CCD Imaging Spectrometer
|Submitted to:||Submitted by:|
|George C. Marshall Space Flight Center
National Aeronautics and Space Administration
Marshall Space Flight Center, AL 35812
|Center for Space Research
Massachusetts Institute of Technology
Cambridge, MA 02139
This report covers the period May 1996.
A monthly review for ACIS was conducted at MIT on May 1. LMA supported this review with Lloyd Oldham and Ed Sedivy. The MSFC staff in attendance were Nes Cumings and Buddy Randolph. Paul Plucinsky represented the SAO ASC. [The next two reviews are scheduled for June 12 and July 16 or 17].
As part of the LMA visit to MIT to support the May 1 status review, a short programmatic TIM was held on the afternoon of May 1 before LMA returned to Denver.
MIT hosted a three day visit by the MSFC instrument office from April 30 to May 2. Nes Cumings and Buddy Randolph were here. Buddy returned to Cambridge on May 28 to be the MSFC resident officer at MIT.
MIT participated in the AXAF project level telecons on May 7, 21, and 28. The review normally scheduled for May 14 was cancelled by MSFC.
MIT participated in the ACIS bi-weekly status review on May 15 and 29. The review normally scheduled on May 1 was held in person at MIT as part of the Monthly Review.
During the month of May, the ACIS schedule slipped somewhat. The schedule slack was reduced from 15 days to 9. The critical path shifted from the detector housing to a tie between the flight focal plane (CCDs) and the DEA Interface and Thermal Control Board. However, all main subsystems are experiencing schedule problems.
The following is a brief summary of the main ACIS activities:
(a) The CCD calibration experienced some problems. In mid-May, we had a CCD fail after about three days of calibration. Another unit was substituted while failure analysis was begun. On May 30, one of the completed CCDs which had been installed in the I3 position on the focal plane also failed. The symptom was the same (no output on channel D). A review of our records of all devices received from Lincoln showed that another device had the same problem early on in the calibration program. Therefore, we concluded that we could be experiencing a generic problem common to all CCD assemblies. [The problem was isolated in mid-June to bad flexprints and is not related to the CCDs themselves].
(b) The DEA Analog Boards are still being loaded at Lockheed Sanders. Twelve boards have been loaded, but we are experiencing quality problems with the finished product - they work, but they do not meet the MIT quality requirements. The problems are being resolved, but it is taking time.
(c) The DPA design is complete. However, we are having problems with the printed circuit boards. The BEP boards were delivered on May 2, but we found that the footprint for the FPGA was slightly in error due to an error in the ACIS parts library. The layout was changed and the boards re-ordered. The FEP boards were completed in May, but they all exceeded the max thickness by about 0.010 inch. This would result in a mis-alignment between the connectors on the board and the connectors in the DPA Backplane. After studying the situation for a few days, we concluded that there was enough clearance in the DPA to accept the FEP boards and re-layout the DPA Backplane and have it re-made. With this decision, the FEP boards were accepted and the FEP kits completed and sent to Sanders for loading in early June.
(d) The testing of the Optical Blocking Filters was completed in May. Acoustic tests on four sets were completed on May 30. While none of the filters ruptured, Lockheed Martin noticed that the filters appeared to have developed pin holes as result of the testing. All filters were then sent back to Luxel, Inc, for re-test of their visible blocking parameter.
(e) The testing of the engineering unit DEA Interface and Thermal Control board is taking much longer than planned. This board has been under test since May 16 and there is still quite a bit left to be ironed out. Enough problems have been encountered that we can not fix the situation with a reasonable number of cuts and jumpers. A re-layout of this board is now planned and, while the flight boards are in fabrication, another engineering board will be fabricated, loaded and tested. This slow progress has resulted in the Interface and Thermal Control board now sharing the critical path with the CCD calibration.
Prior to the CCD and OBF problems discussed above, the ACIS project was still holding to a delivery date to MSFC on December 15 (with a positive slack of 9 days) at the end of May. All of the mechanical parts for the DEA, DPA, and Support Structure are in fabrication (with some items completed). The DEA and DPA Backplanes (engineering) have been fabricated and loaded. The DEA Flight Backplane is in-house, while the DPA flight unit is being re-made, as discussed above. We are awaiting the completion of board testing before loading these backplanes with flight connectors. The radioactive source for the flight unit internal source has been ordered from Isotope Products, but one of the engineering units has the correct intensity for flight and is currently at MSFC for cleaning, bakeout and 1238 certification. The Proton Shield (8 separate parts) is in fabrication at a local machine shop. The flight PCB frames (Be) have all been rough machined and the DEA frames are in final machining by a local machine shop (Phoenix Precision).
Just when it seemed that all of the high level technical problems internal to ACIS had been resolved, R&QA became the nemesis. The CCD reliability issue arose on May 30 and this was followed the next day by the news of the OBF light leakage. Both problems were worked in early June and we now believe that both problems are at least understood. However, the ultimate effect on the ACIS schedule has yet to be determined. Recovery plans were discussed for both items at the monthly review on June 12, but the plans are still rather tentative.
At the end of May, one of the ACIS electrical technicians did take the MIT offer of early retirement. A replacement technician was borrowed from Lincoln for two months and he started on June 3. End of project layoffs have begun with three personnel receiving their notices on May 31.
Four front-illuminated flight candidate CCDs were received (w201c3, w202c2, on 15 May, and w203c2 and w203c4, on 29 May). Two of these devices had been screened at month's end; both are acceptable for detailed calibration.
Calibration was completed on five front-illuminated devices (w182c4, w192c1, w190c3, w192c1, w189c2) and one back-illuminated device (w134c4). At month's end, calibration was nearly complete on an additional front-illuminated device (w201c3).
One device (w186c1) failed in the midst of calibration on 20 May. The device was returned to Lincoln Lab for examination. Results of the failure analysis will be reported next month.
The engineering model internal radioactive source was tested with the engineering model collimator. The design was found to be acceptable, although the data showed that the radioactive material in the source was deposited over a larger area than specified by the source control document. It is therefore clear that the flight model source must be tested with the collimator before acceptance of the former.
