The Space Telescope Imaging Spectrograph (STIS) was installed during Servicing Mission 2 in 1997, replacing the Goddard High Resolution Spectrograph (GHRS). STIS is a versatile instrument with a wide range of capabilities. Two unique capabilities provided by STIS include: long-slit spectrocopy (at two resolving powers) covering the ultraviolet through the visible, and ; a high resolution (R>100,000) echelle spectroscopy mode in the ultraviolet.

In August 2004, the HST STIS ceased operation, due to a failure in the Side 2 Low Voltage Power Supply (LVPS2). The LVPS2 provided power to the entire instrument, including all detectors and mechanisms. The Side 1 electronics had failed previously and are not usable. The portion of LVPS2 that failed is required for movement of the STIS mechanisms; the mechanisms are required to unshutter the instrument and to configure it for scientific observations. Hence the Side 2 failure left the instrument shuttered and in safe mode after 7.5 years of science operations. In the observing cycle prior to the failure, STIS accounted for fully 30% of allocated observing time for Hubble.

On May 17, 2009, during the fourth EVA of the SM4 mission, astronauts were able to affect repairs to the STIS. It passed aliveness and functional tests almost immediately. The final determination of the success of the repair will be announced sometime after Labor Day.