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WUPPE and Orion


WUPPE OPS MANUAL UPDATE

Volume II - WUPPE Flight Operations Handbook

version December 16, 1994

(Back to Volume 1)

1. Introduction

2. WUPPE Nominal Functional Objective (FO) Procedures

2.1 FO-1 - Activation to Survival
2.2 FO-2A - DEP Activation/Reactivation
2.3 FO-2B - DEP SAA Monitoring
2.4 FO-3A - Detector Activation/Verification
2.5 FO-3B - Detector SAA Monitoring
2.6 FO-4 - Focus & Alignment (WUPPE only operation)
2.7 FO-5 - Observation (WUPPE only operation)
2.8 FO-6 - Deactivation to Survival
2.9 FO-7 - Preparation for Deorbit

3. WUPPE Alternate Procedures (AP)

3.1 AP-01 - Edit Sequence
3.2 AP-02 - Adjust ZOD Magnitude
3.3 AP-03 - Adjust SPEC Magnitude
3.4 AP-04 - Check/Adjust Aperture Position
3.5 AP-05 - Target Not Found in Field
3.6 AP-06 - Manual Locate
3.7 AP-07 - Target Not Acquired in Zoom Locate
3.8 AP-08 - Manual Guide Setup
3.9 AP-09 - Adjust Observation Parameters
3.10 AP-10 - Reprograms PROMs
3.11 AP-11 - Backup Door Operation
3.12 AP-12 - Spectrometer Focus Verification
3.13 AP-13 - Update/Change Special Parameters

4. WUPPE Malfunction Procedures (MP)

4.1 MP-01 - Temperatures Out of Limits
4.2 MP-02A - Door Latch Failure (Fails to Unlock)
4.3 MP-02B - Door Latch Failure (Fails to Lock)
4.4 MP-03 - Heater Volts, Amps Out of Limits
4.5 MP-04 - DEP Error/Crash
4.6 MP-05 - Door Mechanism Failure
4.7 MP-06 - CCTV Display Failure
4.8 MP-07 - Reticon Failure
4.9 MP-08 - Spectrometer High Voltage Anomaly
4.10 MP-09 - TEC Cooling Failure
4.11 MP-10 - CCD Display Failure
4.12 MP-11 - TV High Voltage Anomaly
4.13 MP-12 - Aperture/Filter Mechanism Failure
4.14 MP-13 - Secondary Mirror Mechanism Failure
4.15 MP-14 - IMC HVPS Anomaly
4.16 MP-15 - Target Centering Failure
4.17 MP-16 - IMC Initialization Failure
4.18 MP-17 - IMCE Interface Failure
4.19 MP-18 - Noisy/No IMC Motion
4.20 MP-19 - Guide Initialization Error
4.21 MP-20A - Bright Object Detected During Observation (Sun)
4.22 MP-20B - Bright Object Detected During Observation (Earth)
4.23 MP-21 - Main Electrical Volts/Amps Out of Limits
4.24 MP-22 - LVPS Output Volts Out of Limits
4.25 MP-23 - HVPS Input Volts Out of Limits
4.26 MP-24 - Aperture/Filter Motor Overtemp

5. WUPPE Degraded Modes (DM)

5.1 DM-01 - Loss of DEP
5.2 DM-02 - Loss of thermal control
5.3 DM-03 - Failure of latch sensor
5.4 DM-04 - Failure of latch mechanism
5.5 DM-05 - Failure of door sensor
5.6 DM-06 - Failure of door mechanism
5.7 DM-07 - CCTV Failure
5.8 DM-08 - Reticon Failure
5.9 DM-09 - Loss of spectrometer gain
5.10 DM-10 - Failure of spectrometer detector
5.11 DM-11 - Failure of TEC sensor
5.12 DM-12 - Failure of TEC
5.13 DM-13 - Failure of CCD amplifier
5.14 DM-14 - ZOD Failure
5.15 DM-15 - Loss Of ZOD Gain
5.16 DM-16 - Failure of aperture/filter mechanism
5.17 DM-17 - Failure of aperture/filter sensor
5.18 DM-18 - Failure of secondary mirror mechanism
5.19 DM-19 - Failure of secondary mirror sensor
5.20 DM-20 - Failure of image motion compensation system

1. Introduction

This document is intended as a handbook and reference for WUPPE operations (OPS) and commanding (CMD) personnel working at the Payload Operations Control Center (POCC). It is designed to give an overview of how WUPPE is operated, as well as detailed discussions of procedures from the Payload Flight Data File (PFDF).