The ACIS Contamination Monitor (Door Source) engineering unit has been assembled into the Engineering Unit Detector Assembly successfully. The External Calibration Source parts are arriving from the machine shops.
The flight Back Plate Assemblies have been at the vendor for rework. One has been received and is acceptable for flight.
The parts of the Proton Shield are arriving from the vendors.
Assembly of the EU support structure continues. The Flight Unit parts are being machined. The interface of the Flexures to the SIM has been settled and is in the process of being documented. Much effort continues to be spent in developing the routing and supports for the cables from the DA to the DEA. Drawings for the connector brackets for the Survival Heaters and for the thermistors have been completed and are going out for manufacture.
The mechnical parts for the flight unit are being built.
This assembly has been completed. Leak testing was completed satisfactorily. Operation with the Vacuum GSE has revealed several problem areas that will be addressed in the Flight Unit. Vacuum hold times and leak up rates are being measured. A flight set of Optical Blocking Filters was successfully fit checked into the DA.
The design of the DPA Circuit Card Assemblies and the documentation has been completed. The Heater Control and Interface CCA has been redesigned and is presently in engineering review.
All the panels for the DPA and DEA have been received from the outside machine shops. The Detector Electronic and Digital Processing Assemblies are in the MIT machine shop. The housings have been fit checked and the flange machined to the final 0.025 inch thickness and required flatness. The panels are being prepared for the DEA shielding and final painting.
Updated ACIS thermal models to reflect revised cold survival boundary temperatures. Updated ACIS TV Test models to reflect changes in the SIMSIM surface finishes (changed black paint to clear anodized aluminum) which impact the heater panel power necessary to control DEA and DPA soak temperatures.
Participated in XRCF Thermal Telecons on 5/2 and 5/30. All ACIS temperatures are within limits for the 6 CCD hot and cold cases. MIT expressed concern with lack of heaters to have as backup in the event the ACIS operates with less power than during 6 CCD operation.
Participated in AXAF Translation Table Thermal Stability Telecon on 5/28 and TOP Thermal Telecons on 5/9 and 5/23.
Discussed GSE issues for ACIS TV Test in meetings with Don Humphries, designer of ACIS Support Equipment on 5/2, 5/16, and 5/30. Provided list of thermistors for TV Test to M. Doucette and to R. Efromson of LL.
Negotiated with LMA the design details of the SIM Simulator cutouts and surface finishes.
Calculated heater requirements for a contamination bakeout box designed by M. Smith.
Continued work in progress on ACIS TV Test Procedure.
During this reporting period, the DEA effort has been concentrated mainly on the 11th card controller. The testing, debug and performance evaluations of this card are now nearly complete. All re-layout and design changes have been documented. Flight board fabrications will be under way shortly.
The Actel controller on the 11th control card is now undergoing final iteration.
In conjunction with the above efforts, the 12th DEA control card is now ready for testing.
The DEA flight video cards are concurrently being tested as they arrive from Sanders. As of this writing, 4 DEA video cards have been tested and accepted. All x-ray test results are nominal.
Fabrication and development of the DEA Flight test platform continues to progress. At its completion, all flight video cards and the controller cards will integrate into this platform. System level test will commence. If testing at this level passes, the entire structure will be placed into the flight housing.
Three BEP engineering boards are up and running. Detailed diagnostics have been generated for the telemetry command, and FEP interface subsystems. The EEPROM programming interface (via the RCTU) has been tested and we can now download Mongoose s-record files from the UNIX host to the BEP.
In modifying the Littlefield RCTU simulator to match the current RCTU specification, we introduced a noise problem. Apparently the command circuit drivers from the RCTU are much more noise susceptible with the speed-up capacitors added (the latest RCTU driver configuration.) For laboratory use we returned to our previous (quiet) implementation.
Two engineering FEPs have been tested, and six more are built. We are holding off soldering the two FEP Actels until the designs are stable. Detailed testing of the FEP Actels is progressing in parallel with the flight software integration.
Obtained and installed Tk 4.0 and Tcl 7.5, which are considered the latest stable versions, for use in developing GUI's to ACIS EGSE software. Installed Sun and DEC versions in the ACIS tools directory. Assisted Mike Doucette in troubleshooting problems with the Sun version of the high speed parallel interface to his Image Loader. Installed a high speed terminal server hardware and software on a workstation that will be used for ACIS testing. Developed a first version of the "shim" program, which will provide a consistent interface between command writers or telemetry readers and either a CTUE or the locally-developed RCTU emulator. Began putting existing software under version control and installing into the ACIS test tools directory.
Wiring lists for thermal vacuum and in-house functional tests have been reviewed, corrections made and re-checked against "ACIS Wire List" Rev. E.
During testing of the Frame Buffer Boxes it was discovered that the SPARCstation would only download 64k pixels. The failure mechanism was determined (with technical support from manufacturer) and resolved with a minor change in the box DSP code.
Two "Frame Buffer Boxes" are now operating on SPARC stations supporting FEP/BEP software and hardware integration. The third unit is ready to be tested after repairing the DMA interface termination board (wrong size resistor networks were installed).
Machining of the BTU/FLCA test box enclosure has been completed. Previously, the box had thermistor and heater test points for both the Support Structure and Detector Assembly in addition to fiducial light test circuitry. It has been modified so that the thermistor and heater outputs can now be fed to a data logger without having to fabricate a complex harness. The box is now waiting to be wired.
Mechanical fabrication of the LRCTU enclosures is complete and hardware assembly in progress.
DEA PRAM sequences will begin with "normal" exposures, omitting any initial CCD flushing (ECO 36-623). An 'initial frame skip' field will be added to Science Run parameter blocks and will be reflected in changes to ACIS IP&CL.
Reviewed ECOs relating to the following software modules:
Jim Francis attended the AXAF SSWG at MSFC on May 7. Peter Ford attended the TIM at SAO on May 15, and met with the OLS team on the following day. Peter Ford submitted to CSR and ASC a report on long-term maintenance of the ACIS instrument.
