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 June 1996.
A monthly review for ACIS was conducted at MIT on June 12. Since the main topic was the recent failures with the CCD assemblies, Lincoln Lab supported this review with Jim Gregory and Dick Savoye. The MSFC staff in attendance were Nes Cummings, Max Rosenthal and Buddy Randolph. Harvey Tannenbaum represented the SAO ASC. The next review will be at 9 AM on July 10, and the following review will be on August 20.
A one day TIM was held with LMA on June 13. The main topic was Ellen Sen's preliminary Thermal Vacuum test plan and the implications of a try for 1238 certification of the entire ACIS instrument (less PSMC) at the end of the thermal vacuum exposure at Lincoln Lab (e.g., how to avoid contaminating the instrument with the residue that accumulated on the LN2 shrouds during the T-V test).
The story of the CCD failures got much worse toward the end of the month. Al Pillsbury at LL had begun a thermal cycle test of six units by mid June. Since all three previous failures had involved flexprints from lot 4, it was assumed that we had a bad lot but the others were okay. This was bad enough since half of the calibrated units for the flight focal plane had lot 4 flexprints installed. In the third week of June, Al found that two (of three) lot 4 units under test had failed. However, on June 25, he reported that another unit had failed but this was one of two units with a lot 3 flexprint. The same day, the first results from the flexprint coupon testing at High-Rel were received - failures were experienced in all lots tested. A meeting was quickly called at Lincoln Lab on June 26. In attendance were Mayer, Klatt and Bautz from MIT/CSR, Buddy Randolph from MSFC, and Bernie Kosicki, Al Pillsbury and Keith Percival from Lincoln. The results to date were reviewed, and actions established to try to recover as quickly as possible (see below). There is still some hope that lot 2 is acceptable - the lot 2 under test at Lincoln has not failed and no results have yet been received concerning the lot 2 coupons. [In early July, we found that lot 2 was also bad].
MIT participated in the AXAF project level telecons on June 4, 11, 18 and 25.
MIT participated in the ACIS bi-weekly status review on June 26. Due to the meeting at Lincoln on CCDs (see above), this status review was conducted from Lincoln Labs with the CCD meeting participants contributing to the review. Photos of the failed coupons had been digitized by High-Rel and transferred to MIT via the Internet. MSFC was able to access these photos and display them on a CRT during the monthly review. The review normally scheduled on June 12 was held in person at MIT as part of the Monthly Review.
Usually, the schedule status included in the monthly report is from the last schedule update of the month being reported. In this case, the schedule update is from June 27. Given the CCD problem discussed above and further elaborated below, the ACIS schedule is currently in a state of flux. After the review at Lincoln on June 26, MSFC requested that we generate a schedule based on the currently planned set of verification activities (i.e., install the flight focal plane as soon as it is ready and proceed with testing and verification). Given the fact that the flight focal plane will now not be completed prior to December 1, this results in a delivery of the flight instrument to MSFC on about May 1. Although this is in time for the start of ISIM integration, it does not provide any opportunity for the flight experiment to participate in the XRCF activities at MSFC. This schedule was rejected by MSFC.
Plan 'B' is to proceed with many of the tests with the Engineering Unit of the Detector Assembly (including the engineering unit focal plane), install the flight focal plane in the flight unit Detector Assembly in early December, perform a shake test on the Detector Assembly, a thermal vacuum test on the full ACIS instrument at Lincoln Lab, and deliver the flight instrument to MSFC in early March. This would require that MSFC agree to some verification activities being performed in a non-flight configuration. This plan, and the implications thereof, will be discussed with MSFC at the monthly review on July 10.
The following is a brief summary of the status of other ACIS elements:
(a) The CCD calibration had been completed by about June 15. Obviously, this will have to be redone as soon as refurbished CCDs are available. We expect this activity to re-start about September 1.
(b) The loaded DEA Analog Boards have finally been completed by Sanders and are under test (we are 5 for 5 at last count).
(c) The DPA design is complete. However, we are still testing the ACTEL programs in the two FPGAs on the FEP. The FEPs (less ACTELs) are at Sanders awaiting loading. The BEP flight boards were received about July 1 and we are awaiting the results of the independent coupon testing of these boards prior to final kitting and loading at Sanders.
(d) The testing of the Optical Blocking Filters at PSU is proceeding slowly due to the need for cleanliness. The units are ready for 1238 certification at this point and we don't want to contaminate them now.
