ACS-R Readiness Status Marco Sirianni TIPS - September

2 September 8, 2008 ACS-R PSR STATUS The hardware after TV, VEST and SMGT testing (Jul-Aug 2008) has been shipped to Florida on September 8. “Pre”-Ship-Review (PSR) done on September 9 The hardware is in its transport module, ready to go. Teledyne is working on the new FAC to be uploaded during SMOV. STScI is working on the implementation of the optimization campaign

3 September 8, 2008 ACS-R PSR Main Program Accomplishments CEB-R Electronics:  Completed FM-1 and FM-2 Flight Assemblies - FM-1 functional and performance test fully successful. Vibration, EMI and Thermal Vacuum tests completed. - FM-2 functional test completed and used for crew fam at KSC and HFMS verification testing.  Completed EM-1, -2, -3 - EM-1 used to test hardware design and in Ops Bench for FSW Development. ASPC/Bias PCB has been updated to flight configuration. - EM-2 used to test 2 nd generation hardware design and sent to Teledyne for FAC V&V Testing. CEB-R will be replaced with either EM-1 or EM-3 for SMOV support. - EM-3 used to test 3 rd and final (Flight) hardware design. Also installed on Ops Bench for VEST and SMGT Testing LVPS-R  One fully flight qualified LVPS-R Electronics,  one spare flight unit  one engineering unit.

4 September 8, 2008 ACS-R PSR ASC-R Hardware Images CEB-R FM-1 LVPS-R FM-1 FM-2 Fitcheck POE Harness PIE Harness

5 September 8, 2008 ACS-R PSR Thermal Vacuum Test Summary & Milestones Test conducted at GSFC in Chamber 238  Hot operate balance EDT  Cold operate balance: EDT  Cold protoflight “balance”: EDT  Hot protoflight “balance”: EDT Thermal cycling comprised of:  2 Survival cycles  5 Cold starts – 3 on Side A, 2 on Side B  1 Hot Start – Side A  12 Protoflight cycles LVPS-R & CEB-R completed thermal vacuum testing on 8/28/2008 with:  Hours of vacuum operation: - Side A: hoursSide B: 63.4 hours  hot protoflight hours 25.7 hot protoflight hours  cold protoflight hours 14.6 cold protoflight hours Test duration from chamber close to test completion  hours or 27.8 days Functionals and performance tests successfully executed at plateaus  Generated over 700 WFC CEB-R images for ACS Science Team

6 September 8, 2008 ACS-R PSR Thermal Vacuum Test As-Run Profile

7 September 8, 2008 ACS-R PSR 7 ACS-R PER Expected Noise performance A (e-)B(e-)C(e-)D(e-) Pre-failure Predicted (DSINT) Predicted (CLAMP) TV Data showed a RN ~ 0.5 e- higher than results obtained at DCL The Ops-bench is supposed to replicate on-orbit MEB with high fidelity, therefore it is likely that the 0.5 extra noise will be also on orbit ACS-R is expected to meet and possibly improve pre-failure readnoise performance

8 September 8, 2008 ACS-R PSR 8 ACS-R PER Crosstalk Meets Specification Crosstalk for the clamp-and-sample video processing chain meets specification of 1 part in (1.6 E-5) Crosstalk for the dual-slope integrator video processing chain is approximately 10 times worse and does not meet STE-83 specification.  Nevertheless, it is very likely acceptable. - Comparable to the old CEB performance. (~9 E-5)  We will continue to investigate the source of this crosstalk. - Further improvement from timing changes (software) may be possible.

9 September 8, 2008 ACS-R PSR Bias Drift A minor bias drift issue was “rediscovered” during TV testing.  The problem is caused by imperfect gain matching between the +1 and -1 gain phases of the Dual-Slope Integrator interacting with the AC-coupling of the detector External Preamp. - The External Preamp is a part of the detector and is not replaced by ACS-R.  The effect is insignificant for Clamp-and-Sample. The effect is small and may or may not require correction.  This is a 0.1% effect on the average intensity in the image.  The mechanism is fully modeled and a correction algorithm has been tested. This was a known effect during ACS-R development.  We had elected not to fix the problem because it was deemed small and correctable.  A change in circuit topology could eliminate this problem. 9 ACS-R PSR

10 September 8, 2008 ACS-R PSR Bias Stability—Mechanism Video signal is AC-coupled. Long term changes in brightness lead to slow variation in DC level.

