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This is a coordinated HST+XMM-Newton program to address the conditions that affect habitability on Earth-like planets around Sun-like stars. Both wavelength regimes openParfar-UV with HST comma X-rays with XMMclosePar are needed to constrain models sufficiently to represent realistic conditions. An approved TESS program for our targets will provide additional information on surface inhomogeneities openParspotsclosePar and their sizes and locations so that that can be taken into account as well. The FUV and X-ray fluxes from young stars are erosive of a planet.s atmosphere comma particularly for hydrogen comma but also for oxygen and nitrogen comma both chemically important elements.