STScI Logo

Hubble Space Telescope
Phase I: COS/NUV MAMA Recovery after Anomalous Shutdown

COS Cycle-18 Calibration Phase-1

Last Revised:                  8/25/10 
Proposal ID:                   12430
Title:                         COS/NUV MAMA Recovery after Anomalous Shutdown
PI:                            T. Wheeler
Co-I(s):                       A. Welty

---------------------------------------------------------------------------
# Orbit estimates are TOTAL for all of cycle-18

Total Prime Orbits:            n/a
External Parallel Orbits:      n/a
Internals or no-impact orbits: n/a
Comments on orbit estimate:    This is a contingency proposal only.
---------------------------------------------------------------------------
# This section should be written with a GO audience in mind -- use 
# Calibration plans in WFPC-2 handbook as a guide.

Purpose: This proposal is designed to permit the safe and orderly recovery of the COS/NUV MAMA detector after an anomalous shutdown. This is accomplished by using slower-than-normal MCP and PC high-voltage ramp-ups and diagnostics.

Description: Anomalous shutdowns can occur because of bright object violations, which trigger the Global Hardware Monitor or the Global Software Monitor. Anomalous shutdowns can also occur because of MAMA hardware anomalies or failures. The cause of the shutdown should be thoroughly investigated and understood prior to recovery. Twenty-four hour wait intervals are required after each test for MCP gas desorption and data analysis. COS event flag 2 is used to prevent inadvertent MAMA usage.

The recovery procedure consists of three separate tests (i.e. visits) to check the MAMA’s health after an anomalous shutdown. Each must be successfully completed before proceeding onto the next. This proposal executes the same steps as cycle 17 proposal 11892.

 (1) Signal processing electronics check. This reduces amplifier thresholds
     to 0.28V and monitors the ORCOUNT rate. (MAMA HV is off during this
     procedure)
 (2) Slow, intermediate voltage HV ramp-up. The MCP and PC are slow-ramped 
     with plateaus to a MCP voltage 300V below nominal and a PC voltage of 
     -50V. A dark time-tag exposure is taken during this partial ramp. A 
     second time-tag dark exposure is taken where the event counter is cycled 
     through W, X, Y, Z, OR, EV and VE
 (3) Slow, full voltage HV ramp-up. The MCP and PC are slow-ramped with 
     plateaus to the full MCP and PC operating voltages. As before, a dark 
     time-tag exposure is taken during the ramp. A second dark time-tag 
     exposure is taken where the event counter is cycled through W, X, Y, Z, 
     OR, EV and VE. This is followed by and fold analysis test (See COS MAMA 
     Fold Distribution for details).

Accuracy:                      n/a 

Comments on Accuracy:          n/a

Products:                      n/a 

---------------------------------------------------------------------------
# Link to cycle 18 Science
# Use the GO + GTO Phase 1 exposure listing and derived statistics
# posted on WWW.

Fraction of science programs supported by this calibration: This is a contingency procedure only.

List categories of science which can't be executed until after this proposal:  
                               n/a
why:                           n/a

List categories of science which are best performed contemporaneous with this proposal:                      n/a
why:

---------------------------------------------------------------------------
# THE REST OF THIS FORM IS FOR INTERNAL USE
---------------------------------------------------------------------------
Observation summary: The recovery from an anomalous shutdown consists of three tests: a signal processing electronics check, high-voltage ramp-up to an intermediate voltage and a high-voltage ramp-up to the full operating voltage followed by a fold distribution test. During each of the two high voltage ramp-ups, time-tag exposures are taken and diagnostics are performed. Post-ramp dark time-tags with diagnostics are also taken. The final, full ramp is followed by a fold distribution test.

# Target information (copy for each target)

Target Name.                            : n/a
RA.                                     : n/a
Dec.                                    : n/a
Flux (and units).                       : n/a
Visibility window (if known or relevant): n/a
Comment on choice of target             : n/a

# Exposure list plan at the Phase I level. Be as complete as reasonable. 
# If possible information should be complete enough to allow easy 
# submission of a Phase 2 from this form. However, if you have to leave
# some of the fields blank below, or want to provide the information
# in another format, that is acceptable. (Make sure you do the BOP checking
# though, as this is a phase-1 issue.)

