ACE Weekly Report:  06-28-00

All ACE spacecraft subsystems are performing nominally. An Attitude 
maneuver was successfully executed on 06-23-00.  The next attitude 
maneuvers are scheduled for 06-30-00 and 07-07-00.  A stationkeeping 
maneuver is also scheduled for 06-30-00.

On 6-23-00 ACE suffered ~10 minute data loss due to problems with the 
fanouts at GSFC.  The IP NOCC rebooted the fanouts and the remainder 
of the support completed without any further problems.  All SSR data 
successfully recovered.   Telemetry dropout occurred after the 
maneuver had already completed (AR# G00-0026).

On 6-24-00 ACE commanding delayed ~30 minutes due to problems with 
Station D54's CPA.  The CPA was swapped twice as well as the LMC. 
Commanding proceeded without any interruptions.  All SSR data 
successfully captured prior to the scheduled EOT (DR# L04462).

On 06-25-00 ACE had a DSN 26m Automation test with Station D16.  A 
backup telemetry string
was configured with the legacy equipment, in the event of any 
problems with the automated system. The next DSN 26m Automation test 
is scheduled for TBD.

      Summary:
       Preliminary analysis shows that all objectives were met.
1. Verification and loading of ACE operational tables.
2. Verification of tracking and telemetry lock of the ACE s/c at BOT.
3. Verification of ranging using the 26 meter automation system (FDF 
will validate data  on Day 178)
4. Verification of proper processing of s/c telemetry data and its 
delivery to the ACE MOC.
5. S/C command verification along with command echo processing by the 
26 meter automation system.
6. Validation of  MCT monitor data and its delivery to ACE MOC.  The 
ACE project will perform off-line analysis of monitor blocks to 
extract parameter values used by the ACE project.  ACE believes that 
the monitor data values are being sent to ACE however , the block 
structure has been modified and ACE  display pages are not looking at 
the correct data pointers.
7. Familiarize project with 26m automation system.

Previous Discrepancies:
1. Invalid CLCW - Problem not observed during this test.
2. Raw Observation Clock File Corruption - Did not occur during this test.
Analysis being performed offline to determine cause of corruption on Day 167.
String "B" was used at D16 vice string "A" used on day 167.  String 
"B" has a upgraded software release to fix a SOHO Standard Format 
Data Unit (SFDU) problem (DBT_6106-OP-A VER-3.6A).   Problems 
experienced during day 167 test, may have been unique to the "A" 
string  s/w version. Further analysis must still be performed.


On 6-28-00 ACE sustained two anomalies during this support.
1. ACE sustained ~10 minute span of degraded telemetry due to 
problems with Station D66's ground receiver.  Station changed loop 
bandwidth and problem was then corrected (DR# L04481).
2. Station D66 reported command rejections at the CPA during a period 
when no commanding was being performed by ACE.  Station D66 used the 
source code of the rejected command to identify GOES as the source of 
the commands.  GOES contacted and confirmed that they had 
inadvertently sent commands during a simulation (DR# L04482).

================================================
Jacqueline Maldonado Snell
Honeywell Technology Solutions Incorporated (HTSI)
Goddard Space Flight Center
Bldg. 3 Rm N135C, Code 428.2
Greenbelt, MD 20771
Phone: (301) 286-7072
Fax:   (301) 286-0218
E-mail:   Jacqueline.Snell.1@gsfc.nasa.gov