2.1	STIS Repair and Return to Operations

The Space Telescope Imaging Spectrograph (STIS) had ceased science operations on 2004-Aug-03, due to the failure of a power supply within the Side-2 electronics, which had powered the instrument since May 2001, when a short circuit had blown a fuse, knocking out the Side-1 electronics.

In May 2009, during the fourth spacewalk of the HST Servicing Mission 4, (SM4), the STIS Side-2 circuit board containing the failed low voltage power supply was replaced. This repair fully restored the STIS instrument to operation with capabilities similar to those it had before the Side-2 failure. In the appropriate sections of this handbook, the performance changes since 2004 in detector dark currents, throughputs, and charge transfer efficiency (CTE) will be discussed.

Most figures and tables had been updated for the Cycle 17 version of this handbook, using our best estimates of instrument performance for Cycle 17. Except where otherwise noted, we have not revised these figures and tables to take into account the modest changes expected between those projected values and the estimated Cycle 21 performance. For more up-to-date performance estimates, users should consult the STIS ETCs available at:

http://www.stsci.edu/hst/stis/software/planning/etc/.

The sensitivities and other instrument parameters adopted for use with the Cycle 21 ETCs have been updated with our best estimates for April 2014.

STIS will be among the instruments available for inclusion in Cycle 21 Phase I proposals. Please consult the Cycle 21 Call for Proposals and the Cycle 21 Proposal Announcement Web pages, available through the Proposing Overview Web page at:

http://www.stsci.edu/hst/proposing/docs/proposingOverview

for any updates on instrument status.