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Johnson
Space Center STS-103 Report # 09 Friday, December 24, 1999,
12:30 AM EST
The
Hubble Space Telescope received a new advanced computer Thursday
from space-walking Discovery astronauts Mike Foale and Claude
Nicollier. Their 8-hour, 10-minute space walk, the third longest
in history, also saw replacement of a 550-pound fine guidance
sensor.
Flight
controllers said all major activities of the space walk, the
second of three on consecutive days of Discovery's space telescope
repair and improvement mission, had been accomplished. Controllers
reported that power was reaching both of the new pieces of
equipment.
"The
brains of Hubble have been replaced," said Mission Specialist
John Grunsfeld, who worked Thursday in Discovery's cabin with
the space-walking crew members outside. About 30 minutes later
Hubble began thinking with those new brains. At an evening
mission status briefing, John Campbell, Hubble Space Telescope
program manager, said the functional checkout of the new computer
showed it was functioning well. Checkout of the Fine Guidance
Sensor, is continuing.
The
length of Thursday's space walk made it the third longest
in history, behind only the 8-hour, 15-minute effort on Wednesday
by Payload Commander Steve Smith and Grunsfeld and an 8-hour,
29-minute space walk by three Endeavor astronauts on STS-49
on its Intelsat rescue mission in May 1992.
Replacement
of one of Hubble's two S-band transmitters is a highlight
of Friday's space walk by Smith and Grunsfeld. The transmitter
to be replaced had failed. The second transmitter was able
to carry the load alone, so no science was lost. The transmitters
are considered very reliable, and unlike most of the equipment
aboard Hubble, they were not designed to be changed out in
orbit. Special tools were developed to enable astronauts to
do the job more easily. Installation of a Solid State Recorder
to replace a less reliable and less capable 10-year-old recorder
is the second major item on the schedule.
Also on the timeline of the space walk, scheduled to begin
at 1:50 p.m. CST, is installation of new insulation on equipment
bay doors. The spacewalk could, like its two predecessors
on STS-103, begin earlier if the crew completes preparations
early. Flight controllers are anxious to end this third space
walk at 8 p.m. as scheduled.
Discovery remains is in excellent condition, in an orbit with
a high point of 380 statute miles and a low point of 364 miles.
The next status report will be issued at 11 a.m. Friday, or
as events warrant.
Hubble
Project Update, Thursday, December 23, 9:30 PM EST
Mike
Foale and European Space Agency astronaut Claude Nicollier
got an early start today in the second successful spacewalk
of the mission. The crew installed Hubble's new main computer
and replaced one of the telescope's three Fine Guidance Sensors.
Foale and Nicollier also installed a new thermal blanket layer
over Bay 1, which houses the main computer.
The
new computer is 20 times faster with six times the memory
of the outdated unit it replaces. The enhanced Fine Guidance
unit flew on Hubble before--it was removed on STS-82 during
the Second Servicing Mission in February 1997 and refurbished.
Hubble uses three Fine Guidance Sensors to precisely point
as it conducts scientific observations.
Foale has walked in space twice before, during the STS-63
mission in February 1995 and again in September 1997 on his
mission to Mir. Nicollier visited Hubble in December 1993
aboard STS-61, the first servicing mission to Hubble. On that
mission, he controlled the Shuttle's robotic arm. Today was
his first spacewalk.
Space
Telescope Operations Control Center Update
UPDATE NO. 4 (Rev. 1)
Thursday, Dec. 23 1999 - 3:30 p.m. EST
A
lot of smiles here in the STOCC today after yesterday's very
successful replacement of all six of Hubble's gyroscopes.
The STOCC has been very active the past 24 hours with several
thousand commands uplinked to the Hubble as part of the test
and checkout of new components installed in the Telescope
yesterday.
Immediately
after astronauts Steven Smith and John Grunsfeld installed
the three new Rate Sensor Units in Hubble, controllers conducted
an initial "aliveness" test of the gyros and they all checked
out fine.
A
more thorough functional test of the 3 units - each containing
a pair of gyroscopes - was performed after the crew went to
sleep, and those checks were also very successful.