(e) The second (Rev B) engineering board of the DEA Interface and Thermal Control Board was received on June 28, loaded over the weekend and put under test on July 2. Testing proceeded throughout the July 4 holidays. In the meantime, the flight units with the new layouts were received from Speedy Circuits on July 1. If acceptable (coupons are being tested), this will complete the fabrication of flight PCBs for the ACIS instrument.
The ACIS project status is now synonymous with CCD status, and the CCD status is still changing on a day-to-day basis. At this writing, the data indicate that we have two problems with the CCD flexprints. The first shows up as failed coupons - "post-separation" - a separation of the internal traces of the multi-layer rigid PCB from the plated through holes or "vias". This separation appears to be caused by smearing of an acrylic adhesive during the drilling operation and inadequate cleaning of the drilled hole - the plated copper is not adhering to the copper traces. This can be fixed by using a different adhesive to bond the layers. However, electrical tests of the failed CCD units show that the failures seen were caused by a shearing of the plated hole itself. This was undoubtedly caused by the severe thermal change when the CCDs are put in calibration (down to -130 deg C). The different thermal coefficient of expansions of copper and polyimide (Kapton) cause the copper to be pulled apart. The latter problem is more difficult to correct. We have contacted many experts and have received help from TRW, Santa Barbara Research Center, and the flexprint engineers at Speedy Circuits, Tyco, and Graphic Research Inc. A meeting is scheduled at Flex Technology, the manufacturer of the failed flexprints, on July 9 to try to understand how the problem happened and put together a design that will work over the large temperature range of the ACIS flexprints. In the meantime, Purchase Orders have been issued to both Flex Technology and Speedy Circuits for more flexprints, but both vendors are on hold for the actual fabrication until the design issues are resolved.
At the end of June, one of the ACIS electrical technicians transferred to another group at MIT. He had received his two month layoff notice on June 1 and was able to find another position at MIT within two weeks. His new supervisor wanted him to start immediately, but we were able to negotiate a July 1 start date. "End of project" layoffs continued with notices given to four staff (three software engineers and a mechanical engineer) on June 30 with a termination date of September 30.
Three front-illuminated flight candidate CCDs were received (w205c2, w210c3, and w215c2, all on 15 June). All of these devices, as well as one device received on 29 May (w203c4) were screened and found to be acceptable for further calibration.
Calibration was completed for w201c3, bringing to 15 the total number of devices calibrated to date.
A number of device tests, in particular with w168c4, were conducted to support diagnosis of the flexprint problem documented elsewhere in this report.
In anticipation of possible device losses during proposed flexprint replacement, six student laboratory assistants were hired and trained to assist with the continuing calibration effort. We plan to calibrate an additional six devices by mid-August.
Several devices were calibrated at the PTB Laboratory at BESSY. Detailed scans of the oxygen K edge were made for two devices using the SX700 monochromator. White-light calibration was performed for two additional devices that had already been calibrated at MIT. Both HETE prototype and ACIS engineering model detector electronics were used for the white-light runs.
The ACIS Contamination Monitor (Door Source) flight unit parts are complete and are being cleaned prior to assembly. The External Calibration Source flight unit parts are complete and are being cleaned prior to assembly.
All of the flight Back Plate Assemblies have been received and leak tested successfully. They are being modified with nine tapped holes each to mount the cable brackets.
The parts of the Proton Shield are complete. Several pieces had been marked with ink and have been undergoing bake-out.
Assembly of the EU support structure continues. The Flight Unit parts have been received from the vendor. The + Y and -Y Panels need EMI gasket grooves machined and all panels need cleaning and painting.
The mechanical parts for the flight unit are being built and are at the plater's.
Operation of the Vacuum GSE has been improved. Tests have been run to determine the pump down and venting rates. These appeared satisfactory. Three pump and vent cycles have been preformed with the Optical Blocking Filters installed. The OBFs survived.
Mechanical GSE to support the Thermal Vacuum testing is being assembled. The XTE ASM shipping container is being modified for use as required. A hoist has been received and will be modified for use with ACIS.
Total instrument weight continues to be well within budget.
The initial release of the Heater Control and Interface CCA B has been completed. The Heater Control and Interface is currently undergoing testing. Further revisions are forthcoming.
The present design of the Detector Assembly Focal Plane flexprint involving the via failures was investigated. A finite element model of the current 0.010 inch diameter hole with .0015 inch thick copper plating, 0.010 inch diameter hole with .0022 inch thick copper plating and 0.014 inch diameter hole with .002 inch thick copper plating were modeled. The temperature dependent properties of the copper was included. The results show that all the design options of the vias experience plastic stresses at temperatures below -30 deg C.
