ACE Weekly 09/03/04 - 09/09/04
All ACE spacecraft subsystems are performing nominally. An attitude=20
maneuver was successfully executed on 09/03/04. The next attitude maneuver=
=20
is scheduled for 09/10/04.
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Orbit Events:
The ACE transit of the Solar Exclusion Zone (SEZ) continues through=20
09/11/04. The minimum Sun angular radius was 0.32 degrees (as seen from=20
Earth's center) on 08/30/04. Features of this transit are given in the=20
following table.
8/18 4.96 deg inbound
8/25 2.13 deg inbound
8/29 0.61 deg inbound
8/30 0.32 deg minimum SEZ angle this transit
8/31 0.41 deg outbound
9/05 2.30 deg outbound
9/11 4.78 deg outbound
Some preliminary data in regards to Signal-to-Noise Ratios (SNR) for=20
contacts with DSS-27 at
low (498 bps), medium (7968 bps) and high (87648 bps) downlink data rates:
DOY SEV angle 498 7968 87648
--- ---------- ---- ------ -------
241 1.03-1.00=B0 8.2
242 0.67-0.64=B0 4.1
243 0.35-0.32=B0 15.0 7.5 -2.5 (no data at hi-rate)
244 0.37-0.40=B0 17.8 13.0 2.8
245 0.67-0.70=B0 8.0
246 1.05-1.08=B0 9.5
From the last transit, we found that DSS-27 could get good lock with=20
SNR=3D0dB (noise as big as signal). Given this data and the data from the=
=20
last transit, it looks like the following is a good rule-of-thumb:
0.3=B0-0.5=B0 50-50 chance of getting hi-rate with 34m/D27
>0.5=B0 likely to get hi-rate with 34m/D27
0.5=B0-0.8=B0 50-50 chance of getting hi-rate with 26m
>0.8=B0 like to get hi-rate with 26m
We have been able to get acquire low and medium rate at any SEV angle=20
(Sun-Earth-Vehicle).
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OCRs Executed:
None
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Ongoing Activities:
TAPS:
- Installation of TAPS release 4.3 occurred on 07/20/04. FOT testing of=20
this release is ongoing.
-- Of the 6 DRs fixed in release 4.3, all have been verified.
-- Two (2) new DRs have been opened to date.
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Automation (ROBOTT):
- On 08/25/04, ROBOTT v0.8.1 was installed on String 1 (OCR GND-143).
-- Operations is being conducted in the "auto" mode with the FOT closely=
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monitoring and noting any discrepancies.
- Testing of v0.8.1 by the FOT will continue on String 2.
-- To date all DRs fixed in this release have been tested. One (1) DR
has failed and eight (8) new DRs have been written against v0.8.1.
- ROBOTT v0.9 is in development and is tentatively scheduled for delivery=20
to Strings 2 & 3 in the coming week.
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Extra Spacecraft Activities:
None
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Anomalies:
DOY 04250 (09/06/04) ACE Anomaly G04-0103 - ROBOTT Failed To Run Script=20
FOT_RUN_ADS
The FOT configured C&C to run the script FOT_RUN_ADS before BOT=20
occurred. After the procedure G_INITIAL_CONTACT was ran C&C failed to=20
execute the script FOT_RUN_ADS. IMPACT: FOT had to initiate a block=20
replay and execute the script FOT_RUN_ADS manually. DR CDSID# 00021051
DOY 04252 (09/08/04) ACE Anomaly G04-0088 (Appended) - ADS Failure
Received error when attempting to start ADS. Killed processes on=20
workstation and rebooted the software. IMPACT: No impact to FDF.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Glen A. Miller
ACE Flight Operations Observatory Engineer
Honeywell Technology Solutions Inc.
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
gamiller@pop500.gsfc.nasa.gov
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