-------------------------------------------------------------------------
**** This list of exposures should be executed ONLY in the event of  ****
****               an anomalous COS/NUV MAMA shutdown                ****
-------------------------------------------------------------------------
Note (1)
Bright Object Protection Considerations during the Visit 3 and Visit 6.
(a)	This proposal uses aperture/grating/lamp combinations which are 
      designed to produce count rates of ~1,000-2,000 count/sec. They should 
      not be changed without consultation with the P.I.
  (b) During the execution of the fold analysis some anode folds are 
      disabled. Consequently, the OR counter does not provide a true 
      representation of the OR count and so the Software Global Monitor (SGM) 
      does not trigger until the enabled folds provide enough counts to the 
      OR counter to trigger the SGM's threshold. To compensate, while the 
      fold analysis is running the SGM threshold is reduced to 150,000 counts 
      (130,000 counts are used due to ground system restrictions) in a 1.0 
      second interval, from its nominal value of 77,000 counts in a 0.1 
      second interval.
  (c) For the reasons discussed in (b) and to prevent light from entering the 
      hub this test should only be run with the COS external shutter closed.

Note (2)
Voltage ramping terms and polarity terminology.
With the COS NUV MAMA detector, the term ramp-up means to make the MCP or PC more negative in applied voltage. Ramping down means heading towards 0V.

Table of exposures (copy for each exposure as appropriate/desired):

Visit 1, Exposure 1: Signal Processing Electronics Checkout - LV On
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : n/a
Central Wavelength                      : n/a
Exposure Time                           : 1005s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : n/a, no detector HV
BOP Predicted Global Count Rate for MAMA: n/a, no detector HV
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments:
    Same alignment Sequence 1-3.
    Switch on LV power supply.
    Set SGM Threshold = 10000, Integration Period = 0.1 secs.
    Set amplifier threshold to default (0.48V)- Collect a minimum of 30
      telemetry points.
    Set amplifier threshold to 0.28V- Collect a minimum of 30 telemetry 
      Points.
    Special commanding: Instruction = ELHDTLVN_1.

Visit 1, Exposure 2: Signal Processing Electronics Checkout - LV Off
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : n/a
Central Wavelength                      : n/a
Exposure Time                           : 30s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : n/a, no detector HV
BOP Predicted Global Count Rate for MAMA: n/a, no detector HV
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments:
    Special commanding: Instruction = RLLVTHDN.

Visit 1, Exposure 3: Signal Processing Electronics Checkout - Set Flag 2
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : n/a
Central Wavelength                      : n/a
Exposure Time                           : 1s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : n/a, no detector HV
BOP Predicted Global Count Rate for MAMA: n/a, no detector HV
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments:
    Special commanding: Instruction = ELFLAG2.

Visit 2, Exposure 1: Intermediate HV Checkout - LV On
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : n/a
Central Wavelength                      : n/a
Exposure Time                           : 60s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : Special monitoring per ISR 98-03
BOP Predicted Global Count Rate for MAMA: Special monitoring per ISR 98-03
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments:
    Sequence 1-6 Non-Int.
    Must clear event flag 2 for the commanding to execute.   
    Switch on LV power supply.
    Special commanding: Instruction = ELHDTLVN_2.

Visit 2, Exposure 2: Intermediate HV Checkout - Ramp HV to -1750V/-50V
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Time-Tag
Spectral Element                        : Default
Aperture                                : Default
Central Wavelength                      : n/a
Exposure Time                           : 1800s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : Special monitoring per ISR 98-03
BOP Predicted Global Count Rate for MAMA: Special monitoring per ISR 98-03
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Buffer Time = 2000
                                          Special commanding
Comments:
    The MCP and PC Voltage partial Ramp-ups will be performed in stages. The 
    ramp-up within a stage is by increments of -50V. The final MCP voltage 
    will be -1750V, 300V shy of the nominal value of -2050V. The final PC 
    Voltage will be -50V, rather than the nominal -800V setting. Use the 
    nominal yellow and red ramping limits. At the end of each stage, reset 
    the SGM to a Threshold = 100 and an Integration Period = 0.1 sec, and 
    collect telemetry samples of OR Counts for 4 minutes. The COS rate is 1 
    TLM sample/10 secs; ~24 samples will be obtained.
        Stage 1 - MCP ramp-up (0 to -500V)
        Stage 2 - MCP ramp-up (-500V to -1000V)
        Stage 3 - MCP ramp-up (-1000V to -1500V)
        Stage 4 - MCP ramp-up (-1500V to -1750V)
        Stage 5 - PC Voltage ramp-up (+20 to -50V)
    Special commanding: Instruction = ELHVPART2.

