FUSE carried four 0.35m far ultraviolet telescopes each with an ultraviolet high resolution spectrograph. The detectors cover the far ultraviolet band from the hydrogen ionization edge at 912 Angstroms to 1187 Angstroms, just short of the Lyman alpha line at 1215 Angstroms. These far UV spectra were to be used to measure the abundance of deuterium in the universe, as well as study helium absorption in the intergalactic medium, hot gas in the galactic halo, and cold gas in molecular clouds from molecular hydrogen lines.

Typical orbit: 761 km circular orbit, 25 deg inclination.

• 1999 June 24 - FUSE - Launch Site: Cape Canaveral. Launch Complex: LC17A. Launch Vehicle: Delta. Perigee: 753 km (467 mi). Apogee: 769 km (477 mi). Inclination: 25.00 deg.
  The Delta 3-m payload fairing was successfully jettisoned and the Far Ultraviolet Spectroscopic Explorer was placed in a 754 km x 769 km x 25.0 degree initial orbit. After separation the Delta second stage then a depletion burn and was left in a 182 x 915 km x 19.1 degree orbit from which it would quickly decay out of orbit. Checkout of FUSE in orbit was proceeding well as of July 1.