[CSR]
ACIS-DD-143
June 23, 1997
NAS8-37716
DR SMA03

[AXAF-I]
[ACIS]
Advanced X-ray
Astrophysics Facility

AXAF-I
CCD Imaging Spectrometer

ACIS Monthly Progress Report

April/May 1997

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


1.0 General

This report covers the period from April 1 to May 30, 1997.

1.1 Accomplishments

1.1.1 Program Management

Meetings

Since ACIS was delivered to MSFC on April 14, periodic Monthly Status Reviews have ceased. The last (and final) review was conducted via telecon on March 19.

Telecons

ACIS participated in the weekly AXAF telecons on April 8, 15, 22, and 29, and May 6, 13, 20, and 27. ACIS could not participate in the telecon on April 1 due to a major snow storm which closed MIT (rather rare event).

The FPSI telecons normally conducted on alternate Wednesday mornings have also ceased, since both the HRC and ACIS have been delivered to MSFC.

ACIS Hardware

At Lincoln Lab, work is progressing on the spare flight Focal Plane. A total of 15 flight-quality CCDs are ready for science testing at MIT. In addition, the "XRCF" focal plane, which had been installed in the engineering unit detector assembly and used for the first thermal vacuum test, was returned to Lincoln Lab. The Be paddle will be used for the flight spare, and four CCDs have been re-flexed for use on the spare flight Focal Plane. These last four units consumed the inventory of flight-quality flexprints from Speedy Circuits. The science team will be able to select the ten CCDs for the spare focal plane from an inventory of 15.

The following is a brief summary of the status of the other ACIS elements:

  1. As reported last month, the ACIS flight instrument was delivered, via charter aircraft, to MSFC for XRCF testing at 11 AM on April 14. Rather quickly, it was installed (SIM-SIM and all) on the LASS-Z, the LASS-Z installed on the FAM, and the FAM installed in the T-V chamber. Cables were attached, a short functional test was performed, the chamber was evacuated, and the first X-rays were seen at 2 AM on April 18. From touchdown to X-rays was only 3 days and 15 hours; it had been scheduled to take 7 days.

  2. Testing of ACIS with the flight HRMA continued until 6 AM on April 26. Overall, the instrument worked quite well. The only anomaly noticed was that the pressure in the detector housing at turn on indicated a leak rate of 2.4 Torr per day. The engineering unit detector assembly did much better than this and therefore we believe we have a slight leak in the detector assembly. This will be investigated after the flat-field testing is completed, and prior to the acceptance vibration testing scheduled at MSFC for mid-June.

  3. Flat field testing in the XRCF, without the HRMA, began on May 5 and concluded on May 17. The instrument worked well and no serious anomalies were reported.

  4. Testing of ACIS with the flight RCTU began on May 27 and continued through the end of the month.

  5. The fluorescent Fe55 sources for the external calibration source were completed at Isotope Products and received at MIT on May 12, and the first several units are under test by the science team.

  6. The revised external source holder (needed to accommodate the change from Cu241 to Fe55) was released and has been fabricated and cleaned.

  7. The vibration test unit of the SS/DEA/DPA, fabricated for the purpose of engineering vibration testing to evaluate the loads on the translation table, was completed. It was shipped to MSFC on June 3.

  8. The Detector Assembly mockup test fixture used for vibration testing of the SS/DEA/DPA has been modified to include dummy loads (to simulate the CCDs) and test connectors for the focal plane heaters and thermistors checkout. This will enable the SS/DEA/DPA to be tested, and shipped to BASD, in the vibration configuration.

Schedule Status

The overall ACIS schedule can be expressed in one statement:

"ACIS was delivered to MSFC on April 14"

Monthly Progress Report

Since the hardware has been delivered to MSFC, many of the sections normally included in this report are no longer applicable. Therefore, the report has been shortened to only include sections for which there is still an ongoing activity; namely

  • Project Management
  • Project Science
  • Flight Software
  • Reliability and Quality Assurance
  • Lincoln Lab
  • Lockheed Martin Astronautics

Personnel Status

Due to the positive status of the ACIS instrument and schedule, layoffs are in progress:

Joanne Vining Test tech Left on April 18
Mary Briggs R&QA tech Reassigned to HETG to replace Jeanne Porter (who resigned)
Bob Blozie S/W Verif Eng June 5
Isobe Takashi Science Team June 5
Steve Jones Science Team Will leave about Sept 1 to enter Medical School
Hans Govaert Elec. Eng. Left May 1 on a long-term disability

1.1.2 Project Science

No Flight candidate CCDs were received from Lincoln. One of the two large quantum efficiency measurement chambers (Beavis) was dismantled for cleaning in preparation for re-certification of cleanliness and start of backup focal plane detector calibration next month.