Prepared a 'post-Alpha' software load to support the initial phases of integration testing. Released a software package that constructs Huffman compression tables. Prepared preliminary in-house versions of several software test tools, e.g. buildCmds (command generator), process Science(telemetry decoder), genPixelImages (test image generator).
All BEP and FEP flight software modules continue to be subjected to unit and coverage tests.
The BEP redesign is completed, engineering boards are available, and hardware interface testing is nearly done. Flight software integration has commenced with a series of tests of low-level hardware device classes, interrupt routines, etc. Both BEP and FEP boards have been augmented with auxiliary boards containing additional RAM in which to run debugging monitors. These are now working and end-to-end DPA testing has begun.
Jonathan Woo (ASC) has used the software simulator to verify the accuracy of the flight software bias determination and event detection algorithms.
Rita Somigliana, Jonathan Woo, and Peter Ford continue to work with the ACIS Test Group to develop software test tools and procedures. A Software Test Readiness Review will be held early in July.
Seven (7) Alerts from NASA/MSFC, were received over the report period. These items are listed below. These Alerts were compared with the available MIT parts lists. None of the Alerts listed below impact the MIT ACIS design at this time.
|ALERT #||MSFC #||Part Number and
PACIFIC SCIENTIFIC - EDD
PPC PRODUCTS CORP.
DRAM, 16 MEG
NIABCO / NIBSCO
|PRELIM||6935||AIR INTERNATIONAL CORP.
AIR RESOURCES CORP.
AIR TECH INDUSTRIES, INC.
Generated the following complete kits in preparation for fabrication/assembly:
|Thermal Control Board (A)||(36-20202)||1 kit|
|Thermal Control Board (B)||(36-20262)||1 kit|
|Front End Processor (Engineering)||(36-20302)||7 kits|
|Front End Processor (Flight)||(36-30302)||9 kits|
|Power Distribution (Flight)||(36-30317)||2 kits|
|36-002||A to D Converter
|36-003||CA Memory Module
|36-004||FB Memory Module
|36-005||Programmable Supply current
Op Amp 36-02304
Only Memory 36-02306
|36-008||Electrical Connectors, PCB
Mount SND Type
|36-009||Electrical Connectors, PCB
Mount KA Type
|36-012||Junction Field Effect Transistor
|36-013||Dual Surface Mount Diode
|36-014||Dual Operational Amplifier
|36-015||8000 Gate Anti-fuse Field
Programmable Gate Array
|36-017A||Charge Coupled Device
|36-018||Microcircuit, Octal Buffer
|36-019||Microcircuit, Octal Bus
Transceiver (Harris HCS245)
Flip-Flop (Harris HCS374)
Line Driver (Harris HS26C31)
Differential Line Receiver
Q-Tech part type
WIMA P/N FKP2 (36-02312)
|36-025||Wire, Electrical, Nickel
Wirecraft P/N E267U9N
|36-027||Wire, Electrical, Nickel
Specialty Cable AWG26
WIMA P/N FKP2 per
CECC 31 800
|Microcircuit, Rad Hard
|Relay, Latching, DPDT, 5A||4/4/96||4/22/96|
|Microcircuit, Logic, HC||4/4/96||4/22/96*|
|Diode, Rectifier, Schottky||4/4/96||4/22/96*|
|Transistor, Power Switching||4/4/96||4/22/96*|
|Resistor, Precision, Low TC||4/4/96||4/22/96|
|Magnetic Devices -
Transformers and Inductors
Lockheed Martin Astronautics (LMA) has one (1) more NSPAR in process at LMA.
Radiation testing has been completed at Space Electronics, Inc. (SEI) on eighteen (18) device types. Results of these tests are listed below.
|Manufacturer||Part Number||Radiation Test
|Analog Devices||DAC8800BR/883||<2K Rads|
|Com Linear||CLC505A8D||>100K Rads|
|Harris (Chip Supply)||36-02305 (CA 3080)||<100K Rads|
|Analog Devices||OP220AJ/883 (TO-5 can)
|< 20K Rads|
|Texas Instruments||TL082/883B||>100K Rads|
|Analog Devices||REF43BZ/883||>200 K Rads|
|> 100K Rads|
Devices which have not passed 100K Rads of Cobalt 60 testing will be shielded or design work-arounds will be implemented. Six (6) more device types are planned for radiation testing. These are listed above without results.
MIT has prepared non conformance reports on two (2) flight CCDs which have malfunctioned in the "D" quadrant. Fault isolation and failure analysis are in process to provide information for corrective action.
MIT has provided six CS5012A A to D converters (MIT #36-02340.01) to Jim Howard at MSFC and six DAC8800 D to A converters (MIT #36-30201.7026) to Kusam Sahu at Unisys for radiatiion testing.
Supplied calibration enclosure drawings to LMA for radiation safety purposes.
Submitted MIT Incident Report 36-01 to MSFC on the damage of a flight CCD.
The following items were produced or worked on during the reporting period.
Test script developed. (Bad Pixel/Column Definition)
A testing environment was developed for the virtual version of the flight software. This enables us to test some of the software without having physical ACIS hardware.
Set up a system to control development of software tools.
A complete vertical test operation was developed. This involved developing a test script together with the test environment to produce test documentation that ties test results to software development requirements.
There has been no activity on the Performance Assurance and Safety (PAS) Plan. The PAS Plan in effect is revision B.
Located two additional companies, Advanced Technologies in Chelmsford, and Draper Laboratories in Cambridge, that have vacuum chambers which we can use for preconditioning hardware. Each chamber needs modifications before they can be used. Modifications include installation of a heating plate and shroud. We have ordered and received a copper plate, Variac, and thermistors. Minco heaters are on order. The shroud has been designed and is now in fabrication.
FEP and BEP test connectors, 3M 2520-6003UB, contaminated the bakeout chamber during thermal vacuum conditioning. This would be equivalent to the material failing 1443 testing. Further investigation is in process.
