  We obtained UV spectra of X-ray binary Scorpius X-1 in the 900-1200 A range
with the Far Ultraviolet Spectroscopic Explorer over the full 0.79 day binary
orbit. The strongest emission lines are the doublet of O VI at 1032,1038 A and
the C III complex at 1175 A. The spectrum is affected by a multitude of narrow
interstellar absorption lines, both atomic and molecular. Examination of line
variability and Doppler tomograms suggests emission from both the neighborhood
of the donor star and the accretion disk. Models of turbulence and Doppler
broadened Keplerian disk lines Doppler shifted with the orbit of the neutron
star added to narrow Gaussian emission lines with undetermined Doppler shift
fit the data with consistent values of disk radius, inclination, and radial
line brightness profile. The Doppler shift of the narrow component with the
orbit suggests an association with the donor star. We test our line models with
previously analyzed near UV spectra obtained with the Hubble Space Telescope
Goddard High Resolution Spectrograph and archival spectra obtained with the HST
Cosmic Origins Spectrograph.
