ACE Weekly Report (05/17/02  05/23/02)

All ACE spacecraft subsystems are performing nominally. An attitude 
maneuver was successfully performed on 05/17/02.  The next attitude 
maneuver is scheduled for 05/28/02.

An engineering test is in progress to determine a new HGA constraint. The 
current constraint is 5.5 degrees, however the FOT has been given 
authorization to drift to as much as 6.0 degrees prior to maneuvers. The 
constraint was increased on 26 April, as part of a several step process 
that will occur over the next two months with the maximum constraint being 
reached by late June, when the spacecraft will be at its maximum 
range.  This approach allows the spacecraft to drift until the new 
constraint is violated, at which time an attitude maneuver is executed.

Date: HGA angle reached prior to Attitude Maneuver (degrees):

03/28/02 ~4.8
04/04/02 ~4.8
04/11/01 ~5.1
04/18/02 ~5.2
04/26/02 ~5.6
05/06/02 ~5.8
05/17/02 ~5.9

Analysis is ongoing, though no degradation in signal strength has been seen.

Anomalies:
05/18/02 DOY 138 - ACE Anomaly #G02-0059  Router went bad at JPL and was 
replaced. All data was recovered. (DR #N100430)

05/22/02 DOY 142  ACE Anomaly #G02-0060   Monitor block data was offline 
from 14:58:46 - 15:16:33.  A reboot of the SCP was required to bring data 
back online.  As a result of the SCP reboot, real-time data was offline 
from 15:15:29 - 15:16:30. All data was recovered.

05/23/02 DOY 143  ACE Anomaly #S02-0013   The mnemonic SSDLUCNT, which is 
the S3DPU Latch-up Counter, violated the science configuration monitor with 
a value of 1.  This mnemonic has been violating since DOY 137.  Mark 
Popecki was notified and informed the FOT that none of the Science data had 
been impacted, but he is going to investigate the cause of the Latch-up.