Two More Glitches Surface While Starting Up Backup System
The National Space and Aeronautics
Administration's latest efforts to return the Hubble Space
Telescope to functionality were thwarted Thursday by two
malfunctions encountered in an attempt to restart observation
components through backup systems.
The latest problems involve a low voltage power supply to one of
Hubble's cameras and a glitch in an onboard computer.
The Associated Press reports the soonest Hubble could be
operating fully again is late this week. Art Whipple, a Hubble
manager, said at worst, the observatory might remain inactive until
astronauts arrive with replacement parts on the next Shuttle
mission, scheduled for February 2009.
"We're still optimistic," he told reporters Friday.
NASA said that on Wednesday, October 14, engineers at NASA's
Goddard Space Flight Center reconfigured six components of the
Hubble Data Management System and five components in the Science
Instrument Command and Data Handling (SIC &DH) system to use
their redundant (or B) sides.
This was done to work around a failure that occurred on
September 27 in the Side A Science Data Formatter in the SIC&DH
and resulted in the cessation of all science observations except
for astrometry with the Fine Guidance Sensors.
The reconfiguration proceeded nominally and Hubble resumed the
science timeline at Noon ET on Thursday, October 16. The first
activities out of that on-board science timeline were the
commanding of the science instruments from their safe to operate
modes.
This occurred nominally for Wide Field Planetary Camera 2 and
the Near Infrared Camera and Multi Object Spectrometer. However, an
anomaly occurred during the last steps of the commanding to the
Advanced Camera for Surveys.
At 1:40 pm, when the low voltage power supply to the ACS Solar
Blind Channel was commanded on, software running in a
microprocessor in ACS detected an incorrect voltage level in the
Solar Blind Channel and suspended ACS.
Then at 5:14 pm, the Hubble spacecraft computer sensed the loss
of a "keep alive" signal from the NASA Standard Spacecraft Computer
in the SIC&DH and correctly responded by "safing" the NSSC-I
and the science instruments. It is not yet known if these two
events were related.
The investigation into both anomalies is underway. All data has
been collected and is being analyzed. "We're in the early stage of
going through a mountain of data that has been downloaded over the
last 24 hours," Whipple said.
The science instruments will remain in safe mode until the
NSSC-I issue is resolved. All other subsystems on the spacecraft
are performing nominally and astrometry observations continue.