2. WUPPE Nominal Functional Objective (FO) Procedures

2.1 FO-1 - Activation to Survival
2.2 FO-2A - DEP Activation/Reactivation
2.3 FO-2B - DEP SAA Monitoring
2.4 FO-3A - Detector Activation/Verification
2.5 FO-3B - Detector SAA Monitoring
2.6 FO-4 - Focus & Alignment (WUPPE only operation)
2.7 FO-5 - Observation (WUPPE only operation)
2.8 FO-6 - Deactivation to Survival
2.9 FO-7 - Preparation for Deorbit

2.1 FO-1 - Activation to Survival

Purpose: The purpose of this FO is to activate the WUPPE temperature monitors and heater banks. After this FO is completed, WUPPE is in a survival state, which means that it is configured to maintain adequate thermal protection for on-orbit exposure to deep space. Engineering data regarding temperatures of primary and secondary mirror cells as well as drive ring temperatures become available once temperature monitoring is enabled. Thermal control by cycling of heater banks becomes active once the heater power is enabled.

The heater power bus also provides power to the WUPPE door latch; this power is available anytime the IPS power bus is powered on (see the Payload Systems Handbook (PSH) for schematics of the electrical layout). The latch must have power available in order to be unlocked - power is used to hold the latch in the unlocked position, so should the heater power bus be lost, the latch will go to the locked position and stay there. Note that this has implications for door operations, since if the door is commanded to close with the latch in the locked position, the door will close and latch. Heater bus power would then be required in order to unlock the latch, else the door could not be reopened.

Instrument status during this FO is monitored on the WAC page, but the data are only available through the Experiment Computer data (ECIO), which is only transmitted during Ku band coverage. If only S band coverage is available, then a limited subset of the WAC page data is available in the PCMMU data stream through the Orbiter Data (OD). A special page display named TBD will be developed and available on the Peripheral Processors (PP) in the POCC in order to display these data.

2.2 FO-2A - DEP Activation/Reactivation

Purpose: The purpose of this FO is to turn on the WUPPE Dedicated Experiment Processor (DEP), which is the "brain" of WUPPE. It is executed at the beginning of the mission (at about MET 0/07:00) during the instrument activation efforts - at this time step 3 of the FO is not executed since these activities (turning on high voltage power supplies and cooling down the thermo-electric cooler [TEC]) are normally done later in the flow of instrument activation. FO-3 can also be executed at any time during the mission when WUPPE has been powered down to survival state; for example, in preparation for shuttle troubleshooting, for protection of the instrument if hardware problems arise, or for any other reason. If FO-3 is being used for reactivation, step 3 is executed. The appropriate steps are generally called out in any procedure (AP or MP) that uses FO-3 for reactivation.

2.3 FO-2B - DEP SAA Monitoring

Purpose: The purpose of this FO is to monitor the memory planes in the DEP during passage through the South Atlantic Anomoly (SAA - a region of higher than normal radiation) in order to determine whether SAA passage causes any errors in the memory. The outcome of this test will determine whether WUPPE operations during SAA should be conducted. No evidence of DEP memory errors during SAA passage was seen on Astro-1. The monitoring is accomplished by running the memory special procedures (ITEM 50_MY) from the WCO page.

2.4 FO-3A - Detector Activation/Verification

Purpose: The purpose of this FO is to verify the operations of the WUPPE detectors after initial activation.

The door is closed and latched, (it was opened in FO-2A for outgassing). Then the test lamp is turned on and observed, allowing verification of the Spectrometer and ZOD detectors, and Filter, Aperture, and Secondary Mirror motors. It is likely that we will need to perform a spiral search to locate the test lamp, because it will probably move due to launch vibrations. TEC cooldown is also accomplished. Note that when the ITEM 2 (BEGIN) command is given, a "WAITING FOR DOOR" message is expected; this tells us that we're trying to observe with the door closed. Acknowledge this by commanding the door closed again (ITEM 19). As a final step, the ZOD magnitude offset is entered from the CUE card.

2.5 FO-3B - Detector SAA Monitoring

Purpose: The purpose of this FO is to monitor the readouts of the detectors (both the spectrometer reticon and the zero-order detector [ZOD] charge-coupled device [CCD]) during SAA passage in order to determine whether SAA passage poses any potential problems for usage of the detectors. The outcome of this test will determine whether WUPPE observations will be conducted during SAA passage. The monitoring is accomplished by running the spectrometer (ITEM 50_SP) and ZOD (ITEM 50_ZO) special procedures from the WCO page.

2.6 FO-4 - Focus & Alignment (WUPPE only operation)

Purpose: The purpose of this FO is to align the WUPPE line of sight with that of the IPS/HUT combination, and to properly focus the telescope. A calibration of the WUPPE observing apertures is also performed.

The target for this FO is a circumpolar star (to allow extended observation during focus and alignment). Since it may get close to the bright earth limb, the Earth BOS is set to the brightest level during this FO. The first steps perform a coarse alignment of WUPPE with the IPS, and measures the IMC performance. This is followed by a fine focus, which selects a focus compromise between the Lyot mode and the half-wave mode. Ray trace pictures of the ZOD image are in the PFDF for comparison. We also perform a knife-edge test using the edge of the aperture. In proper focus, the entire image should disappear simultaneously as it moves out of the aperture. Then mapping of the observing apertures is performed, from a prioritized list found in the JOTP book. This is done by acquiring a diffuse target (Orion Nebula, or Eta Carina Nebula), selecting an aperture, moving the cursor to the center of the aperture with the arrow keys, and initializing the mirror.

