ACE Weekly 07/22/2015 - 07/28/2015

All ACE spacecraft subsystems are performing as expected.

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Attitude/Orbit:

Type               Attitude                   SK-76
Date             07/28/2015                07/28/2015
DOY                209 2015                  209 2015
Thrusters        2R 4R+ 4R-                  3A  4A
Duration       7:27 minutes                53 seconds
Start             13:45:46z                 14:50:45z
Stop              13:53:13z                 14:51:38z
ra,decStart    120.30,33.05              117.79,26.43
ra,decStop     117.79,26.43              117.80,26.43
ra,decExpect   117.65,26.29              117.81,26.43
Deviation          0.17 deg (-2.4%)
HGAStart         +10.82 deg                 -4.09 deg
HGAStop           -4.09 deg                 -4.08 deg
SunStart          15.42 deg                 11.59 deg
SunStop           11.59 deg                 11.60 deg
SpinStart        5.0201 rpm                5.0215 rpm
SpinStop         5.0215 rpm                5.0096 rpm
Nutation           0.19 deg                   .12 deg
Firing            38 pulses                Continuous
FuelUsed         0.1213 lbm                0.1738 lbm
FuelRemain      97.1800 lbm               97.0062 lbm
FinalSCMass    1331.440 lbm             1331.2662 lbm

- The next attitude maneuver is scheduled for Tuesday, 08/04/2015

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OCRs:

None

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Activities:

Data Capture:  100%  DOY 200-207 2015

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Anomalies:

-  SOAR S-ACE-32: ITOS Event-log Overflow Error

At approximately 2015:205:13:25 (UT), while the DSS-65 contact was
in-progress, an additional ITOS context/session was inadvertently started
on the operational machine (mmocops1b) by the FOT, which triggered an event
log overflow scenario (i.e., set of re-occurrent ITOS command graph error
messages was triggered and increasing w/o bound). The problem impacted the
MUS commanding process and the itos_event_do_action function (i.e., a
script used as part of the MMOC alert notification system), rendering both
capabilities as inoperable. To fix the problem, per standard operating
procedure, the FOT "killed" the ace_pass STOL procedure, re-started ITOS,
re-initiated the ace_pass procedure, and itos_event_do_action, accordingly.

Following the re-start of ace_pass operations and the reacquisition of ACE
spacecraft telemetry, the FOT confirmed that SSR-B playback processes had
completed as planned (completed before the problem was encountered), with
no data gaps identified, and manually performed some of the routine
cleanup (post-pass) processes, to ascertain a clean state and correct
configuration in preparation for subsequent ACE operations.  This included
a manual generation of the SSR dump list, ACE event log, pass summary and
the clock calibration Report.

As a follow-up action, the FOT will investigate a way to mitigate the
non-standard initialization of an ITOS session on the operational systems.

IMPACT:

Minimal ­ Manual intervention by the FOT was required to perform cleanup
activities. Note: There was no data loss during this anomaly. The FOT
compared the DOY 205 IDR and SLE files and confirmed that 100% of the
DOY 205 data was captured.