Scientific progress often stems from the desire to explore the unknown. In astronomy and space science, the National Academies periodically produce "decadal surveys" to set priorities for disciplines or subfields. These surveys, however, typically require follow-up reports to translate broad recommendations into actionable plans. Dr. Karl Stapelfeldt and Dr. Eric Mamajek, the two chief scientists of NASA's Exoplanet Exploration Program (ExEP), have just published the program's "tactical" roadmap on arXiv. The document outlines 17 science objectives to be pursued over the next 3–5 years.

The plan centers on precursor science for the Habitable Worlds Observatory (HWO), the fusion of the former LUVOIR and HabEx concepts, whose flagship goal is to characterize 25 potentially habitable exoplanets. To achieve this, a foundational understanding of HWO mission requirements is essential, including estimating the occurrence rate of temperate rocky planets, determining the types of exoplanets detectable by different architectures, modeling exoplanet atmospheres, and understanding atomic spectral features.

Interpreting spectroscopic results and defining formation pathways for planets and their host stars are also key objectives. Whether revealing planetary physical parameters or determining host-star properties, knowing the targets before HWO begins observations is critical for correct data analysis. The report lists current mitigation strategies and provides links to various efforts aimed at closing knowledge gaps, such as the Exoplanet Opacity Database and the High-contrast Ground-based Imaging Data Challenge, offering multiple entry points for interested contributors.

Despite a 47% budget cut to the Astrophysics Division that may affect missions like HWO, the authors remain undeterred by NASA's recent workforce reduction plans. Amid budget and personnel changes, those passionate about the search for habitable worlds will continue to follow developments closely and use this roadmap as a guide for exploring potentially habitable planets.