ACE Weekly 11/13/2014 - 11/18/2014

Refer to the anomaly section for updates to the fuel system
temperatures.  All other ACE spacecraft subsystems are performing as
expected.

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Orbit/Attitude:

	Type          Attitude
	Date         11/18/2014
	DOY           322 2014
	Thrusters     2R 4R+ 4R-
	Duration       8:45 min
	Start         16:36:54z
	Stop          16:45:39z
	ra,decStart  239.79,-9.97
	ra,decStop   247.38,-9.82
	ra,decExpect 248.34,-10.07
	Deviation      0.98 deg (-11% short)
	HGAStart      -9.16 deg
	HGAStop       +8.87 deg
	SunStart      11.05 deg
	SunStop       16.31 deg
	SpinStart    5.0023 rpm
	SpinStop     5.0040 rpm
	Nutation       0.08 deg
	Firing        44 pulses
	FuelUsed       0.1399 lbm
	FuelRemain   102.6120 lbm
	FinalSCMass  1337.872 lbm

The next attitude maneuver is scheduled for Tuesday 11/25/2014.

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OCRs:

None

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Activities:

Data Capture:  100%  DOY 313-320 2014


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Anomalies:

DOY 318  11/14/2014  S-ACE-0689  ITOS Command Graph Error
The ITOS ground system generated an error early in the pass.  (Command
transmission has failed: dbus synchronous send/await: Message did not
receive a reply)  No further commanding (including playback of recorded
data) was performed during the pass.  ITOS was manually restarted after
the pass.  This is an occasionally recurring problem that last occurred
09/26/2014.
IMPACT:  Playback of recorded data slowly caught up over the next 4
passes.
 

Update for S13-0001 - B1/B2 Fuel Tank Temperature Anomaly

As reported last week (11/12/2014) and in previous reports:

* Starting 10/14/2014, the tank heaters started cycling off.  The Tank
B1 temperature fluctuates ~4C as the tank heaters turn on and off.  The
other tank temperatures remain within 1C.

* During the 11/5/2014 and 11/12/2014 maneuvers, the Tank B2 temperature
increased and the -X External Fuel Line temperature decreased.  The
timing corresponded to the start of the maneuver and no heaters turned
on/off at that time.  When the maneuver had stopped, the temperatures
returned to their normal temperatures over ~10 minutes.


Updates for this week (11/18/2014):

* Starting after the 11/12/2014 maneuver, the Tank B2 temperature has
been fluctuating ~2C as the tank heaters turn on and off.

* During the 11/18/2014 maneuver, the Tank B2 temperature did not
increase as had happened on 11/5 and 11/2.  But the -X External Fuel
Line did decrease.  Again, the timing corresponded to the start of the
maneuver and no heaters turned on/off at that time.  When the maneuver
had stopped, the -X External Fuel Line returned to its normal
temperature.


The fuel system temperatures continue to be monitored.  There is not yet
a theory to explain the temperature changes in the Tank B2 temperature
or the -X External Fuel Line temperature.