Visit 2, Exposure 3: Intermediate HV Checkout - Cycle SGM
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Time-Tag
Spectral Element                        : Default
Aperture                                : Default
Central Wavelength                      : n/a
Exposure Time                           : 570s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : Special monitoring per ISR 98-03
BOP Predicted Global Count Rate for MAMA: Special monitoring per ISR 98-03
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Buffer Time = 720
                                          Special commanding
Comments:
    Set SGM Threshold = 200, Integration Period = 0.1 secs.
    Collect minimum 5 samples W events.
    Collect minimum 5 samples X events.
    Collect minimum 5 samples Y events.
    Collect minimum 5 samples Z events.
    Collect minimum 5 samples OR events.
    Collect minimum 5 samples EV events.
    Collect minimum 5 samples VE events.
    Special commanding: Instruction = ELHVDARK2.

Visit 2, Exposure 4: Intermediate HV Checkout - HV Off
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : n/a
Central Wavelength                      : n/a
Exposure Time                           : 250s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : Special monitoring per ISR 98-03
BOP Predicted Global Count Rate for MAMA: Special monitoring per ISR 98-03
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments:
    Ramp down detector.
    Special commanding: Instruction = ELHVTLVN_2.

Visit 2, Exposure 5: Intermediate HV Checkout - LV Off
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : n/a
Central Wavelength                      : n/a
Exposure Time                           : 30s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : n/a
BOP Predicted Global Count Rate for MAMA: n/a
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments: 
    Turn LV off.
    Special commanding: Instruction = RLLVTHDN.

Visit 2, Exposure 6: Intermediate HV Checkout - Set Flag 2
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : n/a
Central Wavelength                      : n/a
Exposure Time                           : 1s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : n/a
BOP Predicted Global Count Rate for MAMA: n/a
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments:
    Set Flag 2.
    Special commanding: Instruction = ELFLAG2.

Visit 3, Exposure 1: Full High Voltage Test - LV On
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : n/a
Central Wavelength                      : n/a
Exposure Time                           : 60s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : n/a
BOP Predicted Global Count Rate for MAMA: n/a
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments:
    Sequence 1-6 Non-Int.
    Switch on LV power supply.
    Must clear event flag 2 for the commanding to execute.
    Special commanding: Instruction = ELHDTLVN_3.

Visit 3, Exposure 2: Full High Voltage Test - Ramp HV to -2050V/-800V
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Time-Tag
Spectral Element                        : Default
Aperture                                : Default
Central Wavelength                      : n/a
Exposure Time                           : 3090s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : Special monitoring per ISR 98-03
BOP Predicted Global Count Rate for MAMA: Special monitoring per ISR 98-03
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Buffer_Time = 3300
                                          Special commanding
Comments:
    Special NUV HV turn on & slow full ramp up. The MCP and Field Voltage 
    Ramp-ups will be performed in stages. The ramp-up within a stage is by 
    increments of 50V. Use the nominal yellow and red limits for ramping. At 
    the end of each stage, reset the SGM to a Threshold = 100 and an 
    Integration Period = 0.1 sec, and collect telemetry samples of OR Counts 
    for 4 minutes. The COS rate is 1 TLM sample/10 secs; ~24 samples will be 
    obtained.
        Stage 1 - MCP ramp-up (0 to -500V)
        Stage 2 - MCP ramp-up (-500V to -1000V)
        Stage 3 - MCP ramp-up (-1000V to -1500V)
        Stage 4 - MCP ramp-up (-1500V to -1750V)
        Stage 5 - PC Voltage ramp-up (+20 to -50V)
        Stage 6 - MCP ramp-up (-1750V to -1850V)
        Stage 7 - MCP ramp-up (-1850V to -1950V)
        Stage 8 - Final MCP ramp-up (-1950V to-2050V)
        Stage 9 - Final PC Voltage ramp-up (-50V to -800V)
    Special commanding: Instruction = ELHVPART3.

