CAPS Checkout Report for 1999 DOY 006
from the desk of CAPS PI: Dave Young
During the off-pass period ELS and IBS continued to operate nominally. The
actuator (ACT) was left operating at +/- 40 degrees of actuation. Although
the ACT data product indicates unplanned rotational motions, other evidence
suggests that the data are corrupted to some extent, possibly by the
timing/synchronization anomaly that is occurring within the CPU2. The IMS
TOF high voltages held steady during off-pass at +/- 9 kV.
The plan for DOY checkout was to turn off IBS, ELS, and ACT before
proceeding to bring up the IMS TOF high voltages to their full operating
levels of +/- 14.6 kV. During the shutdown of the ELS sensor the IMS TOF
positive supply was inadvertently turned off. In order to maintain IMS
safety we commanded the negative supply off as well with about a 15 minute
delay. Investigation of the IMS HV off command indicated that the CAPS ECR
with new commands for checkout included 3 new detector threshold commands
for the 3 sensors. An error was found in the ECR and corrections were
communicated to JPL. Unfortunately the corrections were not implemented at
JPL so all 3 commands contained op code errors-one of which shut down the
IMS TOF positive HV supply.
After checks of the CAPS state of health, the DOY 005 procedure to turn on
the TOF supplies to +/- 9 kV was executed again successfully. The remainder
of the procedure was then executed, bringing the IMS TOF up to its full
operating voltage followed by the IMS detectors and ESA supplies. Detector
background counts remained low with all IMS HV supplies operating,
indicating excellent state of health of the sensor. The IBS and ELS sensors
and ACT were then turned on near the end of the pass. At this point (1540
UTC) CAPS was declared fully operational and was left on in this state at
the end of the pass.
Data quality and command response remained uniformly good throughout the
activities. Our thanks to the JPL team for their support and professiona
lism throughout this phase of CAPS ICO (more details and names when my
brain unsnarls from the late night jet lag).