A new measurement technique, originally developed at Osaka University, was applied by Steve Jones and Steve Kissel to map sub-pixel structure in ACIS CCDs. Our measurements represent the first use of this technique at X-ray energies sensitive to details of the gate structure dimensions. A perforated copper sheet, containing 4-micron-diameter holes arranged in a square grid with a 24 micron pitch, was suspended immediately above the surface of a detector. X-ray data were obtained at several energies in the range from 525 eV to 2 keV. Maps of sub-pixel structure, with a spatial resolution of about 4 microns, clearly show channel stops and gate overlaps. These data will be extremely important in constraining models of CCD detection efficiency. Pivovaroff's preliminary analysis shows that the channel stopwidth, in particular, can be measured with an accuracy of order 0.5 micron or better.

We calibrated the flight instrument with the HRMA at XRCF. ACIS performed very well. A remarkably complete data set was obtained in only 8 days of testing. Results will be forthcoming for some time. Flat field testing then continued in May.

We supported our troops at the Science Working Group Meeting 28-29 April 1997 in Huntsville.

1.1.3 Flight Software

Detailed Software Design

The following software ECO has been reviewed this month:

  • ECO 36-889 -- IP&CL Rev J (CCD Protect and 5x5)

It relates to Release 1.3 of the Flight Software, which was burned into the flight instrument during the second period of Thermal Vacuum testing at Lincoln Lab.

External Interfaces

No changes have been made.

Software Delivery

Releases 1.3 and 1.4 of the Flight Software were burned into the flight and engineering units, and are accompanied by release notes and building instructions. Default command blocks, bad pixel lists, etc., were supplied by the ACIS calibration team. Release 1.4 includes the correct default video set points for the flight focal plane.

Unit Testing

All BEP and FEP flight software modules continue to be subjected to unit and coverage tests.

Integration Testing

High-level testing of flight software in FEP and BEP hardware continues, accompanied by tests using the software simulators. The following ECO's related to verification testing were reviewed during the month:

  • ECO 36-881 -- Software Raw Mode Verif. Proc.
  • ECO 36-882 -- Software Telemetry Performance Verif. Proc.
  • ECO 36-908 -- SW Housekeeping Verif. Proc.
  • ECO 36-902 -- SW Exposure Time Verif. Proc.
  • ECO 36-904 -- SW Recompute Bias Verif. Proc.

1 new software problem report has been filed:

  • SPR-106 (M97042401) Two successive stopScience commands fail to drain FEP-BEP ring buffers.

The status may be inspected at the ACIS web server: "http://acis.mit.edu/axaf/spr/" .

Thermal/Vacuum Testing

The Flight Software performed satisfactorily during the second session of thermal/vacuum tests. No new anomalies were noted. Releases 1.3 and then 1.4 were burned into the EEPROMs without any anomaly.

X-Ray Calibration Facility Testing

Jim Francis and Peter Ford conducted ACIS tests at the MSFC facility. An anomaly (SPR-106) was noted when ACIS was (accidentally) run in the next-in-line mode (500 bit per second telemetry) for a period of several hours and then the science run was twice commanded to stop. A small software patch has been created to fix this problem should the circumstances arise in future use.

1.1.4 Reliability and Quality Assurance

1.1.4.1 Quality Assurance

Alerts

Sixteen (16) Alerts from NASA/MSFC were received over the report period. These items are listed on Alert Problem Summary Report dated April 18, 1997, and Alert Problem Summary Report dated May 8, 1997 (copies attached). Each Alert was compared with the MIT ACIS parts lists. None of the Alerts impact the MIT ACIS flight hardware.

