Hubble Problems

18 10 2008

Engineers at the Goddard Space Flight Center in Maryland have hit two
new snags in their effort to repair the Hubble Space Telescope after a
major equipment failure in space last month.

This problem began September 27 with the failure of Hubble’s Science
Instrument Control and Data Handling (SIC&DH) system. The on-board
computer coordinates commands to the satellite’s various instruments
and then downlinks the scientific data to the ground. While that
computer is down, most science observations are at a standstill.

The system was built with a fully redundant backup channel called “Side
B,” designed to come online in the event “Side A” ever failed. Hubble
team members at Goddard began a complicated process on Wednesday to
send computer commands to the telescope to switch over to Side B, and
hoped to have everything completed by midday Friday.

More problems began to pile up…

Early in the afternoon, there were problems powering up one of Hubble’s
instruments, the Advanced Camera for Surveys, though other instruments
turned on normally.

Later in the evening, a communications failure between multiple onboard
computers put all the science instruments, including the main science
computer, into safe mode. It is unclear how these problems are related
to each other or the activation of the SIC&DH Side B channel.

Even if the switch over to the Side B backup ultimately fails, Hubble
managers say the design team had the foresight 20 years ago to build a
spare SIC&DH system, which has been warehoused at Goddard all this
time while the original instrument perked along just fine.




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