SeaWiFS telemetry anomoly

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SeaWiFS telemetry anomoly

by OB.DAAC - SeanBailey » Thu Jan 03, 2008 9:00 am America/New_York

To all SeaWiFS data users:                                                               
                                                                                         
Please see the message from GeoEye (below) regarding OV-2 telemetry.  At the             
first GAC scene of 2008, the spacecraft telemetry were found to be invalid,              
and the problem has not been corrected.  This is affecting data processing               
because there are no valid GPS or attitude data to use for navigation.                   
Efforts are underway at the SeaWiFS Project to reprocess the data, however,              
navigation will be substantially degraded because of the lack of attitude                
knowledge, and there does not appear to be any possibility of recovering                 
this.                                                                                    
                                                                                         
Updated information will be provided as it becomes available.                            
                                                                                         
Fred Patt                                                                                
                                                                                                                                                          
                                                                                       
  At year rollover, OV-2 began to experience a telemetry collection                       
anomaly.  Imagery looked okay, however the ancillary telemetry was                      
invalid.  A GIM hard boot did NOT remedy the anomaly.  Loads are on                     
board through DAY 005.  Imaging will continue.     
                                    

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SeaWiFS telemetry anomoly

by OB.DAAC - SeanBailey » Fri Jan 04, 2008 8:37 am America/New_York

The OV-2 spacecraft was commanded into Safe Haven last night, and the                    
SeaWiFS instrument was powered off and stowed, as GeoEye continues to                    
investigate the loss of GPS and attitude data in the spacecraft telemetry.               
                                                                                         
Updates will be provided as they become available.    

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SeaWiFS telemetry anomoly

by OB.DAAC - SeanBailey » Fri Jan 11, 2008 11:19 am America/New_York

Message from Gene Feldman on January 11th, 2008:

good morning,                                                                            
as of friday morning, seawifs is still in a commanded safe haven                         
condition with all systems healthy.  analysis of the available                           
telemetry data has pointed to a potential source of the initial                          
anomaly and a set of diagnostic and subsequent corrective actions are                    
being developed.  extra care is being taken to make sure that the                        
solution that is ultimately implemented is the best one for the                          
long-term rather than just a quick fix since we all hope to get many                     
more years of valuable data out of this remarkable little spacecraft.                    
the important thing to remember is that the initial problem appears                      
to be the result of an onboard "hiccup" in the software which may                        
have had an impact on the handling on the stored attitude control                        
telemetry on the spacecraft and NOT a hardware failure on either the                     
spacecraft or the seawifs instrument.   the fact that the spacecraft                     
and instrument were still performing exactly as they were supposed to                    
even after the event and that the only indication of a problem was                       
the absence of the telemetry information that was needed for                             
subsequent processing of the data is a very good sign, at least to                       
these non-engineer's mind.  my hope is that we will have a better                        
sense of the path ahead and the schedule to accomplish it by early                       
next week.  i will keep everyone posted as new information becomes                       
available.                                                                               
regards for now,                                                                         
gene                       

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SeaWiFS telemetry anomoly

by genecarlfeldman » Tue Jan 22, 2008 6:38 pm America/New_York

Message from GeoEYE on January 22, 2008:

"On January 1, 2008, beginning with OrbView-2's first imagery collection
of the New Year, ancillary data associated with the imagery such as GPS
and satellite attitude information stopped being included in the
downlink.

As a result the imagery data cannot be geo-positioned, rendering it
unusable for scientific research purposes.  OrbView-2 has been removed
from imaging operations for troubleshooting and diagnostics.

GeoEye remains in daily communication with OrbView-2, the satellite is
in a safe condition, and we are optimistic regarding returning OrbView-2
to service.

We have investigated the performance observations and have established a
resolution plan.  This process, while time-consuming, has been performed
using the diligence and thoroughness necessary with an aging satellite.
We are finalizing the specifics of that plan to ensure that our future
actions are well-developed to restore the OrbView-2 satellite into
operations supporting the mission of the ocean color community with
minimal risk.

We anticipate resolving this issue within the next several days, and
will let you know as soon as the status changes."

