ACE Weekly Report: 08-08-01

All ACE spacecraft subsystems are performing nominally.  An attitude maneuver
was performed on 08/07/01. The next attitude maneuver is scheduled 
for 08/10/01.

Instrument high voltage ramp up activities were performed following the
completion of Z-axis maneuver activities on 7/25/01.  SWEPAM-E and
SWEPAM-I completed their activities on 7/26/01.  SWICS and SWIMS
were returned to their nominal configuration on 7/27/01.

SEPICA was returned to operations on 07/31/01 after OCRs SEP-095 and
SEP-096 were executed on 07/30-31/01.   The instrument  "is generating
data for elemental fluxes and charge states.  The gas system is running
under automatic regulation at 14.5 torr.  At this pressure, the fill valve is
opened for only 320 mS at a time, which should minimize stress. The lifetime
of the valve is unknown, however."  Valves for fan one and two failed in
February and December 1998, leaving fan valve three (F3) as the sole
  functioning valve.

OCR ULEIS-035 was executed on 08-08-01 to disable autonomous shutter
  motion mode. The Instrument team began seeing anomalous shutter motion
errors in telemetry after the mode had been enabled on 07-23-01.  Further
analysis will be performed as part of an investigation.

Anomalies
7-25-01 AR# G01-0060 - Approximate 8 minute telemetry drop out due to
INIF in panic mode. The IP NOC was contacted and the software restarted.
Affected SSR slices were redumped.  No further problems experienced with
INIF during the support.

7/27-28/01  AR# G01-0061 -  The automation team had inadvertently left
  the ISIS software running on the third string on days DOY 208 and 209.
While the ISIS software can be run simultaneously on the ACE strings, only
one string can have command privileges at any one time.  Since the software
was running on the third string, the FOT was unable to attain command
privileges during prepass activities on Friday and Saturday, July 27th and
28th.   Once the problem was recognized, the FOT killed the software running
on the third string and were then able to get 'rank 0' and 
successfully transmit
commands to the DSN site.  The supports continued without any additional
problems.  The automation team has been notified of the incidents and have
altered their scripts to prevent a reoccurrence of this anomaly.  Additional
  precautions will be taken to prevent real time operations from being further
impacted.

08/01/01 AR# G01-0064 -  The MOC was unable to successfully transmit
commands to the S/C for approximately the first 20 minutes of the support,
due to problems with D27's CPA.  The CPA was swapped and no further
command problems were experienced during the support [DR# G100161].

08/01/01 AR# G01-0065 - The MOC experienced ~25 minute telemetry
dropout lost lock on the spacecraft.  Telemetry back online after the station
repointed the antenna [DR# G100162].

================================================
Jacqueline Maldonado Snell
Honeywell Technology Solutions Incorporated (HTSI)
Goddard Space Flight Center
Bldg. 14 Rm W10B, Code 428.2
Greenbelt, MD 20771
Phone: (301) 286-7072
Fax:   (301) 286-1729
E-mail:   Jacqueline.Snell.1@gsfc.nasa.gov