Exploring Space Weather From Young Solar-like Stars as Windows to Exoplanetary Habitability

Young solar-like stars are efficient generators of magnetic activity, superflares, coronal mass ejections (CMEs), and stellar energetic particles. These phenomena drive the early evolution of stars and shape the habitability of exoplanets. The Hubble Space Telescope (HST), with its unmatched far-ultraviolet (FUV) and near-ultraviolet (NUV) sensitivity, provides a uniquely powerful window into these processes one that no current or near future facility can replicate. This white paper articulates four interconnected science questions that require Hubble continued operation and targeted observing programs over the next 10 to 15 years, enriched by new multi-wavelength insights from deep X-ray surveys of open clusters. We describe required instrument capabilities, critical synergies with contemporaneous missions (JWST, Chandra, XMM Newton, TESS, and the Nancy Grace Roman Space Telescope), and the fundamental role Hubble observations will play in calibrating and informing the design of the Habitable Worlds Observatory (HWO). We advocate for large scale coordinated campaigns targeting young solar-like stars as the highest priority science program for the coming decade.