Hubble's Imaging Spectrograph to get New Life

Hubble and Atlantis over northeastern Africa at 7:25 am

The fourth of five spacewalks to service the Hubble Space Telescope will focus on the repairs of its Imaging Spectrograph which failed in August 2004.

Today's spacewalk is scheduled to begin at 9:16 am EDT, and will be the 81st spacewalk from the space shuttle going back to 1983. Today's orbital walk should last 6 1/2 hours.

Of the Imaging Spectrograph on Hubble, according to Hubble Control in Greenbelt, Md., "its main function is spectroscopy - the separation of light into its component colors or wavelengths to reveal information about the chemical content, temperature and motion of planets, comets, stars, interstellar gas and galaxies".

Astronauts Mike Massimino and Mike Good will use diligence as they replace a low voltage power supply card. A failed power converter on the card is why the Imaging Spectograph went into a safe mode in 2004.

The duo will remove 111 screws on a plate cover to allow access to the spectrograph. They then will take the old card out and click into place the new power supply card. Then the two will use a new cover with two lock-down points which will close up the "cavity" as this replaces the one which took 111 screws to secure.

A very important piece of equipment, the Space Telescope Imaging Spectrograph or STIS, is not responsible for the beautiful Hubble images we see each week. Instead STIS measures the color and wavelengths of an astronomical object to receive a full understanding of its make up. As one Hubble scientist in Greenbelt put it, it "puts the “physics” in astrophysics".

Another task to be performed is the installation of a New Outer Blanket Layer on Bay 8 of the space telescope to provide better insulation to internal instruments. Hubble Control hopes that this weeks repairs will keep the telescope operation through 2014 as it scans the universe from an altitude of 565 km or about 350 miles above earth.

The seven member flight crew led by commander Scott Altman, awoke this morning at 4:31 am EDT, to the song New York State of Mind performed by Billy Joel, and played for Massimino. This will be Massimino and Good's second and final spacewalk of the mission. Thus far, Massimino has 22 hours & 42 minutes of spacewalking time.