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.