ACE Weekly 06/19/2012 - 06/25/2012
All ACE spacecraft subsystems are performing as expected.
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Orbit/Attitude:
Type Attitude
Date 06/22/2012
DOY 174 2012
Thrusters 2R 4R+ 4R-
Duration 15:22 min
Start 14:38:38z
Stop 14:54:00z
HGAStart -6.77deg
HGAStop +7.57deg
SunStart 6.51deg
SunStop 18.17deg
SpinStart 5.0547rpm
SpinStop 5.0591rpm
Nutation 0.14deg
Firing 78 pulses
FuelUsed 0.2380lbs
FuelRemain 120.9256lbs
FinalSCMass 1355.186lbs
The next attitude maneuver is scheduled for Thursday 07/12/2012.
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OCRs:
DOY 173 (06/21/2012) 1823-1826z SWPE-043 Overcount Threshold ->0x80
DOY 177 (06/25/2012) 1638-1640z SWPE-043 Overcount Threshold ->0xFF
The SWEPAM-Electron overcount alarm had been flagging ~45% of the time
in April and May 2012. It has been flagging almost continuously in June
2012. The instrument team has increased the overcount threshold. The
following table shows the SWEPAM-Electron overcount threshold over the
years.
Date Threshold Notes
---------- --------- -------------------------------------------------
original 0x04 1024 overcount: 5 days out of ~4000 days (1997-2001)
10/04/2001 0x03 768
11/15/2001 0x02 512
11/30/2001 0x01 256 overcount: 5 days out of 246 days (2001-2002)
06/07/2002 0x80 128 flight code 1.14 changes threshold step size
previous 0x01 = 256; current 0x80 = 128
overcount: 11 days out of ~1200 days (2002-2005)
10/07/2005 0x20 32 lowered for solar minimum
overcount: 5 days out of ~2300 days (2005-2011)
overcount flagging increases starting 1/22/2012
06/02/2012 0x40 64 overcount starts flagging almost continuously
06/21/2012 0x80 128 overcount continues flagging almost continuously
06/25/2012 0xFF 255 waiting for next week's data
With the threshold of 0x80 set last Thursday (6/12), the overcount
threshold continues to flag almost continuously. This is the same
threshold used from 2002-2005 when the overcount alarm flagged on only
11 days over 3 years. The instrument team will need to discuss other
options if the 0xFF threshold does not stop the overcount alarm.
The instrument is still collecting science. The overcount threshold
reduces voltages to extend the life of the instrument.
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Activities:
Data Capture: 100% DOY 169-176 2012
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Anomalies:
None