The data on focus and aperture position will be folded in to the DWUP02 file for uploading to the WUPPE DEP.

2.7 FO-5 - Observation (WUPPE only operation)

Purpose: The purpose of this FO is to obtain observations of astronomical objects using WUPPE as a standalone instrument. During normal operations, observations will be obtained by using the Joint Operations (JOPS) procedures and the Target Procedures (JOTP) book, which provide the proper procedures for controlling all three telescopes (WUPPE, HUT, and UIT) together as the Astro Observatory.

In general, acquisition will be handled by crew action, while any instrument-specific steps will be by ground command. These steps will be marked in the JOTP book. The APS and/or CIC should be notified prior to ground commanding.

2.8 FO-6 - Deactivation to Survival

Purpose: The purpose of this FO is to close the WUPPE door, warm up the TEC, turn off the WUPPE high voltage power supplies and DEP, and return WUPPE to its survival mode in preparation for stowing the IPS in the cargo bay (or to protect the instrument in the event of problems). Note that except in emergency circumstances, the LVPS should never be powered off prior to completion of the TEC warmup.

2.9 FO-7 - Preparation for Deorbit

Purpose: The purpose of this FO is to completely power down WUPPE, including its heater banks and temperature monitors, in preparation for the return of the shuttle and payload to earth.

3. WUPPE Alternate Procedures (AP)

3.1 AP-01 - Edit Sequence
3.2 AP-02 - Adjust ZOD Magnitude
3.3 AP-03 - Adjust SPEC Magnitude
3.4 AP-04 - Check/Adjust Aperture Position
3.5 AP-05 - Target Not Found in Field
3.6 AP-06 - Manual Locate
3.7 AP-07 - Target Not Acquired in Zoom Locate
3.8 AP-08 - Manual Guide Setup
3.9 AP-09 - Adjust Observation Parameters
3.10 AP-10 - Reprograms PROMs
3.11 AP-11 - Backup Door Operation
3.12 AP-12 - Spectrometer Focus Verification
3.13 AP-13 - Update/Change Special Parameters

3.1 AP-01 - Edit Sequence

Purpose: The purpose of this AP is to allow observing parameters which have been pre-loaded in the star list to be changed to reflect WUPPE operating constraints, PI preferences, or other factors. This procedure will in general be performed by ground command, but the crew can perform it if time permits or the shuttle is in LOS. Sequences can be replaced, added, deleted, or have filter or aperture choices or mode flags changed. Note that if the same sequence is in the preview buffer as the current buffer, edits will go to the preview buffer by default. If you wish to edit the current buffer in this case, clear the preview buffer by previewing dummy sequence number 1.

3.2 AP-02 -Adjust ZOD Magnitude

Purpose: The purpose of this AP is to adjust the sensitivity of the Zero-Order Detector (ZOD) as needed. This may be required if the ZOD is saturating, or if the object is too faint for the DEP to guide or centroid on it. Note that there is a ZOD magnitude offset built into the DEP software which affects the threshhold value; its current value should be recorded on the CUE card.

3.3 AP-03 - Adjust SPEC Magnitude

Purpose: The purpose of this AP is to correct the sensitivity of the spectrometer detector (by adjusting the frame integration time) as needed. If the percent saturation is not in the range from 10 to 50%, or an emission line is saturating, it may be necessary to adjust the Spec Mag. Note that the %SAT value will not be updated until the next frame is complete (indicated by the SEC REM FRM [seconds remaining in frame] value on the WOB page counting down to zero).

3.4 AP-04 - Check/Adjust Aperture Position

Purpose: The purpose of this AP is to allow correction of aperture position data in the event of drift. The numbers measured in this AP should be folded into the DWUP02 file for future uploading to WUPPE. Note that no successful aperture map was done in ASTRO-1, so be prepared for unforeseen circumstances.

3.5 AP-05 - Target Not Found in Field

Purpose: The purpose of this AP is to locate a target when it does not come up in the field of view. This is also known as a "Spiral Search". There are two ways to do this; one is manual, moving the cursor around the CCD area with arrow keys. The other uses a pre-programmed subordinate timeline command. The POCC, if required to perform this AP, will use the manual method. A command display known as TBD has been prepared on the Peripheral Processors (PP) in the POCC to facilitate this procedure. We expect the first targets following launch to require this procedure, and a first target after a prolonged period of WUPPE inactivity or no-guide observations (e.g. a UIT observing block) may also require this procedure during acquisiion.

