ACE Weekly Report (04/05/02  04/11/02)

All ACE spacecraft subsystems are performing nominally.  An attitude
maneuver was successfully performed on 04/11/02.  A stationkeeping
maneuver was also successfully executed on 04/11/02.  The next attitude
maneuver is scheduled for 04/18/02.

SSR Bs 30 telemetry sections were scrolled through on 04/09/02 to
verify the number of SBEs and DBEs.  It continues to have zero DBEs and
SBEs.  SSR As 30 telemetry sections were scrolled through on 04/10/02.
No DBEs or new SBEs were detected; 15 SBEs were originally detected in
December 1999.

An engineering test is in progress to determine a new HGA constraint.
The current constraint is 4.5 degrees.  The constraint will be increased
in several steps, over the next three months with the maximum constraint
being reached by late June, when the spacecraft will be at its maximum
range.  The first and largest step will be an increase to 5.5 degrees.
The approach used will be to allow the spacecraft to drift until the new
constraint would be violated.  An attitude maneuver would then be
executed.

Date:  HGA reached prior to Attitude Maneuver (degrees):
03/28/02    ~4.8
04/04/02    ~4.8
04/11/01    ~5.1
04/18/02    ~5.5 (expected)

Analysis is ongoing, though no degradation in signal strength has been
seen.  FDF used ~3.7 degrees as the target for the 04/11/02 attitude
maneuver to ensure the spacecraft would drift to ~5.5 degrees prior to
the attitude maneuver on 04/18/02.

March 2002 Data Recovery is 99.973%

Anomalies:
04/08/02  DOY 098 AR# G02-0039 Station D27 contacted MOC ~11 minutes
prior to BOT to inform FOT that AOS would be delayed due to problems at
site.  Support temporarily transferred to Station D16 while D27 resolved
problems with its CMC.  AOS delayed a total of ~30 minutes.  Initial
contact activities performed on D16.  Station D27 available after ~10
additional minutes.  Activities transferred back to Station D27.  No
further problems experienced during the support (DR #G100976).

04/10/02  DOY 100 AR# G02-0040  Station D16 did not have monitor data
enabled to MOC.  JPLCOM and Station notified.  After investigation, D16
notified FOT that SCP had to be rebooted.  FOT accepted expected ~2
minute telemetry dropout.  SCP rebooted and monitor data online shortly
thereafter.  All affected SSR data was redumped (DR #G100989).