Cold time is defined as any temperature reading <= -117.2 degrees C.
NOTE: Cold Temperature Limit value changed as of the April 12, 2021 run.
We are operating on 12 month calibration periods, starting on DOY 032.
The present calibration period begins at: 2023:001:13:30:52.830 and today is: 2023:009:13:20:55.573 .
It is important to note that the target exposure times listed below will increase by a factor
of 12% every 6 months epoch due to the half-life of the calibration source.
II. Statistics Since the Start of the Current Epoch
Cold Time Statistics:
| Chip | Required (seconds) | Achieved (seconds) |
|---|---|---|
| I0 | 140000.0 | 103071.3 |
| I1 | 140000.0 | 275732.1 |
| I2 | 140000.0 | 243804.7 |
| I3 | 140000.0 | 243804.7 |
| S0 | 70000.0 | 22344.2 |
| S1 | 90000.0 | 81774.4 |
| S2 | 140000.0 | 97363.3 |
| S3 | 180000.0 | 298076.3 |
| S4 | 70000.0 | 54271.6 |
| S5 | 70000.0 | 22344.2 |
| Recovered Science Time (seconds): | 274098.0 |
|---|
| SI Mode | Total Number of Obs. | Total Exposure Time (sec) | Average Exposure (sec/obs) | Primary 6 Chip SI Modes | TE_007AC | 63 | 338618.8 | 7057.7 |
|---|---|---|---|
| TE_007AE | 53 | 304023.40 | 7443.92 |
| TE_00B26 | 57 | 305911.20 | 7072.63 | Old 6 Chip SI Modes | TE_00216 | 0 | 0.00 | 0.00 |
| TE_0021C | 0 | 0.00 | 0.00 |
| TE_008EA | 0 | 0.00 | 0.00 | 5 Chip SI Modes | TE_00C60 | 8 | 50707.80 | 7906.87 |
| TE_00CA8 | 4 | 16786.40 | 5765.00 | 4 Chip SI Modes | TE_00C62 | 3 | 320737.07 | 108340.96 | Totals: | 195 | 1391583.3 |
Rule #1: The key time period for balancing SI mode statistics is the 6 month Epoch
By the end of the epoch, the SI mode statistics should match the rules stated below.
Rule #2: Each of the three, default, 6 chip, SI modes (or their 5 chip equivalents) must be used
at least once in each load week.
- If two SI modes are lagging in either cold time or total time, apportion the week's ECS
measurements between the two of them roughly commensurate with the amount they are lagging.
- The 6 month Epoch allows "even" correction of two lagging SI modes. No
need to pile a weeks worth of ECS measurements on one SI mode if two are lagging.
Rule #3: Make certain to spread the amount of COLD ECS time as evenly as possible across all three SI modes
Balance Cold measurement data between the three default 6-chip modes within 10%
of each other on an Epoch basis
Rule #4: Spread the amount of *Total* ECS time as evenly as possible across all three SI modes.
- Balance Total measurement data between the three default 6-chip modes within 10%
of each other on an Epoch basis.
Rule #3 takes precedence over Rule #4.
Rule #5: At least 60% of scheduled ECS measurement time must be -119.2 deg. C
Rule #6: Any ECS measurements during a Perigee Passage that are cold MUST be assigned to the nominal
ECS SI modes. i.e. Any requested Rawmode runs can be done with a warm focal plane.
Presently, the only 6 chip SI modes used during Perigee Passages are:
A word about the COLD Time stats:
Cold Time is defiined by focal plane temperatures <= -117.2 degrees C.
Guidance for SI Mode Mapping between 6, 5 and 4 chip modes:
The 6 chip SI Mode set consist of five modes. But there are only two, 5 chip SI Modes and only three, 4 chip SI modes. So there is not a one to one mapping of 6 to 5 to 4 chips with unique modes. Here is the chip-drop rule set as presently defined:
6 chip 5 chip 4 chip
TE_007AC -> TE_00C60 -> TE_00D78
TE_00B26 -> TE_00C60 -> TE_00D78
TE_007AE -> TE_00CA8 -> TE_00D78
TE_00D7C -> TBD
TE_00D7E -> TBD
1) TE_007AC
2) TE_00B26
3) TE_007AESI Mode to Chip Mappings:
6 Chip SI Modes
TE_007AC - I0-I3 + S2-S3
TE_00B26 - I0-I3 + S1,S3
TE_007AE - S0-S5
TE_00D7C - I0-I1 + S1-S4
TE_00D7E - I2-I3 + S1-S4
5 Chip SI Modes
TE_00C60 - I0-I3 + S3
TE_00CA8 - S1-S5
4 Chip SI Modes
TE_00C62 - I1-I3 + S3
TE_00D78 - I0-I3
TE_00D7A - S1-S4
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