ACS-R Readiness Status
Marco Sirianni
TIPS - September 18 2008
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
2
September 8, 2008
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
3
September 8, 2008
ASC-R Hardware Images
CEB-R FM-1
POE
Harness
LVPS-R FM-1
PIE
Harness
FM-2 Fitcheck
ACS-R PSR
4
September 8, 2008
Thermal Vacuum Test
Summary & Milestones
•
Test conducted at GSFC in Chamber 238
•
Thermal cycling comprised of:
 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
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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:
•
Test duration from chamber close to test completion
•
Functionals and performance tests successfully executed at plateaus
 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
 667.3 hours or 27.8 days
 Generated over 700 WFC CEB-R images for ACS Science Team
ACS-R PSR
5
September 8, 2008
Thermal Vacuum Test
As-Run Profile
Key:
CEB-R + LVPS-R TVAC Test Profile (AS-RUN)
CEB-R Chassis Temperature
LVPS-R Temperature
Power OFF
Configured With Loop Back system
Configured With ACS-5 Detector
9
7
11
13
21
60 C
23
25
27
31
29
33
36
38
40
37
41
40 C
18
30 C
Ambient
42
1
2
3
14 15
16
17
43
39
19
10 C
-5 C
-30 C
40
-35 C
4
5
8
6
10
12
20
22
24
26
28
32
30
35
34
-40 C
Thermal Cycle #
1
2
3
4
6
5
7
8
9
10
11
12
LVPS-R/CEB-R Side A
LVPS-R/CEB-R Side B
32 V
BUS Voltage
28 V
24 V
TEST ACTIVITIES
Safe-to-mate, install loopback cables, perform Ambient temp and pressure
Functional -- Side A and B
2 Close chamber, pump down
1
Protoflight, Cold Op 10 –performance – CEB-R & LVPS-R side A
15
Ambient Functional CEB-R side A, LVPS-R side A,
16
Disconnect loopback cables, perform safe to mate, connect ACS-5 detector 31
Protoflight, Hot Op 10 – performance – CEB-R & LVPS-R side A
17
Ambient performance test CEB-R / LVPS-R side A and side B, pump down
32
Protoflight, Cold Op 11 –performance – CEB-R & LVPS-R side A
Protoflight, Hot Op 11 – performance – CEB-R & LVPS-R side A
30
3
Ambient temp, chamber pressure at < 1.0E-05 Torr – functional side A and B
18
Thermal Balance, Hot operate – Side A running
33
4
Power off, dwell at cold survival
19
Thermal Balance, Cold operate – Side A running
34
Protoflight, Cold Op 12 –performance – CEB-R & LVPS-R side A
5
Cold start – side A, power off, cold start side B
20
Protoflight, Cold Op 5 –functional – CEB-R side A , LVPS-R side A
35
Cold start – side B, power off, cold start side A
6
Protoflight, Cold Op 1 – functional – CEB-R side B, LVPS-R side B
21
Protoflight, Hot Op 12 – performance – CEB-R & LVPS-R side A
Protoflight, Hot Op 1 – functional – CEB-R side B, LVPS-R side B
22
Protoflight, Hot Op 5 – functional – CEB-R side A, LVPS-R side A
Protoflight, Cold Op 6 –performance – CEB-R side A, LVPS-R side A
36
7
37
8
Protoflight, Cold Op 2 – functional – CEB-R side A, LVPS-R side A
23
Protoflight, Hot Op 6 – performance – CEB-R side B, LVPS-R side B
38
Power off, dwell for Hot Survival
Hot start – side A, power off
Protoflight, Hot Op 2 – functional – CEB-R side A, LVPS-R side A
24
Protoflight, Cold Op 7 –performance – CEB-R side A, LVPS-R side A
39
Ramp to ambient, bleed up, install kapton tent, pump down
10 Protoflight, Cold Op 3– functional – CEB-R side A, LVPS-R side A
25
40
Dwell for contamination bake out
Protoflight, Hot Op 3 – functional – CEB-R side A, LVPS-R side A
26
Protoflight, Hot Op 7 – performance – CEB-R side A, LVPS-R side A
Protoflight, Cold Op 8 –performance – CEB-R side A, LVPS-R side A
41
Dwell for contamination cert
12
Protoflight, Cold Op 4 – functional – CEB-R side A, LVPS-R side A
27
Protoflight, Hot Op 8 – performance – CEB-R side A, LVPS-R side A
42
Bleed up chamber
13
Protoflight, Hot Op 4 – functional – CEB-R side A, LVPS-R side A
Ramp to ambient, power off CEB and test set, bleed up chamber
28
Protoflight, Cold Op 9 –performance – CEB-R & LVPS-R side A
43
Power on, ambient performance – CEB-R & LVPS-R side A + B
29
Protoflight, Hot Op 9 – performance – CEB-R & LVPS-R side A
9
11
14
ACS-R PSR
6
September 8, 2008
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
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
•ACS-R is expected to meet and possibly improve pre-failure readnoise
performance
ACS-R PER
PSR
7
September 8, 2008
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 PER
PSR
8
September 8, 2008
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.
ACS-R PSR
9
September 8, 2008
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)
ACS-R PSR
Residual (10x observed error)
11
September 8, 2008
Bias Stability—Level of effect
Clamp & Sample
ACS-R PSR
Dual Slope Integrator
12
September 8, 2008
Other items under investigations
Minor anomalies have been detected and will be corrected in software with no performance impact.

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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
ACS-R PSR
13
September 8, 2008
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.
ACS-R PSR
14
September 8, 2008
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.
ACS-R PSR
15
September 8, 2008
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.
ACS-R PSR
16
September 8, 2008
Optimization Campaign
•
The optimization program has been implemented in eight different
proposals (11809-11816), one for each iterations.
SMS boundary
ACS-R PSR
Last chance
to change next SMS
17
Requirement to have
Iteration #6 in the last
September 8, 2008
SMS
Documentation
ACS-R PSR
18
September 8, 2008
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
September 8, 2008
Cross talk analysis
Cross talk analysis from hot pixels in
16 on-orbit dark frames.
ACS-R PSR
20
September 8, 2008
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
September 8, 2008
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

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•
Research Instrument Analyst and Research Instrument Scientist for data
analysis

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
•
David Golimowski
Norman Grogin (CTE-internal, Cross talk)
Marco Chiaberge (CTE – external)
Anatoly Suchkov (Cross-talk)
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
September 8, 2008
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
September 8, 2008
ACS-R Team (part of)
Kevin
Pete
Beky
“Evil” Ed
ACS-R PSR
24
September 8, 2008
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:
•
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ACS-R PSR
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.
25
September 8, 2008