Tantalum radiation shields have been designed for the Detector Electronic Assembly. The -X Cover and +Z panel drawings have been modified to show the additional parts. The shields will be adhered to the panel with Epon 828 epoxy.
After participating in several telecons discussing the thermal environment expected for XRCF testing, MIT engineers grew concerned that the anticipated environment would not provide sufficient heater control for ACIS. During June, we expressed our concerns to TRW and MSFC. We requested further analysis by Ball. Analysis confirmed that ACIS temperatures would fall below operating temperature limits during reduced power modes. By the end of June, TRW and MSFC agreed to supply power to ACIS heaters on the Support Structure, Detector Housing, and PSMC during XRCF calibration.
MIT participated in the Thermal TOP Telecons on 6/6 and 6/20.
MIT efforts to obtain 1443 testing results for the white paint on one DPA panel were rewarded with the good news that the Z93P paint passed 1443 testing at 90 deg C.
The ACIS TV Test thermal model was used to assess the relative merits of several coatings for SIMSIM panels. Black anodized aluminum was selected for its high emittance and ease of application.
On June 13, MIT thermal issues were discussed at length during the monthly TIM with LMA. Group discussions focused on hardware to be used for EU and flight thermal vacuum tests at the LL.
The ACIS TV Test Procedure is nearing completion.
Planning for the ACIS TV Tests continues. GSE hardware was received for the support equipment which will be inside the TV chamber, as well as the bulk of the hardware to build the tipper cart. Demitrios Athens has been briefed on telecommunications issues and is working with LL personnel on them.
For this reporting period, the DEA system is undergoing test and debug. The command set that is controller card specific has been exercised. Testing and evaluation has been complete. Final flight iterations are underway.
Other efforts this month concentrated on the interface evaluation of the interface card and a flight video card. This sequence of tests has shown itself to be successful.
DPA testing and integration is ongoing. We have tested the six engineering FEPs, most of which are loaded with the latest Actels. The DPA boards (and overall system) are undergoing marathon testing along with frequency and voltage margining. The engineering DPA has been configured with an A&B BEP, and tested for primary and redundant operation modes. A full engineering DPA is being "grown" on the bench as the various pieces are ready.
We have the capacity now to run two software stations (one is in full operation) with the engineering DPA boards. We are however lacking one piece of the RCTU simulator, which is on order, but has a long leadtime.
Wire harnesses for in-house functional tests are currently being fabricated. Wire lists and kits for harnesses for the thermal vacuum testing (excluding the LMA fabricated W1 and W2 harnesses) have been completed and sent out to be fabricated after the in-house test harnesses have been completed.
Three "Frame Buffer Boxes" are now operating on SPARCstations supporting FEP/BEP software and hardware integration.
Mechanical fabrication of the LRCTU enclosures is complete and hardware assembly in progress.
Developed versions of sendCmds, SHIM, getPackets, and a utility program that accepts telemetry in the format produced by the Littlefield RCTU and extracts ACIS telemetry. Installed these programs, along with manual pages, in the ACIS test tools directory for use. Began detailed design and started coding a version of getPackets that will accept AXAF-I telemetry minor frames and extract ACIS telemetry packets. Began preparing to support testing at Lincoln Lab. Continued to assist hardware and software developers in troubleshooting GSE-related problems in the lab.
Flight software to verify PRAM loads and prevent excessive numbers of frame transfers is being developed and tested. Changes have been made to FEP code to omit initial CCD flushing (ECO 36-623), and to ignore a specified number of initial exposure frames when computing bias.
Reviewed ECOs relating to the following software modules:
Review materials were shipped from MIT to MSFC on June 28. The review board will meet at MIT on July 8-9. The following documents were distributed:
Added Huffman compression mode to flight software and to test tool (processScience).
All BEP and FEP flight software modules continue to be subjected to unit and coverage tests.
The redesigned BEP has been integrated with a FEP and with an image loader and RCTU emulator. All low-level interface tests are completed without any remaining problems. High-level tests have been run with real CCD images, running the FEP and BEP in timed-exposure mode, computing bias, detecting events, and reporting the bias maps and event lists to the output telemetry.
Rita Somigliana and Jonathan Woo continue to work with the ACIS Test Group to develop software test tools and procedures.
Peter Ford has been absent on sick leave for the entire month.
Fifteen (15) 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. Thirteen (13) of the Alerts listed below do not impact the MIT ACIS design at this time. Two (2) of the Alerts listed below may impact the MIT ACIS design.
