ACE Weekly 05/17/2011 - 05/23/2011

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

	Type        Attitude
	Date        05/17/2011
	DOY         137 2011
	Thrusters   2R 4R+ 4R-
	Duration    14:26 min
	Start       15:39:31z
	Stop        15:53:57z
	HGAStart    -8.20deg
	HGAStop     +7.54deg
	SunStart     9.56deg
	SunStop      7.46deg
	SpinStart   5.0862rpm
	SpinStop    5.0901rpm
	Nutation     0.13deg
	Firing      74 pulses
	FuelUsed      0.2319lbs
	FuelRemain  128.8988lbs
	FinalSCMass 1363.159lbs

The next attitude maneuver is scheduled for Thursday 05/26/2011.

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OCRs:

None


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Activities:

Data Capture:  100%  DOY 135-142 2011

Update on NOAA Space Weather Prediction Center tracking of ACE
DLR (Germany) started tracking ACE again on May 18.  The closest
Sun-Earth-Vehicle (SEV) angle was on May 19 with 1.41 degrees and DLR
did not have problems.  However, NICT (Japan) has been down since
Tuesday May 17 due to failure of their air conditioner.  There are
problems getting a replacement due to ongoing problems from the March
11, 2011 earthquake.  At best, it'll be 1-2 months before NICT's antenna
is back up.  This causes a ~4.5 hour gap (2330-0400) between coverage
from Wallops (WCDA) and Germany (DLR).  NOAA SWPC is investigating using
other antennas including the Near Earth Network (NEN) Alaska Satellite
Facility (ASF) and the NOAA's Gilmore Creek Facility.  Note, the NOAA
SWPC operations are separate from the Goddard flight operations, but
this information is worth noting and therefore included in this weekly
report.


Update on SEPICA Temperatures.
The following is an updated table with instrument deck temperatures with
SEPICA ON and OFF.  The SEPICA ON temperatures were averaged over 44
days and the SEPICA OFF temperatures were averaged over 25 days.  The
days were picked to match the same sun distance and sun angle.  There
will be some error in these numbers and other affects, including the
continual insulation degradation.  However, we expect that these numbers
are close to the actual temperature changes due to SEPICA being powered
off.

                       ON     OFF   Diff
     SEPICA_IF_T       36.1   25.2  10.9
     SEPICA_BASEPL_T   31.8   23.0   8.7
     CNTR_IDECK_T      26.4   22.6   3.8
     ULEIS_IDECK_CNTR  23.1   19.9   3.2
     YP_ANTBASE_T      18.0   15.7   2.4
     YP_XM_IDECK_T     16.0   13.7   2.3
     S3DPU_PS_A_T      41.7   39.8   1.9
     S3DPU_PS_B_T      40.4   38.6   1.8
     SWPE_IF_T         13.0   11.4   1.6
     SWPE_INT_T        18.5   16.9   1.6
     ULEIS_ANLG_E_T    28.9   27.2   1.6
     MAG_PCTEMP        40.4   38.4   1.9
     MFI_IDECK_T       21.2   19.6   1.6
     XP_YP_IDECK_T     10.1    8.7   1.4
     AE_IDECK_T        22.5   21.3   1.2
     ULEIS_DPU_T       23.6   22.5   1.0
     SIS_IDECK_EDGE    12.0   11.4   0.7
     XP_EDGE_IDECK_T    9.8    9.2   0.6
     ULEIS_SCOPE_T      6.1    5.5   0.6
     ULEIS_IF_T         3.3    2.7   0.6
     SWICS_IF_T         6.3    5.8   0.5
     YP_XM_TOP_CNTR_T  11.1   10.1   0.9
     SIS_IF_T          24.4   24.6  -0.2

SEPICA ON
	DOY 111-115, 120-136 and 234-257
	Average Sun Distance 149404225.0 km
	Average Sun Angle    7.9 deg

SEPICA OFF
	DOY 111-136 2011
	Average Sun Distance 149378062.3 km
	Average Sun Angle    7.8 deg
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Anomalies:

DOY 140  05/20/2011  S-ACE-0610  G11-0037  SLE Command Negative
DSN has a known issue that their command system occasionally rejects
commands via SLE.  When this occurs, the MMOC needs to manually
disconnect and reconnect SLE FCLTU.  The command negative problem last
occurred on 04/29/2011. (AR#G11-0034).
IMPACT:  Manual intervention required for commanding.

DOY 142  05/22/2011  S-ACE-0611  G11-0038  D27 Power Outage
The DSN ground station was experiencing a power outage at ACE's
Beginning Of Track (1455z).  Power was restored at 1605z and telemetry
was online at 1739z.  The MMOC automation initiated commanding.
However, no VC2 (playback) data was received in the MMOC and no data was
available at DSN's DCD.  DR#G111540
IMPACT:  Manual intervention on Monday (DOY 143) to redump the data
missing from DOY 142.  It will take ~3 days to catch up on the SSR
playback.  A 31 second gap will occur on DOY 144 due to the expected SSR
failover.