ACE Weekly 03/07/03 - 03/13/03

All ACE spacecraft subsystems are performing nominally. Attitude maneuvers 
were performed on 03/07/03 and 03/12/03 successfully. The next attitude 
maneuver is scheduled for 03/21/03.

============================================================================
Orbit Event:

SEV Transit
On 03/06/03, at 1754Z, ACE began a Solar Exclusion Zone (SEV) transit that 
will conclude on 03/20/03 at 1518Z. The minimum SEZ angle of 2.68 degrees 
will occur on 03/15/03 at 2326Z.

NOTE: Be advised that telemetry dropouts may occur during this time period.

The next expected SEV transit is to occur:

Entry: 06/01/03 at 1442Z
Minimum angle: 2.18 degrees on 06/13/03 at 1618Z
Exit: 06/25/03 at 1652Z

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

NONE

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

TAPS:
Trending, Analysis and Plotting System (TAPS) development continues with 
emphasis being placed on fixing the DRs attributed to the current release. 
TAPS Patch 4.1.1 was installed on TAPS #2 on 02/27/03. Testing is 
progressing on TAPS#2. TAPS#1 is no longer required for development and 
will be under CM control after the system has been wiped by the TSMs.  TAPS 
4.1.1 will be installed on TAPS#1 and released for testing.

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

Moving of the Offline subsystem has been delayed pending approval of 
updated offline activities and testing of those activities. The release of 
the Command & Control subsystem has been delayed until completion of 
WIND/POLAR automation task, new release date is TBD.

HSM is currently being tested by the FOT on string 3. HSM has been working 
well except for a few random problems that need to be addressed. It will go 
through several iterations before being moved to string 2. Once any piece 
of the ROBOTT software is moved to string 2, it will referred to as an 
'engineering' version and any problems will be documented via CDS.

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

DOY 03068 (3/9/2003) - ACE Anomaly Report G03-0011 - Command not received 
by Spacecraft
At 13:33, the FOT started the procedure C_SCIENCE.  At 13:34:56, the 
procedure was still waiting verification.  A check of the FOT command count 
indicated that 11 commands had been sent (10 cmd blks/1 test blk), and only 
10 echos rec'd.  At 13:37, the FOT contacted D54 to inquire about the 
command.  D54 informed the FOT that a total of 10 commands (9 cmd blks/1 
test blk) had been rec'd.  At 13:39, the FOT informed IP NOCC of  the 
situation.  IP NOCC had a command count of 11.  At the FOT's request, IP 
NOCC set their displays to monitor the next command from ACE.  At 13:52, 
the FOT informed JPL.  JPL stated they were unable to check for previous 
commands, however, they would stand-by to monitor the next real-time 
command.  At 14:06, the procedure, C_SCIENCE was terminated(kp-kill 
procedure) and a /resync was performed in order to sync the ground and 
spacecraft command counters.  At 14:09, after coordinating the next command 
with IP NOCC, JPL, and D54, the procedure C_SCIENCE was started again and 
verification was received.  All parties involved confirmed receiving the 
command.  After the pass a command delog was performed, however, there were 
no problems noticed with the command.  IMPACT: Minimal. Delayed the 
execution of C_SCIENCE and ULEIS_MOTOR_ERROR procedures.

DOY 03071 (3/12/2003) - ACE Anomaly Report G03-0012 - SEZ - Data loss at 
87648bps
Initial evidence indicates that we have reached the SEV angle (3.03deg) 
where 26m antennas are unable to maintain data at the high date rate.
~20% data loss at 15:00:00
~75% data loss at 17:30:00

Note:  At High-Rate, VC1 data also lost.  Unable to maintain continuous 
state of health check.  Therefore, SSR dump was not continued (even though 
it did capture some 6% of VC4 data).

ACTIONS:
15:00:00  At hi-rate --- data loss ~20%
15:29:42  Switched to RTSW (498bps) --- No data loss at 498bps
15:42:01  Switched to ADC (7968bps) --- No data loss at 7968bps
17:28:14  Switched back to hi-rate (87648bps) --- data loss ~75%.
17:45:36  Switched back to med-rate (7968bps).  No data loss.

Continued at Medium-Rate.  Scheduled a 2nd pass with D46 to do an attitude 
maneuver to ensure that HGA constraint would not violate if telemetry were 
lost before the next scheduled maneuver (originally scheduled for Friday).

IMPACT:  Unable to complete dump SSR B.

DATA LOSS (Preliminary Analysis):
Due to the inability to receive hi-rate data with DSS-16 on DOY 071 and the 
limited time with DSS-27 on DOY 072, the FOT was unable to complete the 
playback for DOY 070 and 071.  However, the FOT was able to focus on data
recorded between supports to reduce data loss.  Some of the gap is filled 
with real-time data, of which some is ADC. ADC contains the data for MAG, 
EPAM, CRIS, SIS and SWEPAM-I, but not SWEPAM-E, SWICS, SWIMS, SEPICA and ULEIS.

Totals over DOY 070 and 071:

Only ADC      2hr 02min 35sec
NO DATA     7hr 39min 42sec

The rest of the time captured either Science (vc1 or vc4) or BinDump 
(vc1).  (Note, BinDump contains all instrument data.)

Here are the time ranges:
070 15:14:20 - 15:31:13   only adc  16min 54sec
070 17:52:18 - 18:15:09   only adc  22min 52sec
070 18:15:10 - 18:17:57   no data     2min 48sec
071 08:07:58 - 14:56:37   no data     6hr 48min 40sec
071 14:56:38 - 15:30:06   some adc 17% captured (5min 20sec data/28min 
09sec lost)
071 15:30:07 - 15:43:23   no data/rtsw    13min 17sec
071 15:43:24 - 15:59:59   only adc           16min 36sec
071 16:00:00 - 16:06:47   no data/rtsw      6min 48sec
071 16:06:48 - 17:27:40   only adc            1hr 20min 53sec

Able to maintain hi-rate data on Days 072 through 075 using D27, D24 & D54 
(all 34m antennas).


DOY 03071 (3/12/2003) - ACE Anomaly Report G03-0013 - DSN GDS(DSS-16) - 
Antenna Track Stop
At 17:08:37 lost uplink.   Queried station DSS-16 as to the cause of the 
loss and DSS-16 reported the antenna had stopped tracking.  CAUSE:  While 
performing E-Stop PMs on DSS 15's antenna, the operator
pressed the wrong E-Stop button causing the DSS 16 antenna to go to 
brake.  Corrective Action:  The Axis Hydraulics were enabled, the 
transmitter beam was brought back up for ACE support and the track 
directive was entered. (Personnel Error)   IMPACT:  Telemetry loss between 
17:12:15 and 17:15:45  DR# M101446.




~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Glen A. Miller
Honeywell Technology Solutions Inc.

ACE Flight Operations Team
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
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~