Sunday, May 17, 2009

The Agony and the Ecstacy of Space Walking

Today, our astronauts on the space shuttle proved their worth yet again by successfully repairing the Space Telescope Imaging Spectrograph, or STIS, during a long, frustrating, and ultimtely rewarding spacewalk. During the eight-hour marathon, astronauts Mike Massimino and Mike Good had to physically rip a handrail off of Hubble to get at the instrument, had to remove 111 screws that were designed to never need to be removed, had to deal with baulky tools, and had to go into the sensitive electronics of an instrument and replace the computer cards that send electricity to the instrument.

I watched parts of the spacewalk on NASA TV, and the astronauts were clearly frustrated and stressed. Yet they didn't lose their temper, and they didn't say any foul language (I think the worst I heard was something like, "This is so screwed up." I shocked at how mild that was compared to what I would have said, and I pride myself in keeping my language clean!)

The spacewalk ran hours over, one major job of installing new insulation didn't get done, and some of today's work was done yesterday. But the work they did was something that was never intended to be done to the Hubble, and it worked. The camera turned on after the repair, and quick checkouts said everything was alive.

During later checkout of the instrument, the spectrograph shut down due to a low temperature reading. I think there's a good chance that everything will work out okay once the spectrograph warms up. Just amazing work by the entire shuttle crew!

The STIS is an optical spectrograph; it splits light up into its component colors, which allows for detailed chemical analysis of stars and galaxies. STIS suffered an electronics failure in 2004, and has been sitting idle ever since. When it was working, STIS took the first spectra of planets around other stars, detected black holes in the centers of dozens of galaxies, and allowed all sorts of detailed work on lots of astronomical objects.

Many of my colleagues will be very happy to have STIS working again. Although spectroscopy doesn't produce very pretty pictures, it often reveals much more information than our pictures can. Because of that, spectrographs are often the unsung heroes of telescopes. Both COS and STIS will be used just as much as the new and refurbished imaging cameras on Hubble, but you won't see nearly as many pictures in press releases about these discoveries.

Tomorrow will probably be the Hubble mission's last spacewalk. Astronauts Grunsfeld and Feustel will replace Hubble's other battery pack, replace one of the fine guidance sensors, and then will do as much insulation repair as time allows.

1 comment:

  1. This article has been added to the Astronomy Link List.

    ReplyDelete