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The Space Telescope Imaging Spectrograph (STIS) was installed on the Hubble Space Telescope during Servicing Mission 2 in 1997. STIS stopped functioning in August 2004 due to a power supply failure, and is currently in safe mode pending a repair attempt during Servicing Mission 4. This will restore power to one of the two failed distribution channels.
The Fix
To repair STIS, astronauts will replace the low-voltage power supply board that contains the failed power converter. The fix is straightforward, but requires diligence as the instrument was not built with space surgery in mind. Engineers have, therefore, developed a number of special tools and devices to aid the astronauts and ensure no debris enters the instrument.
To begin the repair, astronauts will install a fastener capture plate over the top of the STIS electronics access panel. This plate must catch the 111 screw that will be removed in order to access the supply board, and any small fragments of metal that might escape as a screw is removed.
After detaching the panel (with the capture plate and fasteners attached), astronauts will remove the failed power supply card and click in the new one, much like replacing a circuit board on a computer.
A new, simplified panel is then installed over the open electronics cavity—only this time the 111 fasteners are not necessary. By throwing just two lever-like latches, the astronauts will lock the new panel securely into place.
Future Science
Working side by side, the COS-STIS tandem will offer a full set of spectroscopic tools for astronomers. A look at STIS’s scientific past offers a glimpse of future endeavours:
- Black Holes — looking for a gravitational Doppler shift in the light around supermassive black holes.
- Galaxies — STIS can simultaneously record the spectra of up to 50 spatially distinct locations within an extended object such as a galaxy.
- Stars — survey dust and gas ejected from unstable high-mass stars in the final stages of their evolution.
- Planets Around Other Stars — Analysing STIS spectra from transiting star-planet systems to determine atmospheric composition.
Links
Fact Sheet (PDF) |