Positronic connectors showed signs of significant outgassing. The screws on the connectors had turned black and had a residue left when wiped. Also, the gold plating on the knurled knob part of the jackscrew had a gold colored residue that wiped off with a cloth. The walls of the vacuum chamber had purple and gold residue left on them. The backshell and the screws will not be used on the flight assembly and we will make a new knurled knob for the jackscrew. The chamber was subsequently cleaned and bakeout out at 150 C for two days.
A small thermal vacuum chamber was put together at NE80 that can be used for preconditioning of material.
The CCD assembly clean tent in Building 37 was inadvertently turned off. The room was cleaned and is currently maintaining a class 100 area. There were no CCDs exposed during this time period.
Performed and passed MSFC-SPEC-1238 certification of Lincoln Laboratory chamber for the Focal Plane Subassembly.
Designed and had fabricated, a TQCM holder for use at Advanced Technologies or Draper Laboratory.
Wrote procedures for Conformal Coating, and Electronic Box Cleaning and Cleanliness Control.
Sent a sample of Aeroglaze Z306 black paint to MSFC for 1443 testing.
The last six A grade FI devices were packaged and await testing before shipment to CSR. There are eleven A-devices sawn but are on hold.
Work has continued on installing detectors into the flight detector assembly. The final two detectors were installed into the Imager and their frame store shields installed. We have also found in 163C1 (assembled into the I3 position in the paddle) that sector D now also has a gain of 0, although it was OK when last tested by CSR before return shipment. All other sectors are still operating normally and all parts were operating properly when they left LL and did so over many hours of operation at CSR.
Problems have also developed with the operation of two additional 4FI flight quality parts after many hours of operation. In 186C1, the output is saturated in sector D. Keithley testing here indicates the gain is now only about 15% of its normal value. Part 168C4, sector D, operates on campus only at temperatures below -75 oC, above that temperature the output is saturated. Our measurements indicate a gain of 0 at room temperature. We will perform analysis of the electrical behavior of the component parts and of the flexprints to determine the cause of these problems and potential solutions.
We are placing an order for a new group of flexprints in order to provide a potential fix for these reliability problems. Since Flextech is unable to drill at the proper rpm for 10 mil holes, we have negotiated with them to perform the drilling of the next batch of flexprints here at Lincoln, under their supervision. Work will proceed on the next batch of flexprints and contacts have been established between Flextech and Group 72, to assure that the drilling operation is successful.
Certification of the vacuum chamber used for MSFC-SPEC-1238 vacuum bake-out certifications has been successfully completed.The difference in depositions on the control and sample silicon witness wafers was less than 0.1 angstrom. The worst change in reflectance of the OWS (as measured at MSFC) was 2.3% vs. a specification of 3.0%. The work area was measured as being class 1000 (10,000 requirement) with 3 ppm hydrocarbons vs.a specified limit of 15 ppm.
Preparation of the 17 flexprints recently received has been completed. Three of the flexprints were down graded to non-flight quality due to workmanship defects during initial fabrication. These defects include two holes in the outer layer of Kapton and one entrapped metal particles. Both could have led to shorting of the signal traces to the sputtered gold coating and were thus deemed not acceptable.
One of the flight candidate back illuminated devices (W147C3) had a flexprint that was sputtered with aluminum rather than the more durable gold currently used. The coating was evaluated and found to be one of the best aluminum coatings but did exhibit several small delaminations when subjected to a standard wet wipe test. A previously qualified process to apply metallized kapton tape over the coating was performed successfully to make this device flight worthy.
Change Orders 18, 39 and 42 were definitized this month. However, there has been minimal other Change Order activity. The program focused on flight hardware fabrication and testing and on resolving day to day situations to maintain schedule. Correspondence has continued on Change Orders not yet negotiated to resolve questions and provide clarification on proposal content and fact finding observations. However, the priority has been placed on the flight hardware and meeting program schedule. Due to this priority and limited personnel resources available, the work on Change Order 48, relating to modifications of the PSMC to accommodate changes in the PSMC to SIM mounting interface, was not initiated in May. This work is less critical to the near term LMA schedule and will be started in June. This also allowed Ball Aerospace more time to resolve some uncertainty in the dynamic loads associated with the new interface.
The ACIS MIT Monthly Status Review was conducted on May 1 at MIT/CSR. At this review Mr. Buddy Randolph was introduced as the new NASA/MSFC resident representative to ACIS at MIT. LMA participated in the status review and provided detailed technical and programmatic status. Following this review, a brief ACIS Program Technical Interchange Meeting (TIM) was conducted. Using the same personnel and travel for both meetings enabled LMA and MIT to maximize the work effort directed to maintaining program schedule.
Major accomplishments for May included resolution of the EU #2 PSMC EMC test anomalies and hand carrying that unit to MIT/CSR; completion of NASA-STD 1238 certification bake of the Flight MLI Blankets; completion of the Flight Detector housing Leak Test, Vibration Test and Thermal Cycle Test; completion of the Thermal Control System (TCS) Telescope and Sun Shades Proof Tests; and completion of the Flight Optical Blocking Filters (OBFs) Acoustics Tests. In addition the design of the ACIS Science Instrument Module Simulator (SIMsim) was completed and released for vendor fabrication. Also, the SIMsim shipping container requirements and conceptual design were completed, released for quote and a vendor selected to do the detailed design and container fabrication. The vendors has promised delivery dates that meet the ACIS Program need dates.
One equipment failure occurred late this month that introduced a schedule delay concern of up to two weeks on the Detector Assembly. This was a result of the LMA precision Zeiss coordinate measurement machine failing to pass Detector Assembly pre-alignment calibration. Detailed inspection by Zeiss engineers defined a need to replace some worn parts and recalibrate the system. Although the calibration showed a very small (0.00002 in.) error, an uncertainty in repeatability imposed an need to perform this corrective action before proceeding with this AXAF critical alignment. This corrective action is being expedited and will be accomplished in early June. Work arounds are being investigated to minimize the schedule impact to the ACIS Program.
Component layout issues regarding C/O 43 driven changes to the DEA Power Supply PWB were resolved favorably. Albeit tight, an adequate EEE parts placement was achieved without forcing the PSMC to grow the projected 0.25 inches in the Y direction. The difficulty in achieving an acceptable layout has required additional effort and caused some schedule delay. Board routing will be accomplished early in the next reporting period.