Alert Problem Summaries

See Attachment 1 (Alert Problem Summary dated 4/18/97) and Attachment 2 (Alert Problem Summary dated 5/08/97).

Fasteners

A report was sent to Tony Lavoie identifying all fasteners used by Lockheed Martin Astronautics (LMA) on the ACIS flight instrument. All ACIS flight fasteners have now been identified to MSFC.

Source Inspection

Two (2) visits were made to Isotope Products Laboratories (IPL) in Burbank, CA, for final acceptance of the external radioactive sources. During the first attempt, it was determined that the activity level for the aluminum and copper targets was insufficient to produce the reflected output required by the specification. New sources were plated and, after final test and inspection, six (6) sources were accepted. The activity level is relatively high for Fe55 sources, and is reported herein for MSFC information.

Serial
Number
Target
Material
Activity
Level
(mCi)
Leakage
(0.2 max.)
(mCi)
Measured Output
(photons/second/
steradian)
701 Aluminum 105 0.19 1.7803 X 104
702 Aluminum 93 0.02 1.8018 X 104
801 Titanium 13.8 0.00 1.7706 X 104
802 Titanium 11.2 0.00 1.7787 X 104
901 Copper 128.1 0.19 0.8403 X 103
902 Copper 139.0 0.02 0.8910 X 103

Verification Summary Reports

Quality Assurance, Reliability, System Safety Contamination Control, and Software QA are in the process of preparing over 100 Verification Summary Reports for the Acceptance Data Package.

Waiver/Deviation Status

Waivers 36-001 through 36-004, 36-006, 36-009 and 36-011 have been approved by MSFC. Waiver 36-005 and 36-012 through 36-015 are not used. Listed below is the status of the remaining MIT waivers at this time.

Waiver # Description LMA/LL/MIT Submittal Approval
36-007 3% Reflectance loss on OWS for MSFC-SPEC-1238 testing MIT 2/8/96 WITHDRAWN
36-008 AWG26 nickel wire from DA to DEA MIT 2/7/96 WITHDRAWN
36-010 Continuity, IR, and DWV test after harness/cable installation MIT 7/16/96 OPEN
36-016 Use of over-stressed electrical wire in ACIS Flight Cables MIT and LMA 3/28/97 OPEN

1.1.4.2 Parts Engineering

All forty-six (46) ACIS Nonstandard Parts Approval Requests (NSPARs), data requirement SPA 03, have been submitted to and approved by MSFC.

1.1.4.3 Reliability Engineering

All thirty-nine (39) ACIS Material Usage Agreements (MUAs), data requirement SHF04, have been submitted to and approved by MSFC.

1.1.4.4 System Safety

No Activity this month.

1.1.4.5 Software Quality Assurance

Testing

Test Procedures: A total of 16 have been completed. One test procedure was released this month (RawModeTest). Six tests are in the review process (RunFromSlot, Threshold, Graded Threshold, ExposureTime, SwHousekeeping, RecomputeBias). Updated the Overflow Verification procedure (36-57301.04) to reflect CEI requirements and testing operation.

Test Scripts: A total of 11 scripts sets have been completed. 9 have been made into SDM-10 reports.

CEI Requirements: Of the 63 VRSD reports assigned to Software QA, 35 have been completed.

Problem Reports

There have been 5 new problem reports identified this reporting period.

There now are 110 problem reports identified. Of those:

  • 105 have been fixed.
  • 5 are open. Of those:
    • 3 are flight software related and are being worked
    • 1 is test tool related
    • 1 is IP&CL or SRS related.

1.1.4.6 Performance Assurance and Safety Plan

There has been no activity on the Performance Assurance and Safety (PAS) Plan. The PAS Plan in effect is revision B.

1.1.4.7 Cleaning/Vacuum Conditioning and Contamination Control

Preparations were made to reinstall the ACIS into the Thermal Vacuum Chamber at Lincoln Lab for 1238 certification and thermal vacuum testing.

The ACIS was successfully certified to MSFC-SPEC-1238 and delivered to MSFC for XRCF testing.

The ACIS was installed into the XRCF vacuum chamber for calibration.

The Contamination Engineer was present during the majority of critical processes to ensure proper handling of the ACIS.