Alert EA-P-96-01 (6948) refers to residual gas analysis (RGA) by Oneida Research Services. Oneida is widely used by the semiconductor industry to perform RGA testing as required in Qualification and Quality Conformance Inspection (QCI) for all monolithic and hybrid Microcircuits, Transistors, and Diodes. RGA was done by Oneida on some of the MIT parts in the ACIS. However, MIT does not maintain a record of which subcontractors were used by each manufacturer, for each part type. All other AXAF equipment developers should report the same information back to MSFC.
Alert VV-P-96-01 (6952) refers to element analysis on co-fired ceramic packages supplied by White Microelectronics. The MIT ACIS design employs the White Microelectronics 128K X 32 bit SRAM, P/N WS-128K32-25HQE which has a co-fired ceramic package.
NOTE: It is requested that MSFC provide direction to MIT regarding any action relative to the above two (2) Alerts.
|ALERT #||MSFC #||Part Number and
|QL-S-96-01||6940||EDDINGTON THREAD MFG. CO. V-T-295E, TY 2, CL A||THREAD, 6-CORD, NYLON|
|SM-A-96-01||6941||BUSAK AND SHAMBAN INC. S38420-0450BAK-1||PACKING ASSEMBLY|
|GB7-A-96-01||6942||DEVOE COATINGS 138-K-HR04||COATING COMPOUND, NON-SKID|
|AK-P-96-01||6943||CAL-PACIFIC ELECTRONICS CORP. MIL-W-16878/4||WIRE, ELECTRICAL, INSULATED, PTFE|
|G2-P-96-01||6944||PPC PRODUCTS CORP JANS2N3439||TRANSISTOR, NPN, LOW POWER|
|PRELIM||6932A||NIABCO AND NIBSCO||SAFETY VALVES|
|PRELIM||6932B||NIABCO AND NIBSCO||SAFETY VALVES|
|EA-P-96-01||6948||ONEIDA RESEARCH SERV. RGA TESTING||ALL SEMICONDUCTOR PRODUCTS|
|B8-A-96-01||6951||TEPRO OF FLORIDA INC.||RWR82S1R43FR|
|VV-P-96-01||6952||WHITE MICROELECTRONICS||CO-FIRED CERAMIC PACKAGES|
|F4-S-96-01||6954||ALLIED SIGNAL 3612610-1||GASKET|
|T2-S-96-01||6955||ATHENIS AIRCRAFT SUPPLY||FASTENERS|
|C6-A-96-01||6957||DEUTSCH CO. M39016/9-062P||RELAY, ELECTROMAGNET DPDT|
|BP6-P-96-01||6958||HARRIS SEMICONDUCTOR DG442AAK/883||MICROCIRCUIT, LINEAR, CMOS ANALOG SWITCH|
|AH6-P-96-02||6959||NATIONAL SEMICONDUCT. 54F02, 54F1XX, 54F2XX, AND 54F3XX||MICROCIRCUIT, DIGITAL|
All flight kits involving electronic parts and PC Boards have been completed.
Generated the following complete kits:
|Back end Processor (BEP) Flight||(36-30301)||1 kit|
|Thermal Control Board (A)||(36-20202)||2 kits|
|Thermal Control Board (B)||(36-20262)||1 kit|
|Thermal Control Board (A)||(36-20202)||1 kit|
|LED assembly||(36-10102)||1 kit|
|Cable assembly (FLT)||(see table below)||21 kits|
|BACK END PROCESSOR||3||01,02,03|
|THERMAL CONTROL BOARD 11||2||01,02|
|THERMAL CONTROL BOARD 12||1||01|
|THERMAL CONTROL BOARD 11||1||02A|
|POWER 1 CABLE ASSY., DEA INTERNAL W10||1||001|
|POWER 2 CABLE ASSY, DEA INTERNAL W11||1||001|
|CONTROL 1 CABLE, DEA INTERNAL W12||1||001|
|DIGITAL DATA 1 CABLE, DEA INTERNAL W13||1||001|
|HIGH SPEED DATA CABLE, DEA INTERNAL W15||1||001|
|CONTROL 2 CABLE, DEA INTERNAL W16||1||001|
|THERMISTOR CABLE ASSY, W20||1||001|
|POWER A CABLE ASSY, DPA INTERNAL W10||1||001|
|POWER B CABLE ASSY, DPA INTERNAL W11||1||001|
|DIGITAL DATA 1 CABLE, DPA INTERNAL W12||1||001|
|DIGITAL DATA 2 CABLE, DPA INTERNAL W13||1||001|
|CONTROL 1 CABLE, DPA INTERNAL W14||1||001|
|RCTU A CABLE, DPA INTERNAL W15||1||001|
|RCTU B CABLE, DPA INTERNAL W18||1||001|
|DPA POWER CABLE ASSY, DPA INTERNAL W16||1||001|
|CONTROL 2 CABLE, DPA INTERNAL W19||1||001|
|THERMISTOR CABLE ASSY, DPA RT CABLE W20||1||001|
|CONTROL 1 CABLE ASSY, SUPPORT STR. W4||1||001|
|CONTROL 1 CABLE ASSY, SUPPORT STR. W4||1||001|
|DIGITAL DATA 2 CABLE ASSY, SUPPORT STR. W17||1||001|
|CONTROL 2 CABLE ASSY, SUPPORT STR. W18||1||001|
Final source Inspection was performed at Teledyne on Frame Buffer Microcircuit Memory Modules.