If there are large mirror offsets or biases at the start of the search, it is possible to hit the mirror limits prior to the end of the search. In this case, perform a mirror reset and repeat this AP. However, beware of offset targets (with planned offsets); be sure to acquire the desired target.

3.6 AP-06 - Manual Locate

Purpose: The purpose of this AP is to allow manual intervention in the locate process. It may be required if there is another bright star near the desired target (a "spoiler star"), or if WUPPE is observing a different target from HUT and UIT (an "offset target"). In general, such targets will be indicated in the JOTP book.

3.7 AP-07 - Target Not Acquired in Zoom Locate

Purpose: The purpose of this AP is to acquire a star which was not automatically found in the zoom mode. Faint or diffuse targets, targets near brighter stars, and poor WUPPE vs. HUT/IPS alignment are possible causes for this condition.

3.8 AP-08 - Manual Guide Setup

Purpose: The purpose of this AP is to allow manual guiding on targets which were planned with this in mind. These might include targets with spoiler stars. The cursor is placed on the desired target, turned off, and the BEGIN (ITEM 7) or PROCEED (ITEM 9) command is issued.

3.9 AP-09 - Adjust Observation Parameters

Purpose: The purpose of this AP is to allow adjustment of observation parameters for the current observation. If the DEP loses lock on the target, or the spec detector saturates, various parameters may need to be adjusted. The proper range for the spectrometer current %SAT is 10% to 50%. Note that the planned LOG-R values displayed are only estimates and may not be reliable.

3.10 AP-10 - Reprogram PROMs

Purpose: The purpose of this AP is to update flight firmware or the starlist. This is an extremely risky proposition, as noise during the reprogramming process can result in the loss of the DEP due to programming errors. If this procedure is not successful in two tries, the POCC should understand why not prior to repeating it. Dumps of DEP memory can be requested from the MUM, and executed via the ECOS to help in debugging.

3.11 AP-11 - Backup Door Operation

Purpose: The purpose of this AP is to operate the door by means of the backup motor mechanism. This mechanism is manual; it must be explicity turned on and off by ITEM entries. Monitor the accelerometer data on the WNG page during door motion. This operation can be done even in the event of a DEP failure.

3.12 AP-12 - Spectrometer Focus Verification

Purpose: The purpose of this AP is to find the best focus for a half-wave observation. The target is a bright emission line star. Parts of the observation are done at the best known focus, and various other focus values in the neighborhood. Be sure to record the focus on entry. The WUPPE TARGETS position will analyze the data after this procedure and choose the optimum focus. Note that this procedure will be done by ground command from the POCC, in which case the PROCEED command (ITEM 9) requires a time period argument. Use something large, as we will be interrupting the observation manually.

3.13 AP-13 - Update/Change Special Parameters

Purpose: The purpose of this AP is to update values of the special parameters which are listed in table REF-5 in the PFDF. Note that values of these parameters should also be incorporated into the DWUP02 file for future use.

Note that during special procedures one is more likely to experience DEP BUSY and CDT ACCESS errors. This can be avoided by shutting down the DEP foreground task (which is taking detector dark background data). Enter the ZOD special procedure (ITEM 50 ZO), and toggle the ZOD scan on and then off again with two ITEM 49 entries. Then proceed to the special procedure as desired, or exit with an ITEM 50 (no argument).

4. WUPPE Malfunction Procedures (MP)

In this section we describe the Malfunction Procedures, the circumstances under which they are used, and things to be aware of during their execution. In the beginning of the MAL section of the WUPPE PFDF there is a list of ECOS and DEP error messages, descriptions, and MPs to be executed in the event of such a message. Note that the text of each error message includes a number (in hexadecimal), and that the messages in the table are listed in order of these numbers for aid in finding them. In general, the crew will execute the MP if such a message is received, but they may request help from the POCC. In other circumstances, the POCC may notice a problem that does not provoke an error message. In each case, the CIC and/or APS should be kept aware of what is going on; the OC can help with procedural details. Many of the MPs call for continued operation in a Degraded Mode; a table of these modes is found in the WUPPE PFDF on page REF-13. (Note that we are extremely reluctant to patch the software on the DEP, so other workarounds are encouraged.)

4.1 MP-01 - Temperatures Out of Limits
4.2 MP-02A - Door Latch Failure (Fails to Unlock)
4.3 MP-02B - Door Latch Failure (Fails to Lock)
4.4 MP-03 - Heater Volts, Amps Out of Limits
4.5 MP-04 - DEP Error/Crash
4.6 MP-05 - Door Mechanism Failure
4.7 MP-06 - CCTV Display Failure
4.8 MP-07 - Reticon Failure
4.9 MP-08 - Spectrometer High Voltage Anomaly
4.10 MP-09 - TEC Cooling Failure
4.11 MP-10 - CCD Display Failure
4.12 MP-11 - TV High Voltage Anomaly
4.13 MP-12 - Aperture/Filter Mechanism Failure
4.14 MP-13 - Secondary Mirror Mechanism Failure
4.15 MP-14 - IMC HVPS Anomaly
4.16 MP-15 - Target Centering Failure
4.17 MP-16 - IMC Initialization Failure
4.18 MP-17 - IMCE Interface Failure
4.19 MP-18 - Noisy/No IMC Motion
4.20 MP-19 - Guide Initialization Error
4.21 MP-20A - Bright Object Detected During Observation (Sun)
4.22 MP-20B - Bright Object Detected During Observation (Earth)
4.23 MP-21 - Main Electrical Volts/Amps Out of Limits
4.24 MP-22 - LVPS Output Volts Out of Limits
4.25 MP-23 - HVPS Input Volts Out of Limits
4.26 MP-24 - Aperture/Filter Motor Overtemp

