Far Ultraviolet Spectroscopic Explorer (FUSE) satellite
was launched on June 14 1999 as part of NASA’s
“Origins” program. This satellite takes far ultraviolet spectra at 20
km/s resolution, with a sensitivity much higher than any previous instrument. This
has played an essential part in the examination of the Interstellar
was designed to gather the spectrum of stars and galaxies at a high
signal to noise ratio that the absorption of certain photons by
ions could be detected.
Information collected with the FUSE satellite was the primary source of
data for this analysis. However, a few spectra of certain wavelengths
were outside the range of FUSE, so data from the High Resolution
Spectrograph (HRS) and Space Telescope Imaging Spectrograph (STIS) were
used (instruments on the Hubble Space Telescope).