Performed pre-seal visual examination at Q Tech on flight Crystal Oscillators.
Received the analysis results on 2 lots of PWB coupons from HI-REL
Received the analysis results on 16 lots of Rigid-flex circuits from HI-REL
Sent three lots of printed circuit board coupons to HI-REL for cross section analysis.
Sent 3 lots of Rigid-flex circuits to HI-REL.
Sent (5) M38510/32803BRA to SEI for radiation testing
|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
(3M-20 pin Connector/Header)
|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 twenty (20) 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. Four (4) more device types are planned for radiation testing. These are listed above without results.
Three (3) flight CCD/Flex Print assemblies failed and a failure investigation was launched. In all three cases, the failure was fault isolated to open vias in the flex prints. Sixteen (16) coupons, representing sixteen (16) panels were sent to Hi-Rel Laboratories for cross section analysis in accordance with MIL-P-50884. One (1) coupon passed and fifteen (15) coupons failed; primarily for separation of the interlayer metalization from the copper barrel. One (1) failed CCD/Flex print assembly underwent destructive failure analysis. This item was fault isolated to a Z axis failure in a via. The cross section analysis clearly showed a Z axis separation of the via. A meeting was held on 7/9/96 at Flex Technology, the manufacturer of the flex prints. Representatives of Flex Technology acknowledged the failures and launched an investigation into the cause. They stated that it probably was a process problem but could not immediately identify which process or processes were out of control. Due to the wide temperature excursion of these flex prints during the mission, the flex print, and more specifically the vias are being redesigned by MIT/Lincoln Laboratories. New flex prints are being fabricated by Speedy Circuits Inc. and one other manufacturer not yet selected.
Flight Optical Blocking Filters (OBFs) underwent acoustic testing at Lockheed Martin Astronautics (LMA). The OBFs survived the acoustic environment but the light blocking characteristics appear to have changed. The AXAF Science team at PSU is measuring light transmission on these filters. It appears that the 2000TM films which were not "drum tight" may have suffered the most serious degradation. New flight OBFs have been ordered from Luxel for delivery on 9/29/96.
An updated KSC form 16 was sent to Hal Hooper at MSFC.
The MIT license to handle radioactive sources does not include CM244. MIT has requested a revision to the license, which will be sent to MSFC.
The following items were produced or worked on during the reporting period:
Ran first test case successfully on actual flight hardware.
Specified required verification testing for time stamping. This required an extensive review of both the hardware design and detailed software design.
Continued to encounter problems with the test tools. Attempted to document and resolve these.
Identified 782 Verifiable Test Entities (VTE) in the Software Requirements Specification. It is estimated that it will take about 5 man years to test completely. MIT Software QA recommends that at least 190 VTEs be verified to have confidence that the system will perform according to the CEI specification and that the software can be modified. This will take approximately 2 man years. There were 5 new Software Problems Reports generated.
Prepared and presented material for the Software Test Readiness Review. MSFC is aware that we need more time to at least meet the recommended test level addressed above.
There has been no activity on the Performance Assurance and Safety (PAS) Plan. The PAS Plan in effect is revision B.
Completed the design and fabrication of a shroud that will be used for the ATC thermal vacuum chamber.
Cleaned flight inserts and installation tools, for the DPA, DEA, and support structure.
Completed assembly work orders for cleaning, installing inserts, and machining the DEA and DPA panels.
Wrote cleanliness specification for handling the panels during the painting process.
Two of the polyethylene proton shields had yellow highlighter on them as received from the vendor. The shield was cleaned and placed in a thermal vacuum chamber for four days. A new piece of polyethylene, from the original sheet, was also placed in the thermal vacuum chamber to perform a comparison of the RGA scans. There were no differences in the scans.
