ACS-R Readiness Status Marco Sirianni TIPS - September 18 2008

1. ACS-R Readiness StatusMarco SirianniTIPS - September 18 2008

2. 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 ACS-R PSR

3. 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 2nd 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 3rd 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. ACS-R PSR

4. ASC-R Hardware Images CEB-R FM-1 POE Harness LVPS-R FM-1 PIE Harness FM-2 Fitcheck ACS-R PSR

5. Thermal Vacuum Test Summary & Milestones • Test conducted at GSFC in Chamber 238 • Hot operate balance • 8/12/2008 @ 1900 EDT • Cold operate balance: • 8/13/2008 @ 1000 EDT • Cold protoflight “balance”: • 8/14/2008 @ 0715 EDT • Hot protoflight “balance”: • 8/15/2008 @ 0730 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: 441.2 hours Side B: 63.4 hours • 100.9 hot protoflight hours • 25.7 hot protoflight hours • 101.2 cold protoflight hours • 14.6 cold protoflight hours • Test duration from chamber close to test completion • 667.3 hours or 27.8 days • Functionals and performance tests successfully executed at plateaus • Generated over 700 WFC CEB-R images for ACS Science Team ACS-R PSR

6. Thermal Vacuum Test As-Run Profile ACS-R PSR

7. Expected Noise performance • 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 ACS-R PSR ACS-R PER 7

8. Crosstalk Meets Specification Crosstalk for the clamp-and-sample video processing chain meets specification of 1 part in 60000. (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. ACS-R PSR ACS-R PER 8

9. Bias Drift ACS-R PSR ACS-R PSR • 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

10. 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) ACS-R PSR

11. Bias Stability—Level of effect Clamp & Sample Dual Slope Integrator ACS-R PSR

12. Other items under investigations ACS-R PSR ACS-R PSR 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 0.0012% • No indications of this problem have ever been seen during the hundreds of hours on the CEB-R EMs or FMs 13

13. Optimization Campaign ACS-R PSR ACS-R PSR • 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

14. Optimization Campaign Highlights ACS-R PSR ACS-R PSR • 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

15. Operating Mode Decisions ACS-R PSR ACS-R PSR • 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

16. Optimization Campaign • The optimization program has been implemented in eight different proposals (11809-11816), one for each iterations. SMS boundary Last chance to change next SMS Requirement to have Iteration #6 in the last SMS ACS-R PSR

17. Documentation ACS-R PSR

18. 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 ACS-R PSR

19. Cross talk analysis Cross talk analysis from hot pixels in 16 on-orbit dark frames. ACS-R PSR

20. 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. ACS-R PSR

21. 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 ACS-R PSR

22. 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 2nd week of optimization campaign • 11/4 Changes/removal of 3rd week of optimization campaign • TBD End of optimization campaign • Clamp and Sample vs Dual slope for SMOV and Science • Decision based on overall performance ACS-R PSR

23. ACS-R Team (part of) Kevin Pete Beky “Evil” Ed ACS-R PSR

24. 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 ! ACS-R PSR