The chamber named Beavis, that is used for calibrating CCDs, was torn down, cleaned, vacuum-baked and reinstalled. The chamber is in the process of being recertified for cleanliness so that the backup focal plane CCDs can be calibrated. Once this chamber is certified clean ,the remaining chambers will be cleaned in a similar manner.

1.1.5 Lincoln Laboratory

Work proceeded during April and May in packaging of devices to be used in assembling the back-up flight array.

One part, 459C1, was flexed in April with a qualified flexprint, but was not delivered to CSR since they are still evaluating their test chambers for oil contamination.

Two other parts from Lot 14 were put through packaging, but both failed at shorts-opens testing. After analysis, it appears that these parts were probably damaged during sawing. This resulted in a sawing yield of 5/12 for the latest batch of parts (from historical data we would have expected 8/12). Several changes have been made, including change in operator, the inclusion of air ionizer bars on the blue tape machine, the use of a Faraday cage for transporting the sawn parts, and dissipative floor mats. The new operator had been trained properly and had established a yield of 7/8 after sawing practice devices. It is possible that the ESD improvements were responsible for the yield loss, e.g., the air ionizers might be improperly balanced. We are trying to establish what the cause of the failures. Examination of the devices does not reveal any physical damage at 50X.

Chip 186C4 was damaged during reflexing, probably due to ESD. At the deflexing step, a small portion of the chip broke off from the corner near output D. It is possible this fragment ricocheted under the fixture cover and hit the IA, causing a phase 1 to substrate short (note this is not the same mechanism as in the sawn chips mentioned above). This brings us to 27/29 for flexing/reflexing yield.

All sawn parts have been flexed and all parts to be reflexed have been completed. Further flexing will only be done if a flex needs to be repaired.

There are potentially fifteen parts available for populating the flight back-up unit. The disposition is as follows (from Mark Bautz):


Calibrated? Flight Flex?
At CSR
w461c4 y y
w198c1 y y
w210c3 y y
w215c1 n y
w200c1 n y
w216c1 n y
w163c3 n* y
At LL
w192c1 n* y was on xrcf paddle
w185c3 n* y was on xrcf paddle
w78c1 n* y was on xrcf paddle
w202c3 n* y was on xrcf paddle
w163c1r n* y
w168c2r n* y
w459c1 n y
w467c4 n y

Note: n* = calibrated with non-flight flexprint, but needs recalibration after reflexing.

Calibration has not been resumed on campus; as of the end of May there were still problems with fouling of OWSs in the chambers. It is estimated that we can begin to populate the flight spare paddle 6 to 10 weeks after calibration starts up again, since CSR will want to develop some inventory before deciding on chip placement.

Our reflexing yield since last fall has been 17/18, where one part was lost during deflexing, so our ESD yield has been 17/17. These statistics include practice and BI parts.

The flexing yield for newly sawn parts has been complicated by Lot 14 parts (none of which were reflexed). Including first flight paddle, practice, and BI parts, we have an overall yield of 15/27. Of these, 5 were lost to mechanical handling problems, so the ESD pass was 15/22. Breaking this down further, the non-Lot 14 parts had a yield 10/10, but the Lot 14 parts only had a static yield of 5/12. Of these seven failures, six had an IA phase 1 to substrate short and two had an IA phase 1 to phase 2 short. None of the failures involved phase 3 (poly 1). It appears there is a weak spot in the Lot 14 devices that is aggravated by the packaging process, since the static sawing yield was 12/17, very close to our historical 67% yield for sawing all parts, and the dynamic sawing yield was 14/17. The static and dynamic yield of Lot 14 at wafer level was not atypical. A representative failed part has been sent to Hi Rel Labs for analysis, since we are not able to locate the shorts in the IA. The largest difference in processing was during formation of the EGO layers: Lots 9 and earlier had a thermally grown oxide on top of the nitride layer, while Lots 10 and later had a PECVD oxide deposited on the nitride. It is possible that the PECVD glass has a lower threshold to ESD damage. However, wafer-level yields of these lots do not show a difference between pre- and post-Lot 10 devices.