11 September 8, 2008 ACS-R PSR Bias Stability—Mechanism (Cont’d) Analog Signal Processing Chain (ASPC) should be immune to changes in DC level  Clamp & Sample very good.  Dual Slope Integrator not as good. About 0.1% of the DC level shows up in the output.  Some sensitivity even in Clamp & Sample, due to slope of the DC offset. Hence, a large area of high signal level (planet, e.g.) will cause a shift in the DC level for the next half a row or so.  Including prescan of the next row! Original Image (portion)Residual (10x observed error)

12 September 8, 2008 ACS-R PSR Bias Stability—Level of effect Clamp & SampleDual Slope Integrator

13 September 8, 2008 ACS-R PSR Other items under investigations Minor anomalies have been detected and will be corrected in software with no performance impact.  Board-level thermometry. - The SIDECAR ASIC internal temperature sensor has been calibrated and its temperature will be reported by ground software. - Will be used to supplement board sensors that do not work well at temperatures lower than will be experienced during normal operation.  Smearing observed in half-speed mode in only one data set.  Science data compression with an actual detector uncovered a possible processor utilization problem that manifested in single-bit or multi-bit EDAC errors in the MEB RAM - A solution is expected after more investigation can be performed with either actual detector data or enhanced simulated science data.The realistic data lengthens the time the compression algorithm runs - The remedy for SM4 was the removal of all data compression from the remaining ACS-R SMGT and SMOV  an interrupt code bug has been discovered during Interrupt Stress Test execution on the CEB-R Test Set during training of the FAC long-term maintenance team - Operationally, the only time the code is susceptible is when Gains are being updated (via interrupt) while the Infinite Flush background timing pattern is running. - The code fix is currently being validated by Teledyne and Drop 3.2 will be delivered for uplink sometime during SMOV - the worse case result is a halt of the ASIC for two specific instances of a MOVI instruction being interrupted  When the I’M Alive stops, the MEB will Inhibit Commanding to the WFC - Operational procedures will be used to recover from a WFC Inhibit if it occurs - After thousands of interrupts to Infinite Flush, no additional operational impacts have been seen and the halt has not occurred  The probability of an interrupt command causing a benign problem is 2% - 2.7%  The probability of an interrupt command causing an ASIC halt is % - No indications of this problem have ever been seen during the hundreds of hours on the CEB-R EMs or FMs 13 ACS-R PSR

14 September 8, 2008 ACS-R PSR Optimization Campaign A three-week Optimization Campaign has been allocated during the Servicing Mission Orbital Verification (SMOV) period for ACS-R hardware performance optimization.  Conceptually, this is the replacement hardware “I&T” period with the ACS instrument.  Special diagnostic features have been built into the hardware to support this activity (e.g., the “oscilloscope mode” readout of the raw video signals from the CCDs). For an October 10, 2008 launch, this Optimization Campaign is scheduled to begin on October 26. At the end of this campaign, all programmable adjustments will be completed, and normal scientific operation will resume.  The selectable operating modes will be established and fixed.  STScI will perform detailed recalibration of the ACS immediately following this campaign, in preparation for scientific observations. We can accommodate an early termination of the campaign (after two weeks) if additional testing is not necessary.  Decision needs to be made about a week and a half into the campaign. 14 ACS-R PSR

15 September 8, 2008 ACS-R PSR Optimization Campaign Highlights The Optimization Campaign has 8 iterations of adjustments planned to optimize both the on-orbit CCD performance with the CEB-R, as well as the CEB-R performance in the ACS instrument.  Each iteration concentrates on a particular aspect of performance, and also provides a set of baseline performance tests that summarize the results of the “current” optimized state.  The first 5 iterations cover the anticipated adjustments, as well as we can plan for them.  The last 3 iterations are placeholders to accommodate unknowns. Planning is complicated by the need to establish the Science Mission Specification (SMS) “stored commanding” at least 2 weeks prior to execution. An innovative process for implementing realtime adjustments has been developed to allow for setting the “best current state” before each iteration.  Special kudos to the flight software and operations teams that have worked very hard to make this possible. The first indication of performance will be after installation, with a brief set of Servicing Mission Aliveness and Functional tests.  Major changes to the first week of the Optimization Campaign are probably precluded.  The results from the AT/FT may drive changes to subsequent weeks of the Optimization Campaign. 15 ACS-R PSR