The Positronics SGMC34FOE1000J0 connectors were placed into a thermal vacuum chamber to monitor the TQCM rate, which turned out to read 1-2 Hz/ Hr.
The 3M 2520-6003UB Heater connectors that originally contaminated Lincoln's chamber were baked again at Lincoln with positive results. The results of the RGA scans revealed that the connectors had cleaned up for flight use.
Disassembled, cleaned, and reassembled the new HEPA filtered oven.
Received the ultrasonic cleaner, but the basket and cover have not been received.
Continuous effort is underway to clean and condition the engineering material to an acceptable level for thermal balance testing at Lincoln Laboratory.
Continuous effort is also underway to clean and vacuum condition flight hardware.
The remaining two back plates arrived. There is an ECO to add holes to the back plates so we will hold off from sending these to LMA for 1238 certification, until the holes are incorporated.
Received MUA-040 and a revised MUA-002 from LMA. MUA-040 was submitted to MSFC but MUA-002 needs some clarification before submittal.
Reviewed AWOs for the PWA fabrication and conformal coating process.
Five devices, including three flight devices, were sent to CSR in June.
Three flight or flight candidate detectors have developed performance anomalies. One is the device mentioned in the last progress report (W163C1 in location I3) that showed a loss of gain in the D quadrant after installation. Two flight candidates also developed anomalies during calibration at CSR. A failure analysis has been performed on each of these failures. All of the anomalies have been attributed to open vias on the flexprint circuits that are attached to the CCD devices.
We have confirmed in two of three of the above devices that inserting a probe down the via in question could "repair" the break, presumably due to plastic deformation of the plated layers. For chip 186C1, we saw that the via was continuous between layers 2 and 4 but not between layers 1 and 2. For 168C4 the break is between layers 1 and 4, while it is between layers 1 and 2 for chip 163C1. The break in 168C4 was only a problem at temperatures above -75C, suggesting that the failure may be related to thermal expansion mismatch problems between the plated copper and the various plastic layers in the flexprint. After this part was "repaired" it was reshipped to campus, but they found it was still not working at room temperature, indicating this repair technique is only temporary.
Flexprints have been fabricated in a total of 5 lots which have been delivered over a 14 month span. Flight detectors have been built using flexprints predominantly from lots 4 and 5. Thermal cycling tests were been initiated to determine if all lots are vulnerable to failure, if there is a common failure mode, and what the failure rate is. After 59 thermal cycles from -150C to +60C there have been failures in 5 of the 6 samples, therefore confirming that thermal stressing is a major cause of the failures. The failed flexprints are from lots 3 and 4. For each circuit that has failed there have been multiple open vias per circuit. Additional samples representing lot 5 are being prepared and will be included in future thermal cycling tests.
An independent laboratory has sectioned coupons from the various lots and concluded that they do not meet workmanship requirements because of separation between the vias and the signal traces. It is not clear yet if this is the major contributor to the failure mechanism or not.
Development of a process to replace flexprints on completed devices has begun. This will allow us to recover devices that presently have bad or suspect flexprints on them. Three devices have been through this process to date. Each has been a low quality device with known defects. The first device showed additional ESD type damage as a result of the replacement process but no visible damage to the detector. The second and third pieces showed no differences in their anomalies and showed no visible damage. The next sample will be a device that has been calibrated at CSR. It will be returned to CSR for comparison after flexprint replacement.
Discussions with various flexprint users and vendors indicates that a possible source of our problems is the use of acrylic adhesive in our flexprints. Its high coefficient of thermal expansion causes excessive strain in the copper vias which eventually fail by fatigue. The industry has been moving towards the use of polyimide adhesive due to its lower thermal expansion coefficient. Talks with alternate flexprint vendors has begun. A contract with a vendor familiar with low expansion circuits should be awarded shortly.
During this month Change Order 28 was negotiated. Preparations are underway to negotiate Change Orders 46 and 43 during July. The program continues to focus on flight hardware fabrication and testing and on resolving day to day situations to maintain schedule. Correspondence has continued on unnegotiated Change Orders to resolve questions and provide clarification on proposal contents and fact finding observations. However, the priority has been placed on the flight hardware and meeting schedule. Due to this priority and limited personnel resources available, the work on Change Order 48 that relates to modifications of the PSMC to accommodate changes in the PSMC to SIM mounting interface was not initiated this month. This work is less critical to the near term LMA schedule and will be started in July. This also allowed Ball Aerospace more time to resolve some uncertainty in the dynamic loads associated with the new interface. The one issue on Change Order 41 remains open but the resolution approach has been coordinated with NASA/MSFC has been agreed to verbally.