Controllers
also completed testing of the six Voltage/Temperature Improvement
Kits, or VIKS, that the astronauts installed yesterday on
each battery. All six VIKS are working exactly as expected.
Hubble's 10-year old batteries work well, but are more susceptible
to overheating than when they were brand new. The VIKs will
prevent battery overcharging and associated overheating.
Controllers
in the STOCC are preparing for today's second space walk.
Astronauts
will install a new, more powerful 486 computer during EVA
2. To prepare Hubble for the replacement, controllers will
turn off the old computer. Once the new computer is installed,
controllers will boot it up, a procedure that takes about
an hour, and then begin several hours of detailed checks to
verify the computer is interacting properly with Hubble's
hardware and systems.
The
EVA crew will also install a new fine guidance sensor - one
of three on Hubble - which are used to provide pointing for
the Telescope and also serve as a scientific instrument for
astrometric science. This new unit is actually one that was
removed from Hubble on the second servicing mission and has
been refurbished and outfitted with an enhanced alignment
capability. Controllers will conduct a functional test of
the new guidance sensor, a task that should take about an
hour. The guidance unit that Discovery will bring home will
be refurbished and installed on the fourth servicing mission.
Ground
systems here in the STOCC continue to perform well, and controllers
here at Goddard are ready for today's space walk.
Johnson
Space Center STS-103 Report # 08
Thursday, December 23, 1999, 11:00 am EST
Discovery's
seven-member crew began work early today, preparing for a
busy day on orbit, including a second spacewalk and a final
check of hardware installed on the Hubble Space Telescope
during yesterday's spacewalk.
The
primary goal of today's spacewalk, to be conducted by Mike
Foale and European Space Agency astronaut Claude Nicollier,
is to install a new computer to replace the one currently
in use by Hubble. The new computer is 20 times faster and
has six times the memory of the outdated unit being replaced.
Nicollier and Foale also will change out one of Hubble's three
Fine Guidance Sensors that are used to precisely point the
telescope as it conducts scientific observations. The unit
being installed today is a refurbished unit that was removed
and returned to Earth by the STS-82 crew during its servicing
of the telescope in February 1997. If time permits, the space
walkers also may perform some optional tasks. Foale has conducted
two previous spacewalks, during the STS-63 mission in February
1995 and again in September 1997 as he and Mir Space Station
Commander Anatoly Solovyev conducted a six-hour survey of
the Mir. This is Nicollier's first spacewalk.
Today's spacewalk is scheduled to begin at 1:50 p.m., but
could begin earlier if the crew members complete their preparations
ahead of schedule. During the spacewalk, Foale can be recognized
by the broken red stripes on the legs of his EVA suit, and
Nicollier by the diagonally broken red stripes on his suit.
Discovery's
astronauts also supported a functional test of the voltage
temperature improvement kits, referred to as VIKs, installed
by Steve Smith and John Grunsfeld during their spacewalk yesterday.
To ensure the checkout is complete prior to the start of today's
scheduled EVA; the astronauts began the work shortly after
crew wake-up. During the 90-minute long checkout, investigators
will monitor the performance of the voltage kits as the telescope's
batteries are charged.
This morning's wake-up music honored the two space-walking
astronauts, Nicollier and Foale. Traditional Swiss music was
played for Nicollier and the song "Only When I Sleep"
by The Corrs was played for Foale.
Discovery
remains in excellent condition, in an orbit with a high point
of 380 statute miles and a low point of 369 miles. The next
status report will be issued at 11 p.m. or as events warrant.
HST
Project Update - Thursday, December 23, 8:00 am EST
Planning
is complete and all systems are ready to support EVA day 2
activities.
Extensive functional testing overnight confirms that the six
new gyroscopes are performing as expected.
Overnight,
the Hubble team was looking over the extensive amount of photographic
data we have collected. There are now over 450 photographs,
all taken over the past two days.
Once
again, our astronaut team is eager to get to work. We anticipate
another early start for EVA 2.
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