4.1 MP-01 - Temperatures Out of Limits

Purpose: To correct temperature readings which are too high or too low.

This procedure should be executed if an ECOS message is received that a temperature is out of limits. All of these messages are listed as class E, which means corrective action may be required within an hour. Possible causes include a failed temperature sensor, a heater failed on or off, or environmental factors (hot or cold attitude held for too long). In some cases the procedure calls for negotiation of attitudes, in the event of a hard heater failure.

4.2 MP-02A - Door Latch Failure (Fails to Unlock)

Purpose: To provide guidance in the event of a door latch failure in the locked configuration.

There are two latch mechanisms; the procedure has the user try again using the first mechanism, and then switch to the backup if necessary. Audio feedback is available in the HRM data stream; Sample of latch mechanism sounds are found in the Sounds of WUPPE . Note that if both door latch door mechanisms fail, and the door is open, we can continue operations, but must disable the automatic door operation, since if the DEP closes the door it will latch and remain latched.

4.3 MP-02B - Door Latch Failure (Fails to Lock)

Purpose: Provide guidance in the event that the door latch fails in the open configuration.

There are redundant latch mechanisms; here we try to latch the door using both. If both fail, analysis has shown we can safely de-orbit without latching the door. No damage to any non-WUPPE equipment will occur.

4.4 MP-03 - Heater Volts, Amps Out of Limits

Purpose: Heater power supply malfunction

These error messages (HTR VOLT 15 and HTR CUR 16) are class A errors, which means immediate attention is required. If the voltage is out of limits, the MS will troubleshoot spacelab power buses. If the current is out of limits, heater power is commanded off; cycling the power and switching to backup heaters are tried.

4.5 MP-04 - DEP Error/Crash

Purpose: What to do in the event of a DEP error or crash

There are many symptoms that might lead to this MP, including "instrument behavior not as expected". This involved procedure attempts to find out what is wrong and correct it, often by switching to another RAM bank and/or DEP computer. Note that the combination of DEP B, RAM B is bad and should be avoided. Note also that the DEP BUSY 2E message has been observed from time to time in ground testing under circumstances in which the DEP is fine; try resending the command that led to the error message before coming into this MP.

4.6 MP-05 - Door Mechanism Failure

Purpose: Door mechanism or sensor failure

There are two door mechanisms, but they operate differently. The primary mechanism is mostly automatic; a single command will accomplish opening or closing of the door. The backup mechanism requires a series of commands: ITEM 74/75 (door direction open or closed), ITEM 76 (turn on backup door power), and ITEM 77 (turn off backup door power after door motion is complete). The CUE card covers the procedure for the backup door. Note that audio feedback is available in the HRM data stream (and on the WNG page) when either door mechanism is driving. Sample of primary door sounds are found in the Sounds of WUPPE.

4.7 MP-06 - CCTV Display Failure

Purpose: Closed Circuit Television display failure

If one of the CCTV displays on the flight deck fails, this procedure is followed to determine the cause and remedy the problem. If this is the case, either the TV system is down, or a possible DEP failure has occured (no picture being generated by WUPPE). The TV signal is also sent to the POCC in the HRM stream, so it is possible that the POCC GSE display will appear normal, but the video on the flight deck will be out.

4.8 MP-07 - Reticon Failure

Purpose: Suspected problem with the spectrometer detector

This procedure will be entered in the event of a Spec Init failure, or other problem with the spectrometer detector. This can happen if the TEC is not cold enough when the Spec Init is run. It can also be a hardware problem or a DEP problem.

4.9 MP-08 - Spectrometer High Voltage Anomaly

Purpose: Troubleshooting of the Spectrometer High Voltage supply

The test lamp is observed at 3 different Spec Mag values (5, 3 and 1), and percent saturation (%SAT) is compared to expected values. One possibility is that the Gain Relay has failed, and only certain Spec Gains will be accessible. Upcoming targets will need to be replanned around the bad gain (Degraded Mode 9).