The final baseline MIT load table was submitted by MIT into their ECO process at the end of April, and put under ECO control during the beginning of this reporting period.
Completion of designs and incorporation of Change Order #43 changes into the EU #2 and associated test is complete, as validated by the results from the EU #2 conducted emissions and susceptibility testing completed during May.
Two anomalies were observed during testing; (1) under selected and repeatable load conditions, the power supplies were shutting themselves off, and (2) ripple injected into the PSMC primary power wires during CS01 testing was coupling to the output secondaries between approximately 6 - 10 kHz. Subsequently, these anomalies were resolved by (a) connecting the DPA under/over voltage/ over current comparator to filtered +28VDC rather than raw +28VDC power and, (b) correcting the manner in which secondary returns were grounded in the DEA/DPA load simulator test tool. Item (a) was a previously identified redline that was missed during EU #2 board modifications causing +28VDC noise to trip the comparator, and (2) was an error in the load simulator, causing imbalance in the power supply secondary returns and, in effect, defeating PSMC common mode filtering.
At the conclusion of EU #2 EMC testing, and post test anomaly resolution, the EU #2 PSMC was hand carried to MIT to support testing in Cambridge.
Flight Temperature Control board assembly continued. IO/EMI Filter PWB delivery was held up due to a delay in source inspection, as of the end of May. The flight serial digital PWB was received and is in receiving inspection.
The flight Thermal Control board frame was completed and bought into quality approved ACIS stock. The EMI Cavity mechanical details and preload resistor shelf were also completed and bought into quality approved ACIS stock.
The critical path nature of flight TCS, Venting Subsystem, and Detector Housing assembly and test continues to limit personnel availability to perform the flexure mount driven PSMC mechanical redesign. To accommodate this change, LMA derived an estimated 0.25 inch not-to-exceed height growth for the PSMC. While we will strive to minimize PSMC envelope effects, the 0.25 inch growth limit has tentatively been deemed acceptable by Ball Aerospace.
We currently project the box mechanical redesign and part machining activities to be the schedule limiting element enabling box-level assembly and testing of the fight PSMC. This continues to represent a concern as of the end of this reporting period.
The following additional activities were accomplished:
Parts procurement continues to get significant attention. Delivery of the Harris Rad Hard 9160 transistors was accomplished. The Outside Vendor screening schedule for the Endevco Pressure transducer was condensed into a set of cold calibrations between -55 to -65C and is expected to support flight Detector Housing 1238 baking activities. The transducers are used on the Detector Housing and timely availability was beginning to become a concern. Several sub-D connectors, showing later than desired delivery dates, were expedited and have been received. Receipt of these connectors will enable a connector prebake prior to assembly into the next higher level of assembly (e.g. circuit cards, motherboard, IO/EMI Cavity, etc.). Several work arounds have been initiated for other problem parts. Availability of parts for pre-1238 bake and installation of flight approved parts is continuing to be watched closely.
LMA believes the final ripple effects from C/O 43 redesign have now been fully realized. Therefore, we do not anticipate any additional flight EEE piece part requirements will be generated.
All Test Plans for radiation testing of electronic parts were completed prior to this reporting period. Completion of piece part radiation testing was impeded by breakdowns with the automated test equipment used to control these tests. Test completion for the remaining five of the original twelve part types is rescheduled for a mid June completion.
Fabrication of the Lincoln Labs cable harness was completed. Preparations are in progress for truncating this harness prior to baking at Ball, in preparation for Lincoln Labs thermal vacuum testing.
Assembly of the Flight Detector Housing was completed with very few open items on the build MPPs. There were several MARS on components within the detector and some components from the CAMSIM had to be upgraded to flight. Leak testing was successful with an overnight leak rate that was not measurable. Performance testing of all components including the door mechanism was nominal. Vibration testing was completed in all three axes with no anomalies. Thermal vacuum testing was also completed with 2 cycles from -76C to +46C (-136C on focal plane paddle). All heaters and thermistors including survival heaters were tested. To fully dry out the Torlon standoffs and provide a pre-bake on the detector in preparation for alignment, the detector will be left in the chamber in vacuum until the alignment can be performed in early June.
Proof testing of the sun and telescope shades was completed with no anomalies. Post test NDI will occur in early June. The completion of the shades (i.e. specular liner and MLI post bonding) is being expedited to try and get into acoustic test around June 11. A large defense systems program will need the acoustic chamber for at least a month so we are trying to complete our testing before them.
1238 Pre-bake and certification was completed on the MLI blankets this month. The blankets are ready for installation on the hardware and/or shipment to Lincoln Labs in preparation for thermal vacuum testing.
The spare radiator standoffs were successfully proof tested. All that remains is to apply the gold coating to the standoffs and they should be available for the upcoming acoustic test.
The last of the vibration tests were completed on the EU OBF filter set (Spec. S/N 05 and Imager S/N 08). The latest test used filters that had been irradiated at the cyclotron. The filters were tested in all three axes at 20 torr internal pressure. The pressure was increased to 40 torr in the last 30 seconds of the X axis test to show margin at the same pressure as the filters were tested prior to irradiation. Post test visual inspections without magnification did not show any anomalies.
Acoustic testing was completed on four flight OBF filter sets shown below:
The only test anomaly occurred due to an equipment failure. As the acceptance test was completed on the first set of filters (above), a gain potentiometer failed as it was turned to 0 percent. The detent which was supposed to stop the pot at 0 broke and immediately went to 100 percent gain. The Analog Aborts shut down the test in less than 1 second. The peak acoustic level was around 145 dB compared to the protoflight test level of 139+/-3 dB. The test was continued at the protoflight levels after the equipment was repaired. The CAMSIM detector was not damaged since vibration levels measured on the detector were well below the measured protoflight vibration test levels. Since the OBFs were at 20 torr, they were not damaged either.