Visit 3, Exposure 3: Full High Voltage Test - Cycle SGM
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Time-Tag
Spectral Element                        : Default
Aperture                                : Default
Central Wavelength                      : n/a
Exposure Time                           : 450s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : Special monitoring per ISR 98-03
BOP Predicted Global Count Rate for MAMA: Special monitoring per ISR 98-03
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Buffer Time = 720
                                          Special commanding
Comments:
    Set SGM Threshold = 200, Integration Period = 0.1 secs
    Collect 5 samples W dark events
    Collect 5 samples X dark events
    Collect 5 samples Y dark events
    Collect 5 samples Z dark events
    Collect 5 samples OR dark events
    Collect 5 samples EV dark events
    Collect 5 samples VE dark events
    Special commanding: Instruction = ELHVDARK3.

Visit 3, Exposure 4: Intermediate HV Checkout - HV Off
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : None
Central Wavelength                      : n/a
Exposure Time                           : 355s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : Special monitoring per ISR 98-03
BOP Predicted Global Count Rate for MAMA: Special monitoring per ISR 98-03
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments: 
    Ramp down detector, HV off.
    Special commanding: Instruction = ELHVTLVN_3.

Visit 3, Exposure 5: Intermediate HV Checkout - LV Off
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : n/a
Central Wavelength                      : n/a
Exposure Time                           : 30s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : Special monitoring per ISR 98-03
BOP Predicted Global Count Rate for MAMA: Special monitoring per ISR 98-03
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments:
    Turn LV off.
    Special commanding: Instruction = RLLVTHDN.

Visit 3, Exposure 6: Intermediate HV Checkout - Set Flag 2
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : None
Central Wavelength                      : n/a
Exposure Time                           : 1s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : n/a
BOP Predicted Global Count Rate for MAMA: n/a
ETC PID IDs for Count Rates             : n/a
Special Requirements or options         : Special commanding
Comments:
    Set Flag 2.
    Special commanding: Instruction = ELFLAG2.

Visit 4, Exposure 1: Full High Voltage Test - Fold Test Setup
Target or lamp                          : Dark
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Data
Spectral Element                        : n/a
Aperture                                : n/a
Central Wavelength                      : n/a
Exposure Time                           : 20s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : Note (1)
BOP Predicted Global Count Rate for MAMA: Note (1)
ETC PID IDs for Count Rates             : 
Special Requirements or options         : Special Commanding
Comments:
    Sequence 1-2 Same-Alignment.
    Set SGM Threshold = 15000, Integration Period = 0.1secs.
    Special commanding: Instruction = ELFOLDSET.

