Trigger 30 Description
Sequence: C2 (Antenna Deployment)
Trigger 30 (Modified Listen Mode with direction finding)
This mode is part of the antenna deployment checkout and is designed to
measure the electromagnetic noise environment of the instrument and spacecraft.
It runs internal to the instrument, and both Trigger 10 and Trigger 20 internally
go to this mode after completing the checkout portion of their trigger.
The HFR is in a free-run mode with direction finding, and LFR, MFR,
WBR, WFR, and LP data are collected during this trigger. The WFR and WBR toggle
between their Low- and High-frequency bands every 10 minutes, and the MFR toggles
between the EX and BX antenna every 32 seconds.
During the initial inflight use of Trigger 10, 20, and 30 (during the
antenna deployment in C2), the HFR did NOT go into the expected mode due
to a software feature between the HFR and the order that the HFR commands
were issued from the onboard sequence and the IEB (see ISA Z44412 for a
discussion of this issue and the solutions implemented to prevent this from
occurring in future sequences.
This problem only occurred during the antenna deployment sequence, and not
when the Triggers were sent individually. Comments have been added to the
C2 timeline to note which periods had Triggers that did not operate as expected.
The primary affect of this problem was that Trigger 30 did NOT put the
HFR in the expected mode at the end of Trigger 10 and 20 (the HFR stayed,
or entered its default mode).
Furthermore, for the first two uses of Trigger 20 (1997-298T00:15 and 03:38),
the HFR collected no data during the internal Antenna checkout part of the trigger,
resulting in no HFR data for about five minutes.
| Receiver |
Frequency Range |
Sensors |
Cycle Time |
| LFR |
1 - 25 Hz |
EX, BX
|
16 seconds |
| MFR |
0.025 - 12 kHz |
EX, BX
|
32 seconds |
| WFR |
1 - 40 Hz / 0.1 - 2.5 kHz
|
EX+, EX-, LP, BY, BZ |
25 seconds |
WBR
|
0.1 - 10.5 kHz / 0.1 - 80 kHz
|
EX
|
8 seconds
|
| HFR |
3.6 KHz - 16 MHz |
EX, EW
|
11 seconds |
LP
|
N/A
|
Langmuir Probe
|
16 seconds
|
The HFR is in the following mode.
This mode is defined by:
Correlations Channels Integ. Size Frequency
Band Ant. Auto- Cross- per Band df Period Rep Steps kHz Start - Stop
---- ---- ----- ------ -------- -- ------ --- ----- ---- ------------
ABC 2E y y 32 y 250 1 3.6-319 kHz
H1 2E y y 4 y 40 1 36 25 325k-1.200MHz
H2 1E n n 1 n 20 1 300 50 1.225M-16.175MHz
Bands ABC require 1.66 sec to complete, H1 requires 3.26 sec, and H2 requires 6.09 sec
for a total of about 11.12 sec per sweep.
During the periods when Trigger 30 did not operate properly (see the C2 timeline), the
HFR was in the following 'default' mode:
Correlations Channels Integ. Size Frequency
Band Ant. Auto- Cross- per Band df Period Rep Steps kHz Start - Stop
---- ---- ----- ------ -------- -- ------ --- ----- ---- ------------
ABC 2E y y 32 n 1000 1 3.6-319 kHz
H1 2E y y 4 n 160 1 70 25 250k-1.975MHz
H2 2E y y 1 n 80 1 70 200 2.025M-15.825MHz
Bands ABC require 3.12 sec to complete, H1 requires 12.30 sec, and H2 requires 6.27 sec
for a total of about 21.7 sec per sweep. However, the time between analyses is set to 24
seconds.