The ACIS MIT/LMA Monthly TIM was conducted on June 11/12 at MIT/CSR. LMA participated and provided technical and programmatic status. The primary focus of the TIM was to replan flight systems test and integration activities, owing to the apparent failure of Flexprint Lot #4. An acceptable replan was reached, allowing flight instrument delivery to meet the December 13 promise date.
Major accomplishments for June included completion of the Thermal Control System (TCS) Telescope and Sun Shades fabrication; and completion of the Flight TCS Acoustics Tests. In addition the ACIS Science Instrument Module Simulator (SIMsim) and SIMsim shipping container purchase orders were placed, with delivery expected early in the next reporting period.
The equipment failure of the Zeiss coordinate measurement machine, that occurred late in May, introduced a schedule delay on the Detector Assembly. The corrective action plans, reported in May, have not yet been accomplished due to unexpected difficulties in obtaining replacement parts and scheduling of critical personnel from Zeiss. Work arounds are in place to use a Zeiss located in Colorado Springs, should the schedule so dictate.
The fabrication of the Detector Housing Thermal Controller and the Serial Digital telemetry circuit card assemblies were interrupted due to a solderability issue. An anomalous white powder was accumulating on the PWBs as the assemblies were progressing through fabrication. As this white powder accumulated, soldering was becoming more and more difficult. The PWB manufacturers, Advanced Quick Circuits and the LMA Part Evaluation Lab (PEL) including a company expert, Frank Segura, were involved to assist in the investigation of this contamination. The investigation determined that the white powder was a combination of ionic salts and organic residue. These impurities were determined to have two sources. The first source was residue left as part of the manufacturing process of the PWBs. The second source was an artifact of using IPA as a cleaning agent to remove flux from the assembly. A large amount of the impurities was removed by washing the bare and partially assembled PWBs in a soapy water solution and then in a vapor degreaser bath. The remaining contamination is inconsequential and could be handled with the use of flux as required during the remainder of the fabrication process. IPA will no longer be used as a cleaning agent and will be replaced with Trichloroethane.
All internal PSMC connectors have been received including "sub-D" type.
All circuit card assembly connectors were subjected to a vacuum conditioning bakeout. This connector "prebake" will reduce the required time for vacuum conditioning at the circuit card assembly level.
Other progress includes:
MIT has experienced problems with EU#2 during DPA turn ON. It is our understanding that MIT is resolving the problem with slowing down their turn on circuitry.
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.
It was discovered that the relays manufactured by Leach to a Source Control Drawing (SCD) used within the IO/EMI cavity contained a tin plating. This, of course, is forbidden in space-based applications. These relays are being returned to Leach to replate with tin/lead.
PSMC baseplate analysis will begin in early July.
There are no changes to the MIT load table during this reporting period.
All radiation testing is complete with exception of one part type. The HPCL5731 optoisolator was held up in the PEL during the part upscreening. The concerns of PEL have been addressed and the part testing will begin in July. There is a high degree of confidence because this part type has been subjected to radiation testing in the past and performed adequately.
The Detector Housing has been under vacuum since completion of testing in May. The pre-grinding of the shims was completed in preparation for alignment. Pre-alignment was planned for this month but has not occurred due to an equipment failure of the Zeiss 3 axis coordinate measuring machine. Repair is in process and will hopefully be complete in early July. We have an alternate approach if the Zeiss is not repaired in time to meet our schedule. An outside vendor has the capability to perform the alignment measurements with slightly improved accuracy's. MSFC-SPEC-1238 certification of the detector housing will follow the alignment.
Acoustic testing was completed on the TCS which included the thermal straps, sun shade and telescope shade, warm and cold radiators, thermal standoffs and sun shade support brackets. The test was nominal with no noticeable changes in the frequency responses from the EU acoustic test. All components are now ready for MSFC-SPEC-1238 certification. Pre-bake of the warm/cold radiator assembly has been initiated.
A thermal analysis was completed in support of the pre-alignment machining of the detector housing alignment shims. The analysis assumed that the SIM will be maintained at -10+-5 degrees C during operational phases of the mission. The camera body was assumed to be -60 deg C and the focal plane at -120 deg C. The shims were ground at 5 mils oversize to allow for final adjustments due to tolerance stackups.
Starsys actuator S/N 005 has been returned to Starsys. The X-rays which showed possible problems with seating of the O-rings were also sent back for inspection. Starsys does not believe that the X-rays are adequate and have sent the actuator to Ball Aerospace for additional X-rays. The MARS is still open on this actuator pending a final disposition.