Visit 4, Exposure 2: Full High Voltage Test - Fold Test
Target or lamp                          : D2- Medium
Type of Acquisition                     : n/a
Detector for observation                : COS/NUV
Operating mode                          : Time-Tag
Spectral Element                        : G185M
Aperture                                : FCA
Central Wavelength                      : 1850
Exposure Time                           : 2300s
Number of Iterations                    : 1
BOP Predicted Local Count Rate for MAMA : Note (1)
BOP Predicted Global Count Rate for MAMA: Note (1)
ETC PID IDs for Count Rates             : 
Special Requirements or options         : Buffer Time = 2300
                                          Special commanding
Comments:
    Set SGM Threshold = 100000, Integration Period = 1.0 secs
(a) Collect counter samples during flat field illumination
    Collect 60 sec W events
    Collect 60 sec X events
    Collect 60 sec Y events
    Collect 60 sec Z events
    Collect 60 sec OR events
    Collect 60 sec EV events
    Collect 60 sec VE events
(b) Disable MAMA Folds: C2, C3, C4, C5, C6, R2, R3, R4, R5, R6
(c) Conduct fold analysis
    Collect 60 sec VE for following 19 combinations of MAMA folds:
        (1) Enabled: C2, R2; Disabled: C3, C4, C5, C6, R3, R4, R5, R6
        (2) Enabled: C2, R3; Disabled: C3, C4, C5, C6, R2, R4, R5, R6
        (3) Enabled: C3, R2; Disabled: C2, C4, C5, C6, R3, R4, R5, R6
        (4) Enabled: C2, R4; Disabled: C3, C4, C5, C6, R2, R3, R5, R6
        (5) Enabled: C3, R3; Disabled: C2, C4, C5, C6, R2, R4, R5, R6
        (6) Enabled: C4, R2; Disabled: C2, C3, C5, C6, R3, R4, R5, R6
        (7) Enabled: C3, R4; Disabled: C2, C4, C5, C6, R2, R3, R5, R6
        (8) Enabled: C4, R3; Disabled: C2, C3, C5, C6, R2, R4, R5, R6
        (9) Enabled: C3, R5; Disabled: C2, C4, C5, C6, R2, R3, R4, R6
       (10) Enabled: C4, R4; Disabled: C2, C3, C5, C6, R2, R3, R5, R6
       (11) Enabled: C5, R3; Disabled: C2, C3, C4, C6, R2, R4, R5, R6
       (12) Enabled: C4, R5; Disabled: C2, C3, C5, C6, R2, R3, R4, R6
       (13) Enabled: C5, R4; Disabled: C2, C3, C4, C6, R2, R3, R5, R6
       (14) Enabled: C4, R6; Disabled: C2, C3, C5, C6, R2, R3, R4, R5
       (15) Enabled: C5, R5; Disabled: C2, C3, C4, C6, R2, R3, R4, R6
       (16) Enabled: C6, R4; Disabled: C2, C3, C4, C5, R2, R3, R5, R6
       (17) Enabled: C5, R6; Disabled: C2, C3, C4, C6, R2, R3, R4, R5
       (18) Enabled: C6, R5; Disabled: C2, C3, C4, C5, R2, R3, R4, R6
       (19) Enabled: C6, R6; Disabled: C2, C3, C4, C5, R2, R3, R4, R5
(d) Enable MAMA folds C2, C3, C4, C5, C6, R2, R3, R4, R5, R6
    at completion of exposure.
(e) Check lamp stability by checking EV and VE
    Collect 60 sec events (EV) to check lamp stability
    Collect 60 sec Valid Events (VE) to check lamp stability
(f) Turn off D2 lamp
(g) Collect event counter data for detector dark count rate
    Collect 60 sec W dark events
    Collect 60 sec X dark events
    Collect 60 sec Y dark events
    Collect 60 sec Z dark events
    Collect 60 sec OR dark events
    Collect 60 sec EV dark events
    Collect 60 sec VE dark events
(h) At completion of procedure reset SGM to nominal operating level
    Special commanding: Instruction = ELFOLDTST

---------------------------------------------------------------------------
# Special needs of this proposal?
This proposal is run to reactivate the COS MAMA following an anomalous shutdown.

Scheduling: As needed

Prerequisites: (e.g., specific SMOV proposal; command development?)

PDB update?               (Specify table name if known e.g. SIAF).
On-board table update?    (Specify table name if known e.g. CCDBadPixelTable)

# Special Requirements:
Real time?                Y
Special commanding?       Y
Quick Data turnaround?    Y (time-tags and engineering telemetry)
Special timing required?  N
Other?                    N
Describe (& justify) special requirements: The engineering telemetry for each step is required to evaluate the safety for proceeding.

-------------------------------------------------------------------------
# Analysis Plan per Anomalous Shutdown

Expected FTE weeks for analysis:                                0.4
Required turnaround on analysis (weeks):                        0.2 per test
Data volume (Mb needed for analysis):                           n/a
Special software needed for analysis? (Describe):               The Engineering Team possesses special COS software used for the fold analysis

Description of analysis Plans: (1-2 paragraphs)

Analysis is carried out by the Engineering Team within 24 hours of each test in the checkout. The engineering telemetry data is examined (voltages, currents, temperatures, relay position, status, and event counts) for agreement with predicted values from previous ground and on-orbit tests or model-predicted values.
The darks and time-tag images are examined for unusual spatial or temporal features.