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

ACS-R Readiness StatusMarco Sirianni

TIPS - September 18 2008

2 September 8, 2008ACS-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


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.


ASC-R Hardware Images

CEB-R FM-1

LVPS-R FM-1

FM-2 Fitcheck

POE Harness

PIE Harness


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


Thermal Vacuum Test As-Run Profile

Ambient

Thermal Cycle # 1 2 3 4 5 6 7

Configured With Loop Back system

8

CEB-R Chassis Temperature

Power OFF

Key:

9 10 11

TEST ACTIVITIES

12

CEB-R + LVPS-R TVAC Test Profile (AS-RUN)

1 2 3

4

10 C

-5 C

-35 C

30 C

60 C

40 C

5 6

7

8

9

10

11

12

13

14 15

1

16

Configured With ACS-5 Detector

Safe-to-mate, install loopback cables, perform Ambient temp and pressure Functional -- Side A and B

-40 C

LVPS-R Temperature

2 Close chamber, pump down

3 Ambient temp, chamber pressure at < 1.0E-05 Torr – functional side A and B

4

Thermal Balance, Hot operate – Side A running

5

Thermal Balance, Cold operate – Side A running

6

Power off, dwell at cold survival

7

Cold start – side A, power off, cold start side B

8

9

Protoflight, Hot Op 1 – functional – CEB-R side B, LVPS-R side B

-30 C

10

11

12

13

14

15

16

17

18

19

17

19

21 23 25 27

18

20 22 24 26 28 30

31

32

3329

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34 35

Protoflight, Cold Op 2 – functional – CEB-R side A, LVPS-R side A

Protoflight, Cold Op 1 – functional – CEB-R side B, LVPS-R side B

Protoflight, Hot Op 2 – functional – CEB-R side A, LVPS-R side A

Protoflight, Cold Op 3– functional – CEB-R side A, LVPS-R side A


Protoflight, Cold Op 4 – functional – CEB-R side A, LVPS-R side A



Protoflight, Cold Op 5 –functional – CEB-R side A , LVPS-R side A

Protoflight, Hot Op 6 – performance – CEB-R side B, LVPS-R side B

Protoflight, Cold Op 6 –performance – CEB-R side A, LVPS-R side A

Protoflight, Hot Op 7 – performance – CEB-R side A, LVPS-R side A


Protoflight, Hot Op 8 – performance – CEB-R side A, LVPS-R side A


Protoflight, Hot Op 9 – performance – CEB-R & LVPS-R side A

Protoflight, Cold Op 9 –performance – CEB-R & LVPS-R side A







Power off, dwell for Hot Survival

34

Dwell for contamination cert

35

Power on, ambient performance – CEB-R & LVPS-R side A + B

36

36 38

37

Bleed up chamber

LVPS-R/CEB-R Side A

LVPS-R/CEB-R Side B

Ramp to ambient, power off CEB and test set, bleed up chamber

Ambient Functional CEB-R side A, LVPS-R side A,

Disconnect loopback cables, perform safe to mate, connect ACS-5 detector

Ambient performance test CEB-R / LVPS-R side A and side B, pump down

38

39

40

BUS Voltage

42

43

39

24 V

28 V

32 V

41

4040

42

43

Cold start – side B, power off, cold start side A

Hot start – side A, power off

Ramp to ambient, bleed up, install kapton tent, pump down

Dwell for contamination bake out

37

40

41

7 September 8, 2008ACS-R PSR 7ACS-R PER

Expected Noise performance

A (e-) B(e-) C(e-) D(e-)

Pre-failure 5.6 4.7 5.2 4.8

Predicted (DSINT)

4.4 3.6 4.0 3.9

Predicted (CLAMP)

4.2 3.8 4.2 4.2

•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 readnoiseperformance

8 September 8, 2008ACS-R PSR 8ACS-R PER

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.


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.

9ACS-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)


Bias Stability—Level of effect

Clamp & Sample Dual Slope Integrator


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 0.0012%

- No indications of this problem have ever been seen during the hundreds of hours on the CEB-R EMs or FMs

13ACS-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.

14ACS-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.

15ACS-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.

16ACS-R PSR


Optimization Campaign

• The optimization program has been implemented in eight different proposals (11809-11816), one for each iterations.

SMS boundary Last chanceto change next SMS

Requirement to haveIteration #6 in the last

SMS


Documentation


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


Cross talk analysis

Cross talk analysis from hot pixels in

16 on-orbit dark frames.


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.


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


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 Team (part of)

“Evil” Ed

PeteBeky

Kevin


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 !

Documents

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