The machining and black anodizing of the SIM Sim details has been completed. Heaters will be installed in early July in preparation for the upcoming Lincoln Labs testing. All heaters and connectors have been received from MIT.
The reports are complete and in review.
The venting subsystem is being assembled. Flight vibration testing is expected to commence early next month after functional testing. A post functional test is planned prior to delivery of the venting subsystem to MIT.
Testing of the low conductance vent valve revealed that seal surface preparation was of extreme importance. Four of nine cleaned valves were found to be leak tight to 1E-8 atm-cc/sec He. Five others showed leakage around the O-ring seals. Five other valves were found to pass leak testing prior to cleaning, these valves will be used for flight spare valves.
All other components of the venting subsystem have been found acceptable for all engineering tests performed.
The Remote Valve Assembly (RVA) has been completely assembled except for two O-rings. The O-rings are in precision cleaning and will be ready for assembly early next month.
Assembly of the Vacuum Control Unit (VCU) is underway. Mechanical assembly of the vacuum system and mounting hardware is nearing completion. The vacuum system will be completed after vibration testing of the flight venting subsystem because the diaphragm pump is used during this test. Electrical assembly of the VCU will begin early next month.
The alignment of the flight detector housing has been delayed because of a mechanical failure in the Zeiss coordinate measurement machine. The failure was corrected but the new parts have forced a remapping of the surface plate. Zeiss has estimated that they will be complete sometime near the middle of July. The accuracy of the Zeiss is required to make the precise measurements needed to maintain the alignment tolerances. In particular the angular requirements are problematic without 0.0001 inch resolution.
Because of the delay we have found a second Zeiss machine available in Colorado Springs. We are currently exploring this option for alignment to minimize shipping delays in the detector housing.
Continued development drawing notes and process to identify specific points in the manufacturing flows for vacuum baking of hardware. Started the baking of Lincoln Labs chamber cables in support of upcoming testing planned at MIT.
Supported preparations for delivery of the Bus Impedance Simulator to MIT. This item is part of the Spacecraft Power Supply Set. Continued surveillance of the ESD efforts at TRW.
Started preparation of the System Safety Analysis report. This analysis report is due out during the next reporting period.
Continued support of drawings release. Attended table top and drawing signature reviews. Continued tracking of parts, materials and processes identification on MIT drawings. Continued the supporting MUA's and MSFC-SPEC-1443 testing.
Started incorporation of the MSFC comments into the ACIS FMEA. This document update is expected to be released in final form during the next reporting period.
The ACIS PTS Specification, PTS to DPS ICD, and Focal Plane to Detector Housing ICD were released to reflect impacts from Change Orders #43 and #46 during this reporting period.
Update of the GSE Specification was released during this reporting period.
Update of the GSE to ACIS and Facilities ICD process continued during this reporting period. A draft version of this ICD release was rescheduled for mid July 1996. A final version will be released following an on-project review and comments incorporation. This is projected for completion on or about 7/31/96.
An update to the program Engineering Procedures Directive (EPD) was released during this period.
The group continued support of the AXAF-I Weekly Action Item Tracking telecon scheduled on Wednesdays.
System design activities continued its focus on supporting update and release of flight hardware engineering during this reporting period.
ACIS System Schematics development continues during this reporting period.
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 during this next period.
Continued surveillance of program scheduling and update of the ground processing flows for testing of ACIS instrument flight hardware throughout June. LMA continues to maintain the ACIS component and system level test flows as a matter of normal business.
Supported reviews and provided liaison with MIT and NASA/MSFC for review, comment incorporation, and approval of formal verification test procedures.
Surveillance of program activities and scheduling of the PTS and ACIS verification events continued throughout June. This activity confirms that the instrument meets requirements and 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.
During this period of performance revision B of the ACIS Verification Plan, ACIS-36-01203 was released.
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 was rescheduled for early July 1996. A final version will be released following an on-project review and comments incorporation. Release is scheduled for the next performance period.
Generation of a PTS Operational analysis was performed during this reporting period. A final version was released following an on-project review and comments incorporation.
Schedule remains the most significant management problem.
Tables' 2-1 through 2-11 summarize our current understanding of the power requirements. This table is the same as that reported in May.
|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 uF||400 uF||1000 uF||1000 uF||500 uF||200 uF||200 to 1400 uF||NA||NA||NA|
|Max. Load Inductance||<1 uH||<1 uH||<1 uH||<1 uH||<1 uH||<1 uH||5 to 40 uH||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.