Visual Post test inspection of the last filter set to be tested revealed some anomalies on the spectrometry OBF. There were several bubbles in the bond area of the filter which broke exposing the gold plated frame underneath. These could have occurred during initial pump down as the trapped air broke the thin filter material. In addition, a crack or rupture was noted in the filter at the edge of the frame. Illuminating the filter using a flashlight directed at the back side of the filter showed the ruptured area was not opaque and revealed several pin holes. Therefore, the other filters were then inspected using the same technique. This revealed several other filters with pin holes or ruptures. The EU Spectroscopy filter also showed several pin holes. Final disposition on the OBFs will occur next month.
X-rays of the flight actuators showed all O-rings to be seated properly except for one O-ring in S/N 005. The O-ring shows a slight gap between the low pressure seal and the backup O-ring in one of the X-ray orientations. This actuator has been designated as the flight spare and will be sent back to Starsys for their evaluation. A MARS has been opened on the actuator until a final disposition is made. The actuator will be refurbished and its status upgraded back to flight status if necessary.
The design of the SIM Simulator was completed and sent outside for machining. It is on schedule to be ready for the LL T-vac Test. The panels will be anodized to simulate the emmitances of the graphite epoxy structure. Heaters will be installed at LMA.
Completion of the final reports will occur in June.
The flight Venting Subsystem components are all fabricated and ready for assembly. Two sets of vent tubes have been selected and designated as flight and flight spare. O-rings have been purchased, with the proper Viton compound, to replace the original O-rings in the high-conductance vent valve and flanged seals.
The Venting Subsystem is scheduled to go into vibration testing in early June with appropriate pre and post functional tests. Currently we are investigating methods of shipping a fully assembled Venting Subsystem to MIT, to reduce contamination risk and maintain test configuration prior to full system assembly.
Assembly of the Remote Valve Assembly (RVA) continues with completion of the mechanical assembly and partial completion of the vacuum piping and control system. Several O-rings used in RVA valves are in the precision cleaning process. When precision cleaning is complete, RVA assembly will be completed in a few days.
The Vacuum Control Unit (VCU) case has been conversion coated and is being prepared for final modification to bring the hardware to the current revision level. The Engineering Unit VCU showed signs of over temperature when operated for extended periods in high temperature (>90 F) environments. Modifications to the Flight Unit VCU will allow increased airflow on sensitive control electronics and water cooling for the magnetic bearing in the turbo pump. A self contained cooling unit has been added to the VGSE to provide this cooling function.
The ACIS Flight Instrument shipping container has been specified. Currently, several vendors are bidding on the job of detailed design and fabrication. The container is required to be all metal, except for Viton seals, including all metal shock mounts. Purge fittings are available for long-term storage with a filtered vent assembly. The container is designed to be moved with a forklift or pallet jack. Lifting by overhead crane may be performed using slings through the forklift skids. The entire container, with ACIS, will weigh about 550 pounds.
Successful MSFC-SPEC-1238 bakeout and certification of the ACIS MLI Blankets was completed during this reporting period.
The EMI/EMC Test of the EU #2 PSMC was completed during this reporting period. Test anomalies have been investigated and the test report will be released in June.
The ACIS PTS Specification, PTS to DPS ICD, and Focal Plane to Detector Housing ICD have been updated to reflect impacts from Change Orders #43 and #46. These documents were reviewed by MIT during this period, the comments incorporated, and are in review at LMA. They will be completed and presented to MIT for signature by mid June.
Update of the GSE Specification was completed during this reporting period and reviewed by MIT and LMA. Comments will be incorporated and the planned document release is scheduled for 6/21/96
Update of the GSE to ACIS and Facilities ICD continued during this reporting period. A draft version of this ICD release is scheduled for mid June 1996. A final version will be released following an on-project review and comments incorporation. This is projected for completion on about 7/1/96.
Systems Engineering continued support of the AXAF-I Weekly Action Item Tracking telecon scheduled on Wednesdays.
System design activities continued its focus on supporting review, update and release of flight hardware engineering during this reporting period.
ACIS System Schematics development continued during this reporting period. This activity is being closely coordinated with MIT to effectively use common software tools and produce a document useable for fault isolation as well as developing an understanding of the design.
Compatibility Analysis continued during this reporting period. However, progress continues to be limited because of emphasis on other higher priority activities.
Revision E of the ACIS Wire List, ACIS-36-03020.02 was released for program review during this reporting period. Final release is pending review comment coordination and incorporation. Release is scheduled for next month.
Review of program scheduling and update of the ground processing flows for test of the ACIS instrument hardware continued throughout May. LMA continues to maintain the ACIS component and system level test flows as a matter of normal business. Also, reviews were conducted and liaison provided with MIT and NASA/MSFC for review, comment incorporation, and approval of formal verification test procedures.
Review and update of program activities and scheduling of the PTS and ACIS verification events continued throughout May. This activity confirms that the instrument will be ready for delivery to NASA/MSFC at the completion of design, build, and test. LMA continues to perform this activity as a matter of normal business.
Revision B of the ACIS Verification Plan, ACIS-36-01203 was released for on-project review. Release is pending review comment coordination and incorporation. Release is scheduled for this next period.
Update of the Verification Requirements and Specification Document, VRSD, Requirements Compliance Document, ACIS-36-01418 process continued during this reporting period. A review version of this document release is scheduled for mid June 1996. A final version will be released following an on-project review and comments incorporation. Release is scheduled for June.
Generation of a PTS Operational analysis was performed during this reporting period. A review version of this document release is scheduled for mid June 1996. A final version will be released following an on-project review and comments incorporation. Release is scheduled for this next period.
Schedule remains the most significant management problem.