4.10 MP-09 - TEC Cooling Failure

Purpose: Thermo-Electric Cooler failure

There is a TEC on WUPPE to provide refrigeration for the reticon (spectrometer detector), which works best (lowest noise levels) at temperatures of about -40oC. If this fails (message TEC TEMP 03), the temperature sensor or the TEC itself might be at fault. It might be necessary to alter the TEC setpoint, in the event that the TEC underperforms.

4.11 MP-10 - CCD Display Failure

Purpose: Unexpected display on CCTV during activation (FO-3A)

Possible causes are CCD amplifier, oscillator or interface failures, or a failure of the CCD itself. One adjustable parameter is the ZOD mag offset, a number added to selected ZOD (Zero-Order Detector, alias CCD) magnitudes before they are used. If the sensitivity of the ZOD is different from the expected value, this procedure will adjust the sensitivity and allow the POCC to calculate a new value of this parameter.

4.12 MP-11 - TV High Voltage Anomaly

Purpose: Incorrect TV High Voltage feedback during activation (FO-3A)

Possible causes are a sensor failure, ZOD HVPS gain relay failure, or a failure of the ZOD high voltage power supply. The procedure tries adjusting the ZOD mag offset, to test for variations in the ZOD sensitivity.

4.13 MP-12 - Aperture/Filter Mechanism Failure

Purpose: Failure in the Aperture/Filter wheel motor or sensors.

There are two wheels in the optical path, which contain apertures and filters. Under normal conditions, they can be moved at will or in response to observing sequences. If the mechanism fails, it is retried. If the filter mechanism cannot be moved, and filter 2 (the Lyot mode) can be reached, some polarimetry can still be acoomplished. This is the default launch configuration.

4.14 MP-13 - Secondary Mirror Mechanism Failure

Purpose: Failure of the seconday mirror mechanism

The WUPPE secondary mirror is adjustable, to allow correction for misalignment with HUT, observation of a different target near the HUT/UIT target, and to allow compensation for shuttle/IPS jitter (the Image Motion Compensation System, IMCS). In the event of a MIR OVRUN 1D message, or a MIR OFFSET NOGO 36 message, this procedure finds the problem and attempts to correct it. The Degraded Mode Table (page REF-13 in the WUPPE PFDF) calls for a software patch; management & software help is required in this case.

4.15 MP-14 - IMC HVPS Anomaly

Purpose: Failure of Image Motion Compensation system

The IMCS actuator allows WUPPE to compensate for Shuttle & IPS jitter by moving its secondary mirror, using signals from the IMCS instrument elsewhere on the cruciform. Step 5 of FO-3A (the test lamp observation) verifies the operation of the IMCS actuators; this MP refers to that procedure. WUPPE can still do some science without the IMCS (this was done in ASTRO-1); use large apertures if necessary.

4.16 MP-15 - Target Centering Failure

Purpose: Inability to center target in locate aperture

This can result from secondary mirror motor performance problems, and from excessive IPS/IMCS image motion. This procedure calls for IMCS disable and larger apertures as needed to address the problem.

4.17 MP-16 - IMC Initialization Failure

Purpose: Image Motion Compensation initialization failure

This can result from actuator failures, large mechanical shifts during launch, improperly adjusted ZOD magnitude (so the DEP can't find a star), and DEP or DEP interface problems. This procedure steps through the init procedure and tries to find the problem.

4.18 MP-17 - IMCE Interface Failure

Purpose: IMC Interface Failure

After eliminating actuator problems, this procedure tries to correct the problem by swapping DEPs.

4.19 MP-18 - Noisy/No IMC Motion

Purpose: IMC failure

In the event that IMC motion is noisy or absent, the IMC actuators on WUPPE can be disabled, and (if needed) a larger aperture selected. Future sequences then need to be edited to use the larger aperture as well.

4.20 MP-19 - Guide Initialization Error

Purpose: What to do with a GUIDE SEUP LOW 37 error

This error can occur during target acquisition. The procedure talks us through the target acquisition, including giving up and changing to NLOC, NOGD status (no locate, no guide; observe whatever is in the aperture). See the flowchart in Figure REF-4 (page REF-37) in the WUPPE PFDF for criteria to decide whether to issue a BEGIN or a PROCEED when required by the procedure.

4.21 MP-20A - Bright Object Detected During Observation (Sun)

Purpose: Instrument pointed too close to the Sun

The SUN BOS 0D error message is class A, which means immediate attention is required. In the event that the IPS line of sight was not within 30 degrees of the sun, suspect a BOS (Bright Object Sensor) failure or sensitivity problem. Note that if we're using the backup door, it must be closed manually using the procedure on the CUE card.

4.22 MP-20B - Bright Object Detected During Observation (Earth)

Purpose: Earth in field of view

We expect this to occur from time to time, near the beginning or end of the time allotted for a given target, when it is close to the earth limb. If HUT and/or UIT generated a similar message, the detection is probably real, and the procedure tells what to do. If recalibration of the BOS is needed or it fails, the limit can be reprogrammed, or the BOS disabled.

