ACE Weekly 08/06/04 - 08/12/04

All ACE spacecraft subsystems are performing nominally.  An attitude 
maneuver was successfully executed on 08/12/04.  The next stationkeeping 
/attitude maneuver is scheduled for 08/20/04.

============================================================================
Orbit Events:

 From Craig Roberts (FDF):
The next ACE stationkeeping maneuver (SK-33) is scheduled for 08/20/04, to 
coincide with a scheduled attitude reorientation maneuver.  Thus SK-33 will 
be out of the way just as the next SEZ transit--which will have its closest 
approach to the Sun on 08/30/04 --is beginning.  The delta-V for 08/20/04 
is currently projected to be about 0.37 m/sec in the anti-Sunward 
direction.  The burn duration is estimated at 64 seconds.

ACE's Lissajous orbit has now transitioned to an opening pattern, so the 
ACE motion will now be counterclockwise about L1 (and for that matter, the 
Sun) for quite a long time to come.

=====================================================================
OCRs Executed:

None

=====================================================================
Ongoing Activities:

TAPS:
- Installation of TAPS release 4.3 is occurred on 07/20/04.  FOT testing of 
this release is ongoing.
   -- Of the 6 DRs fixed in release 4.3, 5 have been verified, 1 has failed.

- Additional DRs will be submitted for newly found problems.

----------------------------------------------------------------------------
Automation (ROBOTT):

- ROBOTT v0.7 has been used for daily operations on String 1 since Tuesday 
07/27/2004 (OCR GND-140) with ROBOTT in Advisory and Auto modes.  No data 
loss or command problems due to ROBOTT have occurred this week.

- All of the DRs fixed in ROBOTT v0.7 have been tested, 23 have been 
verified, 2 have been cancelled and 2 have failed (DR CDSID 20858 and DR 
CDSID 20870).  28 new DRs have been
written against v0.7.

- ROBOTT v0.8 was installed on Strings 2 and 3 on 08/12/04 (OCR GND_141).  The
installation on both strings facilitates testing the RTMON component. 
Testing of v0.8 by the FOT will begin 08/13/04.

============================================================================
Extra Spacecraft Activities:

None

=====================================================================
Anomalies:

DOY 04219 (08/06/04) ACE Anomaly G04-0089 - TAPS - Dropped Frames
While reviewing short term data is was noticed that TAPS drops data every 7 
minutes 9 seconds.  In addition, further investigation revealed that TAPS 
drops 3 frames of data for every bad VC2 when it should only drop 2 
frames.  IMPACT: Lost trending data.  DR to be submitted.

DOY 04220 (08/07/04) ACE Anomaly G04-0090 - ROBOTT - Software Reboot
At 13:02:47, during the procedure G_INITIAL_CONTACT,  telemetry dropped out 
from DSS-16.  Within five seconds telemetry was back online but 
G_INITIAL_CONTACT had stopped at the WAIT which checks to ensure the 
spacecraft receivers are in lock.  C&C had paused commanding.  The FOT 
waited to see if C&C would resume commanding but it didn't.  Finally, after 
several minutes the FOT entered a "go" to resume 
commanding.  G_INITIAL_CONTACT completed without any further 
problems.   However at 13:50:30, ROBOTT rebooted and came back up on String 
1.  During that reboot DSS-16 experienced a telemetry dropout from 13:58 - 
14:01 (DR#G104691).   At 14:00, everything was back up.  IMPACT:  Delay in 
daily pass activities. DR CDSID 00021024, DR# G104691

DOY 04219 (08/06/04) ACE Anomaly G04-0091 - GDS (DSS-16) TCP Reboot
The Reed-Solomon decoder at DSS-16 continues to show excessive 
corrections.  During the  pass with DSS-16 the FOT asked the station to 
swap from TCP1 to TCP2.  After swapping TCPs, the corrections 
ceased.  IMPACT: None

DOY 04221 (08/08/04) ACE Anomaly G04-0092 - ROBOTT - C&C Paused Commanding
At 13:41:33, telemetry paused for a few seconds and then resumed.  However, 
C&C paused commanding and never resumed.  IMPACT:  Procedure 
S_OPS_PLBK_COMPLETE was not performed.  SSR Failover was not enabled. 
Procedure G_END_DAY was not performed.  AOS Timetag bins were not loaded 
which resulted in a low rate acquisition on next day's pass.

DOY 04222 (08/09/04) ACE Anomaly G04-0093 - ROBOTT - C&C Did Not Resume
Soon after g_initial_contact started, a telemetry drop occurred which 
paused C&C. Telemetry was back online in the same second, but C&C did not 
resume itself. FOT intervention was needed to resume C&C, but the procedure 
did not continue. C&C never issued the "go" directive at the hard wait. FOT 
intervention was needed again to enter a "go". IMPACT:  Without FOT 
intervention, the system would have been "Paused" for the entire pass. This 
is similar to other known problems and DR CDSID 21024 and 20995 were 
already open for this.

DOY 04223 (08/10/04) ACE Anomaly G04-0094 - ROBOTT - C&C Froze Due to 
TimeOutCC Rule
The FOT attempted a test to see what would happen if C&C tried to add CC 
privileges when ac1xt3 had the privileges. Once C&C detected that CC 
privileges failed to be added, the TimeOutCC rule started firing on and 
off. This cause a loop in this rule and the whole C&C system froze. The 
test was done after all commanding had completed, but the FOT had to run 
g_acedown manually.

DOY 04223 (08/10/04) ACE Anomaly G04-0095 - GDS 34m (DSS-24) APC Interface Lost
DSS-24 lost the interface to the Antenna Pointing Controller (APC). This 
caused a 50 minute telemetry outage and 62 minutes of command 
loss.  IMPACT:  Delayed pass activities, loss of command capability.   DR# 
G104698

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Glen A. Miller
ACE Flight Operations Observatory Engineer
Honeywell Technology Solutions Inc.
Goddard Space Flight Center
Building 14, Room W10A
Mail Stop 428.2
Greenbelt, MD 20771

Office: 301-286-7071
Pager: 800-425-3174
Fax:    301-286-1729
gamiller@pop500.gsfc.nasa.gov
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~