Tables 2-1 through 2-11 summarize our current understanding of the power requirements based on ongoing analyses and coordination. It reflects the load table put under ECO control by MIT.
|DEA_5V||DEA_-5V||DEA_15V||DEA_-15V||DEA_24V||DEA_28V||DPA_5V||DH_HTR||PSMC_MC *||PSMC_ Internal **|
|Vo_Operating_Mode||6.00 V||-6.00 V||15.50 V||-15.50 V||24.00 V||28.00 V||5.00 V||29.00 V||34.00 V||28.50 V|
|Vo_Standby_Mode||6.00 V||-6.00 V||15.50 V||-15.50 V||24.00 V||28.00 V||5.00 V||29.00 V||34.00 V||28.50 V|
|Vo_Bakeout_Mode||6.00 V||-6.00 V||15.50 V||-15.50 V||24.00 V||28.00 V||5.00 V||29.00 V||34.00 V||28.50 V|
|Max. Output Ripple (P-P) mV||100 mV||100 mV||100 mV||100 mV||100 mV||100 mV||100 mV||100 mV||NA||NA|
|Max. Vo Trans. + Ripple (P-P) mV||200 mV||200 mV||200 mV||200 mV||200 mV||200 mV||200 mV||200 mV||NA||NA|
|Max_Operating_Mode_Current||2.14 A||0.82 A||0.44 A||0.31 A||0.11 A||0.15 A||11.55 A||0.29 A||0.00 A||1.56 A|
|Min_Operating_Mode_Current||1.93 A||0.74 A||0.40 A||0.28 A||0.10 A||0.13 A||10.40 A||0.03 A||0.00 A||1.71 A|
|Max_Standby_Mode_Current||0.22 A||0.12 A||0.01 A||0.01 A||0.00 A||0.15 A||1.82 A||0.29 A||0.00 A||1.14 A|
|Min_Standby_Mode_Current||0.20 A||0.11 A||0.01 A||0.01 A||0.00 A||0.13 A||1.63 A||0.03 A||0.00 A||1.22 A|
|Max_Bakeout_Mode_Current||0.22 A||0.12 A||0.01 A||0.01 A||0.00 A||1.40 A||1.82 A||1.81 A||0.00 A||1.68 A|
|Min_Bakeout_Mode_Current||0.20 A||0.11 A||0.01 A||0.01 A||0.00 A||1.26 A||1.63 A||0.00 A||0.00 A||1.47 A|
|OVP Requirement||7.25 V||-7.25 V||18.00 V||18.00 V||28.00 V||35.00 V||6.00 V||NA||NA||NA|
|Max. Fault Current||5.00 A||2.50 A||0.40 A||0.40 A||0.58 A||0.86 A||11.00 A||NA||NA||NA|
|Max. Load Capacitance||400 µF||400 µF||1000 µF||1000 µF||500 µF||200 µF||200 to 1400 µF||NA||NA||NA|
|Max. Load Inductance||<1 µH||<1 µH||<1 µH||<1 µH||<1 µH||<1 µH||5 to 40 µH||NA||NA||NA|
|Max_Operating_Mode_Power||13.50 W||5.18 W||7.21 W||5.06 W||2.83 W||4.32 W||60.64 W||8.50 W||0.03 W||61.62 W|
|Min_Operating_Mode_Power||10.99 W||4.22 W||5.87 W||4.12 W||2.30 W||3.52 W||49.38 W||0.85 W||0.00 W||53.87 W|
|Max_Standby_Mode_Power||1.47 W||0.78 W||0.19 W||0.19 W||0.00 W||4.53 W||9.99 W||8.50 W||0.00 W||49.33 W|
|Min_Standby_Mode_Power||1.08 W||0.58 W||0.14 W||0.14 W||0.00 W||3.33 W||7.36 W||0.85 W||0.00 W||43.04 W|
|Max_Bakeout_Mode_Power||1.47 W||0.78 W||0.19 W||0.19 W||0.00 W||43.12 W||9.99 W||52.56 W||0.00 W||64.91 W|
|Min_Bakeout_Mode_Power||1.08 W||0.58 W||0.14 W||0.14 W||0.00 W||31.75 W||7.36 W||0.00 W||0.00 W||48.66 W|
|Preload||2.65 W||2.65 W||0.24 W||0.24 W||1.15 W||3.81 W||5.51 W|
|DEA Preload total||DEA28 Preload total||DPA Preload total|
|6.93 W||3.81 W||5.51 W|
**Method of calculating min mode currents uses min input bus voltage. This may result in min PSMC internal currents greater than max internal currents. However, this yields true min power dissipation calculations.
|Maximum Operating Dissipation||34.86||60.64||61.62||3.24||8.50||168.87|
|Minimum Operating Dissipation||28.39||49.38||53.87||2.64||0.85||135.12|
|Maximum Standby Dissipation||3.76||9.99||49.33||3.40||8.50||74.97|
|Minimum Standby Dissipation||2.77||7.36||43.04||2.50||0.85||56.51|
|Maximum Bakeout Dissipation||13.41||9.99||64.91||32.34||52.56||173.21|
|Minimum Bakeout Dissipation||9.87||7.36||48.66||23.81||0.00||89.70|
|Maximum Off Dissipation||0.00||0.00||6.21||0.00||0.00||6.21|
|PWR Sppl'd by
|PWR Sppl'd by
|PWR Sppl'd by
|Max_Operating_Power_Dissipation||57.75 W||32.17 W||4.12 W||73%||79%||63%||72%||32%|
|Min_Operating_Power_Dissipation||51.98 W||28.96 W||3.70 W||72%||78%||61%||72%||30%|
|Max_Standby_Power_Dissipation||9.08 W||2.39 W||4.12 W||36%||46%||17%||34%||32%|
|Min_Standby_Power_Dissipation||8.17 W||2.15 W||3.70 W||33%||43%||16%||32%||30%|
|Max_Bakeout_Power_Dissipation||9.08 W||2.39 W||39.20 W||36%||46%||17%||34%||71%|
|Min_Bakeout_Power_Dissipation||8.17 W||2.15 W||35.28 W||33%||43%||16%||32%||70%|
|DEA and DPA Power Supply Efficiency Table||DHTC Efficiency Table|