It should be noted that S4 on the first flight paddle is from Lot 14 (W457C4) and three of the parts available now are from Lot 14 (W461C4, W459C1, W467C4). We are not overly concerned about these parts failing later, since they have already been exercised (W457C4 and W467C4 have been cycled and tested extensively during the calibration process), the failures of Lot 14 parts are relatively high impedance, and two parts that failed static testing still passed dynamic testing after static test. It may be we have already culled out infant failures during the packaging process, leaving us with the more robust devices.

The flexprints from Graphics Research Inc. (GRI) have undergone additional evaluation. Two samples were subjected to 400 LN dunks/hot air soaks without failure. Representative vias from both samples were microsectioned to determine if there were any initial signs of an impending failure. No defects were seen that can be attributed to the thermal cycling.

Wire bond tests were performed on the worst of the flexprints and bond strength was acceptable. This verifies the gold plating composition and thickness.

Visual inspection of the GRI flexprints along with our desire to have at least several flexprints from candidate panels (to facilitate the acceptance testing) has identified the best four panels to select candidates from. Tape peel tests were done on each flight candidate flexprint to evaluate gold adhesion. Seventeen of the 24 candidates were deemed to be flight quality. One flexprint from each of these four panels is being built up as a thermal cycle sample to allow acceptance testing of these flexprints.

The existing inventory of Speedy Circuits flexprints has one more flight-qualified flexprint than the identified need. Thus, the GRI flexprints are being evaluated and tested solely to have a reserve inventory of flexprints in case an unexpected need should arise.

Representative flexprint samples from Graphics Research Inc. (GRI) have been prepared for slow thermal cycling. These samples have completed 96 thermal cycles without failure as of the end of May. The remaining 104 cycles will be completed during June.

1.1.6 Lockheed Martin Activities

General

Change Order 67 ,which was prepared and delivered during April, was negotiated on May 21, 1997. This change order added several technical tasks and delayed the date of the ACIS Acceptance Review from 3/15/97 to 6/26/97 and delayed the associated work by approximately three months. The negotiations went very well, effectively laying the groundwork for the LMA overrun proposal. The LMA overrun proposal was completed with the final settlement derived from CO67. The overrun was based on a bottoms-up program Estimate-To-Complete (ETC).

Therefore, all submitted change orders have been negotiated with CO67 awaiting definitization. The LMA Overrun Proposal is the only proposal remaining to be negotiated.

No ACIS NASA/MIT Monthly Status Review nor MIT/LMA Technical Interchange Meetings were conducted this period. Technical coordination was achieved by program telecons and LMA technical personnel supporting hardware integration, test and checkout activities at MIT and MSFC.

The program continued to review internal company Mission Success Bulletins and GIDEP ALERTS received during the month. A LMA internal Mission Success Alert was received that applies to ACIS, involving Johanson ceramic chip capacitors bought to DESC spec 87106. The ACIS PSMC contains Johanson 87106 caps, but earlier lot/date codes than those specified in the alert. A test plan has been established to perform non-destructive screening and DPA testing of lot residuals used in the flight PSMC. Favorable results will exonerate the 87106 capacitors contained in the flight PSMC, which was DD250Őd to MIT earlier this year.

Initial results of the LMA test plan, using lot residuals from the flight PSMC build, yielded acceptable results for the initial low voltage IR test. The 85/85 test is on hold (85°C/ 85% humidity for 240 hours), pending repair of the LMA Thermotron chamberŐs vapor generation unit. For schedule risk reduction, a "rebuy" of 87106 capacitors has been initiated from a different vendor(s). MIT is receiving regular status updates, and concurs with our course of action.

The program continued to place priority and primary emphasis on completion of the ACIS flight and ground support hardware assembly, integration and test at MIT/LL, and MSFC. Efforts are also continuing on the preparation of the final deliverable CDRL documentation and verification reports in conjunction with the ACIS Acceptance Data Package.

Major LMA technical accomplishments for April/May are summarized in the following sections.

1.1.6.1 Power Supply & Mechanisms Controller

At the end of this reporting period, RCTU interface questions still remain regarding the EU2 PSMC. Command interfaces seem acceptable, with some open items involving telemetry interfaces. Sometime after the ACIS XRCF testing, and when a "known good" RCTU is available at CSR, LMA personnel will travel to MIT to resolve these open telemetry interface issues. This is currently an open issue.

