 |
WSDC IOC and Early Operations Check-Out Activities |
 |
| Category | Activity | Cover On | Cover Off | Notes |
|---|
| Mission Operations Support | Data flow tests | X | | |
| | Aliveness test | | X | TBD |
| | Scan rate/scan mirror synchronization | | X | |
| | ADCS/Boresight offset measurement | | X | |
| | SAA and moon proximity testing | X | X | |
| | Anneal performance testing | | X | |
| Science Pipeline Initialization and Parameter Tuning | Instrumental characterization and calibration data updates | | X | |
| | Boresight offset calibration and band-to-band offset measurement | | X | |
| | Image artifact mapping and characterization | | X | |
| | Aperture curve of growth (or PSF) mapping and stability check | | X | |
| | Photometric zero point determination (throughput testing)
| | X | |
I. Cover-On Activities (IOC Weeks 1-2)
1. Data flow/ingest test
1.1 Receive cover-on science data from ground station. Ingest and construct
FITS frames.
1.2 Receive and ingest H/K telemetry. Update raw image FITS headers.
1.3 Receive and ingest Orbital Events File
1.4 Receive and ingest SPICE kernels
1.5 Generate science data, H/K, orbital events, metadata tables and load
metadata databases.
1.6 Update Science FITS image headers with appropriate metadata
1.7 Test staging for processing.
1.8 Test feedback system to MOS and Science Planning.
2. Detector characterization update
2.1 Update W1 and W2 calibration dark frames if cover is dark enough
in bands 1 and 2. W3 and W4 will be saturated.
2.2 Generate statistics and noise test for W1 and W2 raw image frames.
2.3 Search for new transient (hot) pixels in W1 and W2 detectors and
update ground hot pixel masks.
3. SAA Proximity Testing
3.1 Generate charged particle detection count statistics for "dark" W1
and W2 frames.
3.2 Test SAA proximity limits by noting cover-on charged particle detection
rate as a function of proximity to SAA (W1 and W2 only).
II. Cover-Off Activities (IOC Weeks 3-4 and Ops Weeks 1-4)
1. Scan rate/scan mirror synchronization measurement and feedback to SOC
1.1 Scan rate and angle
1.1.1 Measure mean image second moment ratios and position angles for
set of exposures taken at assorted scan rates.
1.1.2 Generate moment ratio and angle vs. scan rate setting diagrams and
post in web-accessible QA reports.
1.2 Derive QA warning thresholds for image symmetry deviation
2. Focal-plane boresight calibration
2.1 ADCS-Boresight offset, rotation
2.1.1 Compare instrumental coordinate system with reconstructed
astrometric coordinate system of extracted sources
2.2 Band-band offsets, rotations
2.2.1 Measure relative instrumental positions of the same objects
between bands.
2.3 Determine plate scales
2.4 Distortion mapping
2.4.1 Use source cross-stepping derived from exposures near the
ecliptic poles.
3. Detector instrumental calibration baselines and updates
3.1 Responsivity image update
3.1.1 Low frequency update using source cross-stepping from exposures
near the ecliptic poles.
3.2 Low response pixel update
3.2.1 Identify low response pixel mask from responsivity test
(using zody background?) and update image masks.
3.3 Hot pixel identification and mask using source count distributions
3.4 Linearity (can this be tested on-orbit?)
3.5 Si:As detector droop test (can this be tested on-orbit?)
4. Photometric calibration initialization
4.1 Measure initial instrumental photometric zero points
4.1.1 Identify and measure standard stars near ecliptic poles.
Determine usability.
4.1.2 Compute mean and RMS of differences between instrumental and
"true" magnitudes.
4.1.3 Determine color-terms, if necessary.
4.2 Bootstrap calibration to secondary standards detected in ecliptic
pole fields.
4.3 Monitor zero point stability over multiple orbits
4.4 Monitor photometric stability orbit-to-orbit using scan overlaps
4.5 System throughput measurements
5. Source detection initialization
5.1 Set source detection thresholds
5.1.1 Measure noise distributions of high-pass-filtered images
5.1.2 Determine optimal SNR thresholds for detection to meet
completeness requirements
6. Photometric measurement initialization
6.1 Measure point source multi-aperture curve-of-growth as function of
focal plane position using extracted source lists
6.2 Construct psf and variance focal plane maps, if psf-fit photometry
is adopted
7. Bright source artifact mapping
7.1 Latent images
7.1.1 Measure decay curve for bright source latent image using extracted
source tables.
7.1.2 Determine if dark latents impact detector responsivity. If so,
derive correction.
7.2 Determine if detector "droop" is an issue for Si:As detectors
(Can this be done on-orbit?)
7.3 Diffraction spikes
7.3.1 Map geometry of diffractions spikes as a function of parent star
brightness using images and extracted source tables
7.4 Dichroic glints
7.4.1 Map geometry of dichroic glints as a function of parent star
brightness using images and extracted source tables
7.5 Electronic ghosts
7.5.1 Map geometry of electronic ghost features as a function of parent
star brightness using images and extracted source tables
7.6 Optical ghosts
7.6.1 Map geometry of optical ghost features as a function of parent star
brightness using images and extracted source tables
8. Anneal Characterization
8.1 Time to stability
8.1.1 Measure image statistics (e.g. noise, bg) as a function of time
following anneal
8.2 Latent image
8.2.1 Repeat image artifact tests (II.7.1) following anneal cycle
and compare latent amplitude and image decay profiles
9. Moon and SAA avoidance limits
9.1 Background levels
9.1.1 Measure mean backgrounds as a function of moon angle and estimate
impact on sensitivity and completeness. Determine practical limit
for processing data taken near moon.
9.2 Charged particles
9.2.1 Measure charged particle impact rate as a function of distance
from nominal SAA boundaries. Determine practical limit for
processing data taken near SAA.
Last update - 23 January 2007
R. Cutri - IPAC