Instrument Health and Safety Checks - Normal Operations
PHASE: Operations SUBSYSTEM: Instrument
STATUS:
Criticality: Routine
Frequency: every pass
Duration(Approx.): 1 minute
Constraints: none
Procedure Description:
This procedure describes routine health and safety checks that should be performed by the Spacecraft Analyst each pass. The TRACE instrument is considered safe in the fact that it does not have dangerous high voltages or expendable gases or cryogenics. If TRACE were to have a failure of some sort it would likely be related to a number of moving parts, a computer failure or CCD damage. A number of safing RTS’s have been developed and are explained in the TRACE Contingency Document as well as a few other critical conditions that will be mentioned here. Analysts should fully understand instrument contingencies. S/C event messages will likely be the first indication of a problem while more subtle anomalies will be discovered by examining currents, voltages, and temperatures. Software anomalies will likely be uncovered through analysis by the EOF Team.
As always, notify EOF personnel in the event of a spacecraft safing event or other anomaly that warrants immediate attention.
Refer to
http://www.lmsal.com/TRACE/TRACElinks.html for information on many of the below discussed topics.
Health and Safety Checks
S/C Events
All Instrument related events are considered anomalous. Refer to the TRACE Contingency Document
Action Point Status - page ‘instsafe’
The instrument action points are explained in the TRACE Contingency Document. Many of the below AP’s that are disabled are chained action sequences that are enabled by the prior one.
|
Action Point # |
Status |
|
17-21, 24, 25, 27, 29, 31-34, 41, 42, 43 |
ACTIVE |
|
22, 23, 26, 28, 30, 40 |
DISABLED |
Nominal Status, Currents and Voltages - page ‘inst_power’
|
Component |
State |
Current |
|
DPU |
ON |
~1.0 A w/ peaks to 2.4 A |
|
Inst Ops Htrs |
ON |
0.6 to 2.5 A |
|
Inst Survival Htrs |
ON |
0.0 A |
|
Inst Bypass Htrs |
OFF |
0.0 A |
|
CCD Decontam Htrs |
OFF |
0.0 A |
|
Wax Act Pwr |
OFF |
0.0 A |
|
App. Elec. +5 V |
4.5 - 5.5 V |
|
|
App. Elec. +15 V |
14.5 to 15.5 V |
|
|
App. Elec. - 15 V |
-15.5 to -14.5 V |
|
|
Guide Telescope |
ON |
69 - 72 V |
|
Mechanisms |
ON |
0.0 with spikes to 2.0 A |
|
Mech. +15 V |
14.5 to 15.5 |
|
|
CCD Camera |
ON |
|
|
Camera +5 V |
4.5 to 5.5 |
|
|
Camera +15 V |
14.5 to 15.5 |
|
|
Camera -15 |
-15.5 to -14.5 |
|
|
Camera +30 |
29.0 to 31.0 |
Instrument Heater Status and Temperatures - page ‘inst_thermal’
The below numbers are initial L&EO numbers. Final numbers will be established once on orbit. The critical parameter is the CCD temperature which should never rise above 40 degrees. At times the CCD will undergo a ‘bake-out’ period in which either the decontamination or operational heaters will be used to raise the CCD temp to TBD degrees. This will probably be done by timeline commands however the FOT will be notified in advance. Most thermal safing actions are set to 45 ° C.
Verification Table - see ‘inst_thermal’ page
|
Zone |
Status |
Deadband H/L |
Duty Cycle |
Temp ° C |
|
1 Front A |
on |
83/94 |
3 |
10 - 14 |
|
2 Front B |
on |
73/94 |
4 |
10 - 14 |
|
3 Front C |
on |
73/94 |
3 |
10 - 14 |
|
4 Mid |
on |
73/94 |
2 |
10 - 14 |
|
5 Aft |
on |
73/94 |
2 |
10 - 14 |
|
6 GT |
on |
73/94 |
2 |
10 - 14 |
|
7 (CCD) |
off |
181/191 |
4 |
-15 - 20 |
Software Checks - page ‘dpu_sequence’
Many of the software problems will be discovered by the EOF team, however below are a few things of interest to watch.
|
CC S/W Ver/Patch |
1:34 |
|
DHC Firm Ver/Patch |
26:05 as of launch |
|
DHC Que Ver/Patch |
1:2C |
|
Sequence Status |
0x8000 - running 0x0000 - stopped 0x8800 - paused 0x0800 - paused |
|
DHC Status |
0x48 - running |
|
DHC Err Status |
0x3800 - no errors and not processing data; will change while processing |
|
CC Mode |
0 normal picture taking |
|
No Valid Cmd |
0 does not increment |
|
Clock |
incrementing |
Contingencies and Responses:
Refer to the TRACE Contingency Document