Assembly of the flight spare PSMC boards has been completed less a couple of part shortages. The thermal control board is complete, with final QA inspections and MPP signoff planned prior to beginning board-level test. The IO/EMI Cavity is complete with final QA inspections and MPP signoff planned prior to beginning board-level test. Vent Valve & Mechanism Control board assembly is also complete. The DPA power supply is complete. DEA power supply is complete less one part shortage. Motherboard assembly is complete. Testing will commence in early June, beginning with EMI cavity, the motherboard followed by the DPA Power Supply.

LMA is still holding open final PTS flight cable harness verification pending receipt of the MSFC memo and/or MSFC waiver approval. MIT has submitted a waiver to MSFC regarding the issue of DWV testing at voltages that exceed flight wire ratings (waiver # 36-016).

The PTS harness 1238 certification at MSFC is complete. LMA is currently holding these cables prior to delivery to Ball.

There are no changes to the MIT load table during this reporting period.

1.1.6.2 Power Summary

The Power Summary Tables that summarize the power requirements have not changed since the June 1996 progress report. For current Power Summary data, refer to the monthly Progress Reports for June or July 1996. A set of power dissipation measurements, taken during integrated testing at the LMA EMI test chamber, is included with this report.

1.1.6.3 Thermal/Mechanical Design and Testing

Flight Detector Housing And Venting Subsystem Status

The Flight Detector Housing and Venting Subsystem performed well at the XRCF. However, there may be a leak in one of the O-ring seals. After EMI testing is completed, the DEA/DPA/Support Structure will be removed for vibration testing. At that time, the GSE will be hooked up to the Detector to determine the internal pressure after several weeks of exposure to ambient pressure. If the measured pressure indicates a leak, the Balzers Leak Detector will be used to determine the leak source. After the leak is determined, a rework plan will be generated. In addition, final spotbonding and cable tiedown will be completed on the Venting Subsystem and the fiducial lights will be wired to their connector. Random Vibration testing will then be performed on the completed assembly.

Starsys Status

The damaged S/N 005 actuator was sent back to Starsys Research for failure analysis and repair. As suspected, the shear disk was ruptured in the close actuator. No other damage was observed. Both open and close actuators were removed and the mechanism assembly was tested and inspected. As a precaution, the shear disk will also be replaced in the open actuator, which was still functioning. To gain additional information about actuator performance before replacing the shear disk, the undamaged actuator was tested to determine thermistor resistance vs. shaft extension out of the actuator with internal pressures at 90 percent of shear disk capability. The actuator will also be tested at 0.05Ó extension to shear disk rupture. Once this testing is completed, both actuators will be rebuilt and installed in the mechanism assembly so that it can be used as the flight spare.

TCS Status

The new Warm and Cold Strap MLI and connector closeout blankets with grounds are complete and have been 1238 certified. The blankets, shades, and support post will be DD250Őd next month.

Verification Report Status

Only a few reports were outstanding by the end of this reporting period. Completion of the fracture analysis delayed completion of the final stress and dynamic analysis verification reports. These reports will be completed early next month.

Stress/Dynamic Analysis

The fracture analysis CDRL was completed this month and delivered to MIT and MSFC concurrently. The only remaining analysis efforts are the verification reports discussed above.

1.1.6.4 Weight Summary

Since all flight hardware has been built and weighed, there is no update to the weight summary from the previous reporting period. The weight data is shown below:

Table 1. PTS Current Estimated Weight Summary
Assembly Weight, lb. Uncertainty, lb.
Detector Housing 20.8 +0.2
Venting Subsystem 8.7 +0.1
Thermal Control & Isolation 5.4 +0.1
Radiators 10.2 +0.1
Sun & Telescope Shades 16.0 +0.1
Power Supply & Mechanisms Controller 32.7** +0.2
Cables & Connectors 9.1 +0.1
Total Basic Weight 102.9 +0.9 -0.0

Note: Numbers in bold indicate actual measurements.

** Includes Survival Heaters, Thermistors, connectors, and bracket which are not part of ACIS budget. Mark Kilpatrick's (BECD) worksheet dated 12/8/95 assumed 1 pound for these components. LMA does not have an actual breakdown.