4.23 MP-21 - Main Electrical Volts/Amps Out of Limits

Purpose: Main power out of limits

The MAIN VOLT 11 and MAIN CUR 13 messages are category A, which means immediate attention is required. Possible causes are a DEP crash, which can activate mechanisms & heaters at random; bus voltage low; and a LVPS failure. The attempted remedy may be to swap DEPs and try again, after quickly turning off power to prevent damage.

4.24 MP-22 - LVPS Output Volts Out of Limits

Purpose: Several messages about voltages out of limits

These are class E: some corrective action may be required within an hour. Possible causes include input voltage out of limits, sensor failures, failure of a device driven by the LVPS, and a failure in the LVPS itself. The procedure checks devices driven by the LVPS.

4.25 MP-23 - HVPS Input Volts Out of Limits

Purpose: High Voltage Power Supply input voltages out of limits

This error (HVPS VOLT 07) is a class A error, requiring immediate attention. The procedure calls for immediate shutdown, followed by troubleshooting activity to locate & correct the problem. Some LVPS failures can provoke this message, as well as HVPS failures.

4.26 MP-24 - Aperture/Filter Motor Overtemp

Purpose: Aperture or Filter Motor too hot

These messages (FIL MTR TEMP 12 and AP MTR TEMP 14) are class A errors, requiring immediate attention. Possible causes are sensor failures, motors left on for more than 10 minutes (e.g. at DEP crash), or a short at the motor. The procedure runs an Aperture/Filter verification to locate the problem.

5. WUPPE Degraded Modes (DM)

Many of the degraded modes listed in the table below (and in the PFDF, page REF-13) call for software patches. During Astro-1 an attempted software patch (to update the starlist) caused the loss of a DEP. We are therefore reluctant to patch the software, although in an extreme case we would consider it. If a mal procedure drops us in a degraded mode, consider calling whatever engineering support is required for advice, at any time.

5.1 DM-01 - Loss of DEP
5.2 DM-02 - Loss of thermal control
5.3 DM-03 - Failure of latch sensor
5.4 DM-04 - Failure of latch mechanism
5.5 DM-05 - Failure of door sensor
5.6 DM-06 - Failure of door mechanism
5.7 DM-07 - CCTV Failure
5.8 DM-08 - Reticon Failure
5.9 DM-09 - Loss of spectrometer gain
5.10 DM-10 - Failure of spectrometer detector
5.11 DM-11 - Failure of TEC sensor
5.12 DM-12 - Failure of TEC
5.13 DM-13 - Failure of CCD amplifier
5.14 DM-14 - ZOD Failure
5.15 DM-15 - Loss Of ZOD Gain
5.16 DM-16 - Failure of aperture/filter mechanism
5.17 DM-17 - Failure of aperture/filter sensor
5.18 DM-18 - Failure of secondary mirror mechanism
5.19 DM-19 - Failure of secondary mirror sensor
5.20 DM-20 - Failure of image motion compensation system

5.1 DM-01 - Loss of DEP

As there are only two DEPs, loss of both ends the science part of the mission. Return to survival (using FO-6) and await end-of-mission deactivation.

5.2 DM-02 - Loss of thermal control

Temperature excursions beyond the design limits of the equipment in either direction can cause hardware damage. If thermostatic control is lost, some control can be gained by negotiating benign attitudes (bay to earth, for example). The PSE should be able to help with thermal engineering issues.

5.3 DM-03 - Failure of latch sensor

The POCC can confirm the latch state, due to the audio feedback when it engages. Look at the WNG page (which is not available to the crew). The table calls for a software patch to allow the DEP to open the door while the latch sensor indicates closed. We are reluctant to do software patches, so other workarounds should be sought.

5.4 DM-04 - Failure of latch mechanism

If the latch fails in the locked state, inadvertent closing of the door will cause it to stick shut. Therefore we disable automatic door operations, and use the backup (manual) door if needed.

5.5 DM-05 - Failure of door sensor

If the primary door sensor fails, use the backup door (AP-11). We will probably not patch the DEP software for this fault.

5.6 DM-06 - Failure of door mechanism

Use the backup door mechanism.

5.7 DM-07 - CCTV failure

Automatic acquisition should still work. if HUT is functional, and we know our alignment relative to HUT, they can acquire targets for us. Another option is to use the video signal in the HRM data available on the GSE in the POCC to talk through acquisition.

5.8 DM-08 - Reticon failure

It may still be possible to observe very bright targets; however be careful not to overexpose the ZOD. ZOD safing may be required. Much replanning must be done to find suitable targets.

5.9 DM-09 - Loss of spectrometer gain

If one gain setting is inaccessible, replan targets/observations around it. Sequence edits will be required. The software patch in the table would be to reconstruct the spec mag table so that the bad gain is never used. We prefer editing each sequence to a software patch.

