Worlds Observatory START and science working groups. See Table 1 for a roadmap, Table 5 for a list of science cases, Figure 11 for a visualization of common observational needs, Figure 16 for connections to Astro2020, and Tables 6-15 (after conclusions) for details
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2608.11294 [astro-ph.IM] (or arXiv:2608.11294v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2608.11294
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Submission history
From: Courtney Dressing
[v1] Tue, 11 Aug 2026 17:36:36 UTC (4,095 KB)
https://arxiv.org/abs/2608.11294
Astrobiology, Astronomy, exoplanet,