1.1.6.5 Mechanical Ground Support Equipment
Venting Subsystem

The new electrical interface bracket with the PIRN-driven changes has been completed by the outside vendor, and is in process for cleaning. It will be ready for delivery to Ball near the end of next month.

Flight Venting Subsystem

No new activities have been performed by LMA on the flight venting subsystem this reporting period.

Mechanical Ground Support Equipment

VGSE paperwork "cleanup" activities have been completed, with all outstanding redlines incorporated. Lifting fixture modification paperwork is underway. Modification to the lifting fixture will take place at LMA; the fixture is currently being used to support vibe tests at MSFC.

Work has begun on disassembling VGSE #1 for cleaning and upgrades. All internal vacuum components are to be cleaned for compatibility with flight hardware, and the electronics brought up to match deliverable unit functionality.

1.1.6.6 Systems Engineering

As reported for the last several months, the systems engineering group continued preparation of verification assessment and test reports for the ACIS compliance verification activities, and continued maintenance of program requirements documents. Engineering specialties activities focused on resolution of EMI/EMC test exceedance investigations. Additionally, the group continued with planning and preparation for delivery of the ACIS Acceptance Data Package (ADP) and CDRL update coordination.

Requirements Identification and Tracking

Updating the final CDRL/SDRL submittals in support of the Acceptance Data Package continued during this month and will continue into next month. The ACIS Wire List was updated to Revision G, incorporating changes per IRN 033 (PIRN 20-0046) and updated to reflect those changes made to the ACIS Cable Interconnection Diagram (36-03020.01) per Revisions S, T and U. Collection of final wiring changes, if any, resulting from the hardware verification activities will be the last input needed to update the ACIS Wire List a final time. The ACIS GSE Specification (36-01102) was updated to Revision A and sent to MIT for final review.

System Design

The Special Consideration Item Drawing (SCID) was completed. This bookform drawing will be used to create the List of Installed Non-Flight Hardware, in support of ADP submittal.

Test Planning and Coordination

The Special Consideration Item Drawing (SCID) was completed. This bookform drawing will be used to create the List of Installed Non-Flight Hardware, in support of ADP submittal.

Verification

Review of program activities and scheduling of the PTS and ACIS verification events continued throughout May. This activity, along with satisfactorily completing scheduled events, will confirm that the ACIS instrument meets requirements. Continued generation and tracking of ACIS and PTS Verification Reports. Continued coordination with MSFC to ensure ACIS verification activities were consistent with MSFC expectations for ADP submittal.

1.1.6.7 Engineering Specialties

Parts Materials and Processes

Continued efforts towards completion of CDRL documentation in support of ADP. Potential issue identified by TRW relative to the current sunshade and telescope shade thermal limit specification exceedances, resulting in shade material strength concerns and end-of-life hot focal plane temperature margin concerns. Although the ACIS shades have been designed, built, and tested in full compliance with Observatory-to-SI ICD requirements, LMA recognizes the need to support investigation of this issue, on a limited basis, to support AXAF program technical and schedule priorities.

Contamination Control

Flight instrument MSFC-SPEC-1238 bakeout activities were completed during this reporting period. The entire ACIS flight instrument has now been 1238 certified with successful certification of the remaining TCS fasteners and MLI blankets at LMA, and the W1 and W2 harnesses at MSFC. Instrument-level (less the above-mentioned hardware) 1238 certification was completed during ACIS performance testing at Lincoln Lab, as reported during the previous reporting period.

EMI/EMC

Planning for instrument EMC retesting at MSFC for compliance with CS01, CS06, RS03 and RE01 continued during this reporting period. Revision to the ACIS EMC Test Plan/Procedure was completed for use during retest activities in June. Successful completion of these tests will resolve three of the four open Requests for Waiver which resulted from the instrument-level EMI/EMC testing performed last December.

System Safety

A revised Hazard Report 16 was not completed, as expected, but is nearing completion. This revised Hazard Report answers the single Action Item received by ACIS during the last Safety Data Review at KSC.

Reliability Engineering

Failure Modes and Effects Analysis, Revision A, and Critical Items List, Revision A, have been reviewed and determined to be acceptable for submittal as part of the ADP.


Last modified: Tue Jun 24 05:15:53 EDT