Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.stsci.edu/ops/swat/safing/03103/update1.txt Дата изменения: Mon Apr 14 22:05:37 2003 Дата индексирования: Sun Mar 2 01:20:32 2014 Кодировка: Поисковые слова: eugene cernan

Date: Sun, 13 Apr 2003 22:22:50 -0400
From: Rodger Doxsey
To: all_staff@stsci.edu
Subject: HST safemode entry

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HST went into zero gyro safemode about 6:00 local time on Sunday evening.
The safemode entry was caused by gyro 3 stalling. Per the normal procedure,
the gyro was restarted and successfully returned to operation. This is very
similar to the occurrence last Thanksgiving. We are assuming that gyro 3
will continue to work, and so the process of returning the telescope to
normal operations has begun. The science observing program will be
restarted about 10 pm on Monday evening.

The working theory for the problem with this gyro is that there are very
small particulates that occasionally get caught in the air bearing and cause
it to stall. The restart process seems to be enough to clear it out. With
an occurrence interval of 4-6 months, it seems best to keep using gyro 3 and
suffer the occassional safing, and keep the spares until needed later.

Rodger Doxsey