5.10 DM-10 - Failure of spectrometer detector

Safe the instrument and await deactivation and deorbit.

5.11 DM-11 - Failure of TEC sensor

This DM requires a software patch to ignore the bad thermistor. Contact software engineering ASAP.

5.12 DM-12 - Failure of TEC

If the spectrometer detector cannot be kept cold, it will generate noisy data. However, noisy data are better than no data, so observations should continue, though thought should be given to replanning targets appropriate to the state of the instrument.

5.13 DM-13 - Failure of CCD amplifier

Acquisition will be difficult; HUT acquisition may be usable. Sequences may need to be edited to NOGD (no guide). Replan targets as needed.

5.14 DM-14 - ZOD failure

See 5.13 (DM-13)

5.15 DM-15 - Loss of ZOD gain

If one gain setting on the ZOD is unusable, we can replan around it. Sequence edits to change the desired ZOD gain will be needed. A software patch to reconstruct the TV mag table to avoid the bad gain could be considered.

5.16 DM-16 - Failure of aperture/filter mechanism

If there are good positions, use them for observing. Replan targets, and edit sequences to use the available apertures and/or filters.

5.17 DM-17 - Failure of aperture/filter sensor

If the sensor fails, it might be possible to recover the use of the wheel through a software patch. Until then, DM-16 (section 5.16 above).

5.18 DM-18 - Failure of secondary mirror mechanism

If science can be obtained in the current position, replan targets as required to do this.

5.19 DM-19 - Failure of secondary mirror sensor

In this case, the telescope is not usable until a software patch (to ignore the bad sensor) is performed.

5.20 DM-20 - Failure of image motion compensation system

This failure degrades both acquisition and science data. Suggestions include the use of large apertures, and requesting that the crew not exercise during critical WUPPE-prime observations.

WUPPE DEGRADED MODES SUMMARY TABLE

MAL callouts

Degraded Mode (DM)

Failure

Can WUPPE still obtain science data?

Can WUPPE still aquire targets?

S/W patch option?

Procedural notes

Comments

MP-21

MP-4

1

DEP (both)

No

No

 

Return to survival (WUPPE FO-6)

Only one backup DEP; loss of both is unrecoverable

MP-3

2

Thermal control

Limited tgts due to attitude constraints

Yes

 

Negotiate orbiter attitudes

Timeline replanning required

MP-2A

3

Latch sensor

Yes

Yes

Yes

No backup sensor; use POCC audio feedback on WNG (GND only)

Nominal ops; GND can confirm latch state; S/W patch to permit DEP to open closed door

MP-2A

MP-2B

4

Latch mech (both)

Yes, if failed UL or door already open

Yes, if failed UL or door already open

 

If failed LK, disable door and use backup (manual) door to prevent unintentional closing of door.

If lock fails LK with door open, must disable door to prevent shutdown/sun-BOS automatic close (would not be able to UL and reopen)

MP-5

5

Door sensor (prime)

Yes

Yes

Yes

Use backup door (AP-11) until patch

S/W patch to use backup door sensor for DEP door ops

MP-5

6

Door mech (prime)

Yes

Yes

 

Use backup door (AP-11)

 

MP-6

7

CCTV

Yes

difficult

 

Auto-acq only

Use HUT acq if possible; GND ops using HRM video on GSE also an option

MP-7

8

Reticon

No/degraded

Yes

 

Replan target selection

Observe very bright tgts only - may require ZOD safing

MP-8

9

Spec gain

degraded

Yes

Yes

Replan around bad gain

Sequence edits or starlist update req’d; S/W patch to reconstruct spec mag table

MP-7

MP-8

MP-23

10

Spec HV

No

Yes

     

MP-9

11

TEC sensor

Yes

Yes

Yes

 

S/W patch to use only the remaining thermistor

MP-9

12

TEC

degraded

Yes

     

MP-10

13

CCD amp

Yes

degraded

 

Replan sequences if nec.

Use HUT acq if poss.; may req. seq. edits to NOGD

MP-10

MP-11

MP-23

14

ZOD

degraded

No

 

Replan sequences if nec.

Use HUT acq if poss.; may req. seq. edits to NOGD

MP-11

15

ZOD gain

Yes

degraded

Yes

Replan around bad gain

Sequence edits or starlist update req’d; S/W patch to reconstruct TV mag table

MP-12

MP-24

16

Ap/filt mech

No/degraded

No/degraded

 

Replan around good positions if any

Sequence edits or starlist update req’d

MP-12

17

Ap/filt sensor

No/degraded

Yes

Yes

Use DM 16 until patch

S/W patch to work around single bit failure in encoder

MP-13

18

Sec mir mech

No/degraded

No/degraded

 

Replan around current position

 

MP-13

19

Sec mir sensor

Yes

Yes

Yes

Not operable until patch

S/W patch to ignore bad potentiometer

MP-14

MP-16

MP-17

MP-18

20

IMC

degraded

degraded