ACE Weekly 09/30/2015 - 10/07/2015

All ACE spacecraft subsystems are performing as expected.

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Attitude/Orbit:

Type               Attitude
Date             10/07/2015
DOY                280 2015
Thrusters        2R 4R+ 4R-
Duration           10:22 minutes
Start             18:34:00z
Stop              18:44:22z
ra,decStart    189.46,-19.58
ra,decStop     199.54,-21.83
ra,decExpect   199.84,-22.09
Deviation          0.33 deg (-3.3%)
HGAStart         -10.48 deg
HGAStop           10.05 deg
SunStart          14.51 deg
SunStop           17.60 deg
SpinStart        5.0347 rpm
SpinStop         5.0375 rpm
Nutation           0.13 deg
Firing            53 pulses
FuelUsed         0.1634 lbm
FuelRemain      95.3704 lbm
FinalSCMass    1329.631 lbm

Maneuver Scheduling:

Next attitude maneuver: Wednesday, 10/14/2015
Next station keeping maneuver: Wednesday, 10/14/2015

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OCRs:

Reminder/Update on ACE-355: Relaxing the ACE antenna constraint from 9
to 11 degrees for the 2015 Summer Campaign.

The 2015 Summer Campaign, which started on 5/19/2015, will conclude
with the 10/20/2015 attitude maneuver.  The return to the 9 degree
upper limit antenna constraint will allow ACE to resume operations
with WS1.


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Activities:

Data Capture: 99.9717%  DOY 270-277 2015

Notes:

The DOY 274 DSS-34 pass was lost (see anomaly section below),
and SSR fail-overs were performed on DOY 275 (at 275-10:14:23.3 UTC)
and DOY 277 (at 275-05:12:02.06 UTC). The SSR failover transitions
are responsible for 63 seconds of data loss.

An additional 128-sec data gap was identified for (VC4) playback data
during the 276-17:14:39 (UT) - 276-17:16:46 (UT) time window.

Inspection of the DOY 276 event log and the DSN DR system does not
yield any ground system problems which correlates with the 128 sec
data gap.

Per standard procedure, the FOT will investigate further and retrieve the
corresponding IDR data, to confirm if there are any differences
from the MOC-acquired SLE data.


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Anomalies:

-SOAR S-ACE-37 - Pass loss due to hardware issue at DSS-34 (DR #C111407).

The Ops chief informed the FOT prior to the DSS-34 contact that the
DSS-34 transmitter was declared RED and the pass would be lost.

Impact: Minimal. The FOT assessed the impact of the SSR data management
(downstream the schedule) identified contact scheduling changes to
avoid data losses (i.e., converting some ranging-only passes to
tracking) and worked with the SSMO Scheduling Team to implement the
changes. There are only 63 seconds of expected data losses due to the
SSR failover transitions, as described above.

Barring some additional ground system problems, the FOT expects to be
fully caught-up by DOY 283 (Saturday, Oct-10).