The Hubble Space Telescope

Unlocking the Secrets of the Universe

Daily Report #5773

Period Covered:
08:00 pm May 3, 2012 - 07:59 pm May 4, 2012
(DOY 125/0000z - 125/2359z)

Flight Operations Summary

This report was generated by the HST Automated Report System @2012-05-05 17:02:00 GMT

Significant Spacecraft Anomalies: (The following are preliminary reports
of potential non-nominal performance that will be investigated.)

HSTARs:
none

COMPLETED OPS REQUEST:
none

COMPLETED OPS NOTES:
none

FGS ACQ STATUS:
		    SCHEDULED       SUCCESSFUL
FGS GSAcq		7		7
FGS REAcq		8		8
OBAD with Maneuver	3		3

SIGNIFICANT EVENTS:
Flash Report:  COS Suspend:  HSTAR 13305  An Anomaly Status Briefing was held on Friday, May 04, 
2012 to discuss the current status of the investigation into the COS suspend event that took place 
on day 121.  Attendees included, in addition to the STScI and GSFC teams, members of the University 
of Colorado COS Instrument Science Team and Principal Investigator, and the UC Berkeley team that 
built the COS FUV detector and many similar detectors on-orbit. The following information 
summarizes the anomaly briefing.  1.      Updates to Presentation:  Two chart packages were used 
for this meeting.  
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S_Suspend_2012.04.30/COS%20Status%20Review05_4_12/COS%20Suspend_May_04_12_Status_Briefingrev1.pptx> 
package contains all the presentations but is currently missing an animation of the event that was 
provided in 
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maly_Info/COS_Suspend_2012.04.30/COS%20Status%20Review05_4_12/120504_COS_Status_Review_togsfc.pptx> 
set of charts that contains the STScI input. Note that the animation in the second presentation may 
not operate properly on a Windows machine.  The file is also about 50MB in size.  A file containing 
only the animation can be found 
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 It should run properly on a Windows machine.  The first presentation will be updated to reflect 
the order that the charts were presented.  2.      Action Items:  Action 1 -  Investigate history 
to determine why the flight code was changed between STIS and ACS in the handling of error 
conditions of this type. Assigned:  Payload Flight Software   Status:  Open   3.      Waiver 
Approvals:  N/A  4.      Discussion/Agreements:  The meeting was convened with the primary purpose 
of presenting the latest analysis results and to obtain approval to proceed next week to command 
the COS to operate and to begin recovery of the NUV.  The MOSES II SI system engineers, STScI 
instrument engineers, and the COS team presented the results of their analysis and were of the 
unanimous opinion that it was safe to proceed with the plan to bring the NUV up in a controlled 
manner.  Mike Kelly of the SI Flight Software team presented the results of the investigation into 
the software behavior during the event.  It was determined that the DIB responded properly to the 
error condition generated by the high count rate event.  This was verified in a test in the VSTIF 
using the COS bench.  He recommended that an SCR be written to correct the logic which resulted in 
the 803 error.  An investigation into the history of this code is required to determine why it was 
changed between STIS and ACS (and was carried forward to COS) before this change can be made.  Tom 
Wheeler and Merle Reinhart of the STScI presented the plan for recovering the NUV. The commanding 
will be executed from stored commanding over a four day period beginning Monday morning local time. 
 A real-time command to clear an event flag will be required before each segment to allow the test 
to proceed.  The Project granted approval to proceed with this plan. 5.      Liens:  None, 
investigation is still underway.