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We propose to obtain a series of three early-time UV spectra of one stripped-envelope core-collapse supernova (either a normal SN Ib or a normal SN Ic) comma starting well before maximum brightness. The underlying nature of these objects comma from the mass-loss process stripping the envelope to the details of the explosion mechanism comma remain mysterious. Connections to gamma-ray bursts and X-ray flashes further motivate this study. Many high-redshift SNe are being found in deep transient surveys comma but the ability to distinguish between thermonuclear Type Ia SNe and stripped-envelope core-collapse SNe requires thorough knowledge of the latter at UV wavelengths with a low-z object. By comparing the evolution of the spectra as the photosphere recedes to deeper layers of the ejecta with our time series of spectral models comma we will gain a better understanding of the explosion mechanism and the degree of mixing during the explosion. Moreover comma we should be able to determine the metal content of the progenitor.s outer layers with our spectral models and compare with the measured metallicity of the environment. The heterogeneity seen in stripped-envelope SNe compels us to choose a normal SN Ib or SN Ic comma objects with DIFFERENT characteristics than the ones that HST has observed in previous Cycles (SNe Ic-pec comma IIb comma Ibn) comma thereby gaining further insights into this unique class of cosmic explosion. We need to seize this opportunity now comma while we have access to the space UV comma and indeed the UV is an HST Cycle 28 priority.