Mission Control Center Status Report # 12

Saturday, December 25, 1999 – 10 a.m. CST

Christmas Day onboard the Shuttle Discovery began with seasons greetings for Commander Curt Brown, as
the crew awoke to Bing Crosby’s “I’ll Be Home for Christmas.”

“Merry Christmas to all of you down there,” replied Brown. “And Hubble will be home for Christmas ’cause
today we’re going to set her free.”

Discovery’s astronauts will be doing the gift-giving this afternoon as they return the Hubble Space Telescope
to orbit, allowing it to continue its astronomical observations. About 1:45 p.m. CST, European Space
Agency astronaut Jean-Francois Clervoy will use Discovery’s robot arm to firmly grasp the telescope. After a
series of commands to disconnect from external power and confirm Hubble is ready for release, Clervoy will
gently lift it out of the support structure in Discovery’s payload bay where it has rested since he first plucked
it from orbit on December 21. The telescope’s aperture door will be commanded open and at 4:50 p.m.,
Clervoy will release the upgraded telescope.

Hubble’s capabilities were enhanced over the course of three spacewalks, lasting a combined total of 24
hours, 33 minutes. Spacewalking astronauts Steve Smith, John Grunsfeld, Mike Foale and Claude Nicollier
installed six new gyroscopes, six Voltage/Temperature Improvement Kits, a new more efficient computer,
and a refurbished Fine Guidance Sensor. Functional checks and tests of the hardware indicate that the new
equipment is working properly and will further enhance the Hubble’s scientific capabilities.

This afternoon, the spacewalking team, including arm operator Clervoy, will take a break from their duties to
discuss the progress of the mission so far in a series of interviews with CNN, the Associated Press and the Fox
News Network. That interview is scheduled for 7:12 p.m. today.

Discovery is in an orbit with a high point of 380 miles and a low point of 363 miles with all systems on
board performing well.

The next status report will be issued at 11 p.m. or as events warrant.

###