16 September 8, 2008 ACS-R PSR Operating Mode Decisions CEB-R to MEB:  Science data transmission rate. - Controls the speed at which data are transmitted from the CEB-R to the MEB.  Science data control register settings. - Controls the detailed timing for the data transfers relative to the video processing for each pixel.  Both of these are intended to reduce the impact of science data transmission on noise performance and can be determined by a simple test. CEB-R to CCD:  CCD biases and clock voltage rails. - Affects the detailed video waveform presented by the CCDs to the CEB-R.  CEB-R readout timing pattern optimization for the on-orbit CCD. - Affects the detailed video waveform presented by the CCDs to the CEB-R and how the CEB-R interprets the waveform.  Dual-Slope Integrator (DSI) or Clamp-and-Sample (C&S) video processing. - DSI potentially has significantly better noise performance. - C&S replicates the original video processing strategy. 16 ACS-R PSR

17 September 8, 2008 ACS-R PSR Optimization Campaign The optimization program has been implemented in eight different proposals ( ), one for each iterations. SMS boundaryLast chance to change next SMS Requirement to have Iteration #6 in the last SMS

18 September 8, 2008 ACS-R PSR Documentation

19 September 8, 2008 ACS-R PSR Software development Most of the software needed during the optimization campaign was already developed to support the SM4 FT and TV testing. Two additional codes needed to be developed to address the need to monitor relative changes in CTE and Cross Talk using hot pixels and cosmic rays in dark frames.  The algorithms has been developed and the software has been tested on pre-failure dataset We are now working on putting all software together in a pseudo-pipeline we will maintain high level of hands-on activity for quality control purposes. We are also defining how we will report results from each test to DCL/Teledyne

20 September 8, 2008 ACS-R PSR Cross talk analysis Cross talk analysis from hot pixels in 16 on-orbit dark frames.

21 September 8, 2008 ACS-R PSR CTE from hot pixels The analysis of the tail of bright pixel is a fairly sensitive tool to measure relative changes in parallel and serial CTE.

22 September 8, 2008 ACS-R PSR STScI-STAFFING Oversight, report and contact point for DCL/Teledyne and SMOV team  Marco Sirianni  Ron Gilliland  Linda Smith (SMOV Lead) Scientist for data analysis  David Golimowski  Norman Grogin (CTE-internal, Cross talk)  Marco Chiaberge (CTE – external)  Anatoly Suchkov (Cross-talk) Research Instrument Analyst and Research Instrument Scientist for data analysis  Pey-Lian Lim  Tyler Desjardins  Max Mutchler  Ray Lucas We plan to cover 24/7 most of the 3-week period with a team which will include at least one person from each group

23 September 8, 2008 ACS-R PSR Decision points These are the main decision points we will need to pass during the first few weeks of SMOV (approximate dates for an October 8 launch)  TBD (after the SM4 FT) Two-detector mode  10/21 FPGA data transfer rate  10/26 (after analysis of the data of the first iteration) - Execution of optimization campaign (decision matrix in next page) - Change of default CDS for optimization campaign  10/28 Changes to 2 nd week of optimization campaign  11/4 Changes/removal of 3 rd week of optimization campaign  TBD End of optimization campaign - Clamp and Sample vs Dual slope for SMOV and Science - Decision based on overall performance

24 September 8, 2008 ACS-R PSR ACS-R Team (part of) “Evil” Ed Pete Beky Kevin

25 September 8, 2008 ACS-R PSR Yes, ACS-R is ready STScI has had a “monitoring/consulting” role for most of the ACS-R development. Many commands have been changed/developed, many inputs have been given for the planning of the optimization campaign. STScI is responsible for the implementation and the majority of the data analysis taken during the the optimization campaign. We would be not ready without the hard work, skills and dedication (and patience) of:  Alan Welty  Anatoly Suchkov  Denise Taylor  George Chapman  Ilana Dashevsky  Merle Reinhart  Tom Walker  Tom Wheeler  Tracy Ellis  And the entire AWT team and many, many other at STScI. THANKS !