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SeaWiFS telemetry anomoly

by OB.DAAC - SeanBailey » Fri Feb 08, 2008 8:27 am America/New_York

here is the latest information from geoeye regarding the status for                      
the planned restoration of routine seawifs imaging operations.                           
hopefully, we'll have some specific and positive news to pass along                      
next week.  a large, collective crossing of fingers would be most                        
appreciated.                                                                             
regards,                                                                                 
gene                                                                                     
                                                                                         
                                                                                         
Dear OrbView-2 SeaWiFS Users,                                                            
                                                                                         
GeoEye remains in daily communication with OrbView-2, the satellite                      
and SeaWiFS sensor are in a safe condition, and we continue to be                        
optimistic regarding returning OrbView-2 to service.                                     
                                                                                         
We continue to make progress on finalizing a recovery plan and will                      
advise when there is a change in operational status.                                     
                                                                                         
We appreciate your patience during this process.                                         
                                                                                         
Best Regards,                                                                            
                                                                                         
GeoEye 

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SeaWiFS telemetry anomoly

by OB.DAAC - SeanBailey » Wed Feb 27, 2008 8:56 am America/New_York

The following is an update on the status of SeaWiFS from GeoEye.

February 27th, 2008  03:26 EST:

I am happy to report we successfully switched to SCC-2 on OV-2 during                    
our 1st contact this evening.  On the 2nd contact we performed the GPS                   
receiver commanding.  Everything looks nominal except for a few                          
callback "odditities" which we need to investigate further Wednesday                     
morning.  We are now on SCC-2 and it is functional with a date of                        
1/1/1994.                                                                                
                                                                                         
On our 1st daytime contact on 2/27/08, we'll assess the GPS receiver                     
status as well as review the entire spacecraft telemetry.  However, as                   
of right now, Phase 1 of our SCC Switch and recovery as documented in                    
our SCC Switch procedure, is completed.  We just need to see what                        
clean up commanding may be necessary.

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SeaWiFS telemetry anomoly

by OB.DAAC - SeanBailey » Wed Mar 12, 2008 8:49 am America/New_York

Message from March 11th, 2008:

good evening,                                                                            
i am very happy to be able to report that as of late this afternoon,                     
the geoeye ground controllers commanded seawifs to resume routine                        
imaging operations and the first hrpt pass over the united states                        
west coast has been received and looks good.  the real test will be                      
tonight at which time we hope to receive the first s-band downlink                       
containing the first complete orbits of data since the beginning of                      
the new year.  once that pass is received and processed successfully,                    
i think that we can all breathe a collective sigh of relief.                             
thanks for hanging with us during this long, difficult, and at times                     
nerve wracking experience.                                                               
regards,                                                                                 
gene                                                                                     

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SeaWiFS telemetry anomoly

by OB.DAAC - SeanBailey » Thu Mar 13, 2008 10:33 am America/New_York

Message from March 13th, 2008:

folks,                                                                                   
just a quick note to say that seawifs decided that it wasn't quite                       
ready to come out of early retirement and went out of imaging mode                       
soon after the successful data downlink that i reported yesterday                        
morning.  the good news is that the source of this anomaly is                            
understood and corrective actions are currently underway.                                
just make sure that your seatbelts are fastened and stay in your                         
seats because the roller coaster ride isn't quite over yet.  will                        
keep you posted as information becomes available.                                        
regards,                                                                                 
gene                

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SeaWiFS telemetry anomoly

by genecarlfeldman » Mon Mar 17, 2008 1:13 pm America/New_York

Update as of 17 March 2008:
Work continues on returning SeaWiFS to full imaging mode although a target date for that to happen has not been established.  At this time the spacecraft and instrument are fine and a series of table updates to the onboard software are being carried out to restore all the parameters to pre-anomaly values.  Once that has been done and verified, I would anticipate that a schedule for resumption of imaging will be decided upon.  Will keep you posted as new developments warrant.
Regards,
gene

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SeaWiFS telemetry anomoly

by genecarlfeldman » Thu Mar 27, 2008 3:25 pm America/New_York

Update as of 27 March 2008:
Work continues on returning SeaWiFS to full imaging mode although a target date for that to happen has not been established.  At this time the spacecraft and instrument are fine, the spacecraft power system is normal, GPS tracking has been restored and a series of table updates to the onboard software are being carried out to restore all the parameters to pre-anomaly values.   As yet, however, there is no definitive schedule that has been provided for resumption of imaging.  Non-critical updates will be posted to the Ocean Color Announcements section on the OceanColor forum as they become available at:

http://oceancolor.gsfc.nasa.gov/forum/oceancolor/forum_show.pl

but any major change in the situation will be sent via e-mail to the oceancolor mailing list.

I'll keep you posted as new developments warrant.
Regards for now,
gene

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