|DPA PS Max Load Eff||80%||Max_Operating_eff||65%|
|DPA PS Bias Power||10 W||Min_Operating_eff||55%|
|DPA PS Max Load||65 W||Max_Standby_eff||65%|
|DEA PS Max Load Eff||75%||DEA28 PS Max Load Eff||75%||Min_Standby_eff||55%|
|DEA PS Bias Power||4 W||DEA28 PS Bias Power||4 W||Max_Bakeout_eff||80%|
|DEA PS Max Load||52 W||DEA28 PS Max Load||30 W||Min_Bakeout_eff||70%|
|DEA 5V||DEA -5||DEA 15V||DEA -15V||DEA 24V||DEA 28V||DPA 5 V||DH 29V|
|Max Operating Mode||0.794 A||0.457 A||0.169 A||0.135 A||0.074 A||0.199 A||3.217 A||0.158 A|
|Min Operating Mode||0.739 A||0.436 A||0.158 A||0.127 A||0.071 A||0.197 A||3.106 A||0.016 A|
|Max Standby Mode||0.303 A||0.277 A||0.058 A||0.058 A||0.046 A||0.199 A||2.281 A||0.158 A|
|Min Standby Mode||0.297 A||0.273 A||0.058 A||0.058 A||0.046 A||0.197 A||2.263 A||0.024 A|
|Max Bakeout Mode||0.303 A||0.277 A||0.058 A||0.058 A||0.046 A||0.450 A||2.281 A||0.453 A|
|Min Bakeout Mode||0.297 A||0.273 A||0.058 A||0.058 A||0.046 A||0.422 A||2.263 A||0.000 A|
|DEA 5V||DEA -5||DEA 15V||DEA -15V||DEA 24V||DEA 28V||DPA 5 V||DH 29V||Total|
|Max Operating Mode||4.77 W||2.74 W||2.62 W||2.09 W||1.78 W||5.58 W||16.08 W||4.58 W||40.25 W|
|Min Operating Mode||4.44 W||2.61 W||2.44 W||1.97 W||1.72 W||5.50 W||15.53 W||0.46 W||34.67 W|
|Max Standby Mode||1.82 W||1.66 W||0.90 W||0.90 W||1.10 W||5.58 W||11.40 W||4.58 W||27.95 W|
|Min Standby Mode||1.78 W||1.64 W||0.90 W||0.90 W||1.10 W||5.50 W||11.32 W||0.70 W||23.84 W|
|Max Bakeout Mode||1.82 W||1.66 W||0.90 W||0.90 W||1.10 W||12.60 W||11.40 W||13.14 W||43.53 W|
|Min Bakeout Mode||1.78 W||1.64 W||0.90 W||0.90 W||1.10 W||11.82 W||11.32 W||0.00 W||29.45 W|
|DEA 5V||DEA -5||DEA 15V||DEA -15V||DEA 24V||DEA 28V||DPA 5 V||DH 29V|
|Max Operating Mode||0.681 A||0.344 A||0.165 A||0.131 A||0.062 A||0.172 A||3.111 A||0.158 A|
|Min Operating Mode||0.627 A||0.323 A||0.154 A||0.123 A||0.059 A||0.169 A||3.000 A||0.016 A|
|Max Standby Mode||0.190 A||0.164 A||0.054 A||0.054 A||0.033 A||0.172 A||2.175 A||0.158 A|
|Min Standby Mode||0.184 A||0.161 A||0.054 A||0.054 A||0.033 A||0.169 A||2.157 A||0.024 A|
|Max Bakeout Mode||0.190 A||0.164 A||0.054 A||0.054 A||0.033 A||0.423 A||2.175 A||0.453 A|
|Min Bakeout Mode||0.184 A||0.161 A||0.054 A||0.054 A||0.033 A||0.395 A||2.157 A||0.000 A|
|DEA 5V||DEA -5||DEA 15V||DEA -15V||DEA 24V||DEA 28V||DPA 5 V||DH 29V||Total|
|Max Operating Mode||4.09 W||2.06 W||2.56 W||2.03 W||1.49 W||4.82 W||15.55 W||4.58 W||37.18 W|
|Min Operating Mode||3.76 W||1.94 W||2.38 W||1.91 W||1.42 W||4.74 W||15.00 W||0.46 W||31.60 W|
|Max Standby Mode||1.14 W||0.98 W||0.84 W||0.84 W||0.80 W||4.82 W||10.87 W||4.58 W||24.88 W|
|Min Standby Mode||1.11 W||0.96 W||0.84 W||0.84 W||0.80 W||4.74 W||10.79 W||0.70 W||20.77 W|
|Max Bakeout Mode||1.14 W||0.98 W||0.84 W||0.84 W||0.80 W||11.84 W||10.87 W||13.14 W||40.46 W|
|Min Bakeout Mode||1.11 W||0.96 W||0.84 W||0.84 W||0.80 W||11.06 W||10.79 W||0.00 W||26.39 W|
|DEA 5V||DEA -5||DEA 15V||DEA -15V||DEA 24V||DEA 28V||DPA 5 V||Total|
|Max Operating Mode||12.86 W||4.94 W||6.87 W||4.82 W||2.69 W||4.12 W||57.75 W||94.04 W|
|Min Operating Mode||11.57 W||4.44 W||6.18 W||4.34 W||2.42 W||3.70 W||51.98 W||84.64 W|
|Max Standby Mode||1.33 W||0.71 W||0.17 W||0.17 W||0.00 W||4.12 W||9.08 W||15.59 W|
|Min Standby Mode||1.20 W||0.64 W||0.15 W||0.15 W||0.00 W||3.70 W||8.17 W||14.03 W|
|Max Bakeout Mode||1.33 W||0.71 W||0.17 W||0.17 W||0.00 W||39.20 W||9.08 W||50.67 W|
|Min Bakeout Mode||1.20 W||0.64 W||0.15 W||0.15 W||0.00 W||35.28 W||8.17 W||45.60 W|
Electrical power requirements (Watts) are summarized in the following table:
|Peak power distribution
in Standby Mode
|Peak power distribution
in Max. Operating Mode
|Peak power distribution
in Bakeout Mode
|Peak power distribution in
Normal Operating Mode*
Note: Normal operating mode refers to the ACIS operating with six analog chains at full power, six front-end processors at full power, one back-end processor at full power and the focal plane temperature being maintained at -120 deg C.