ACE Weekly 12/02/2015 - 12/08/2015

All ACE spacecraft subsystems are performing as expected.

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Attitude/Orbit:

Type               Attitude
Date             12/08/2015
DOY                342 2015
Thrusters        2R 4R+ 4R-
Duration       6:04 minutes
Start             14:02:42z
Stop              14:08:46z
ra,decStart    254.93,-8.48
ra,decStop     260.51,-8.68
ra,decExpect   260.75,-8.81
Deviation          0.27 deg (-4.2%)
HGAStart          -8.91 deg
HGAStop            9.05 deg
SunStart          14.27 deg
SunStop           15.17 deg
SpinStart        5.0409 rpm
SpinStop         5.0424 rpm
Nutation           0.05 deg
Firing            31 pulses
FuelUsed         0.1006 lbm
FuelRemain      94.0276 lbm
FinalSCMass    1328.288 lbm

Upcoming Maneuver Schedule:

- Attitude maneuver:		Tuesday, 12/15/2015
- Station-keeping maneuver:	Tuesday, 01/05/2016

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OCRs:

None

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Activities:

Data Capture: 100%  DOY 333-340 2015


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Anomalies:

DOY 342 (12/08/15) SOAR S-ACE-45: Autonomy Bin Dump Miscompares

- Autononmy Bin 41 miscompare notification received during daily end of
pass state of health verification activities.

IMPACT:

No impact to automated pass operations. FOT verified correct autonomy bins
were disabled (41) and enabled (42) based on current SSR in record (SSR
B).  The ace gri was updated nominally via automation during the DOY 343
contact.

Background:

- The SSR failover Bins (41 and 42) are enabled/disabled daily and the ACE
ground reference image (GRI) is updated with the latest corresponding bin
state.

- Once the nominal SSR swap had occurred and SSR B had been placed in
record, Bin 41 and Bin 42 were commanded on the S/C to disable and enable
states, respectively.

- The Bin 41 and 42 states were scheduled to be updated sequentially in
the GRI. However, the Bin 41 GRI update process did not complete
nominally.
  
- A preliminary investigation suggests the ace_gri updating procedure
encountered an (infrequent) execution issue due to the "race" conditions
setup during the automated running of the ace_gri script (i.e, the Bin 41
GRI update process starts, but does not end before the start of the Bin 42
GRI update).  

- The FOT will submit a MOCR to update the operational procedure with a
"WAIT until" completion condition. However, given the relatively low
occurrence of this issue (last occurrence was on 2014 DOY 308) the
procedure will be updated once the need for another procedure update is
required.