The Water Recovery X-Ray Rocket (WRXR) was a suborbital rocket payload that was launched and recovered in April 2018. The WRXR flew two technologies being developed for future large x-ray missions: x-ray reflection gratings and a hybrid CMOS detector (HCD). The large-format replicated gratings on the WRXR were measured in ground calibrations to have absolute single-order diffraction efficiency of ∼60  %  , ∼50  %  , and ∼35  %   at CVI, OVII, and OVIII emission energies, respectively. The HCD was operated with ∼6  e⁻ read noise and ∼88  eV energy resolution at 0.5 keV. The WRXR was also part of a two-payload campaign that successfully demonstrated NASA sounding rocket water recovery technology for science payloads.¹