TIPS/JIM
November 18, 2010
Agenda:
INS Division News (Danny Lennon)
MIRI Observing Templates (Christine Chen)
Non-redundant Tilts (NRT) – A Fallback Coarse Phasing Method for
JWST Using TFI (Anand Sivaramakrishnan)
JWST Integration and Testing – The Testing Assessment Team Review
(Erin Elliott)
Next TIPS/JIM: December 16, 2010
INS News Nov 18th 2010
----------------------
New INS arrivals:
----------------Klaus Pontoppidan Instrument Scientist, WIT
Sara Ogaz RIAB
Justin Ely RIAB
Peter McCullough Instrument Scientist, WFC3 (from sabbatical)
Marshall Perrin, TEL/OTA
Departures from INS:
-------------------Jerry Kriss to sabbatical
Francesca Boffi to IT Project Scientist
Jason Kalirai to JWST Dep. Proj. Scientist
Changes in INS:
--------------Diane Karakla to Interim RIAB lead
Margaret Meixner to Deputy Head INS (from WIT/sabbatical)
Danny Lennon to Head of INS from Deputy
DCRWG changes and news:
----------------------Margaret Meixner to coordinate for INS
New members:
Susana Deustua
Pierre Chayer
Erin Elliot
Annie Valenzuela
Depashri Thatte
Members rotating off:
Aparna Maybhate
Misty Cracraft
Tracy Beck
Rossy Diaz (outgoing chair)
Continuing:
Remi Soumer (new chair)
David Soderblom
Marco Chiaberge
Other news:
---------The ICRP report on JWST has been published and we have added to the agenda a
short presentation on this by Margaret Meixner. TIPS/JIM
November 18, 2010
Agenda:
INS Division News (Danny Lennon)
MIRI Observing Templates (Christine Chen)
Non-redundant Tilts (NRT) – A Fallback Coarse Phasing Method for
JWST Using TFI (Anand Sivaramakrishnan)
JWST Integration and Testing – The Testing Assessment Team Review
(Erin Elliott)
Next TIPS/JIM: December 16, 2010
MIRI Observing Templates
•
MIRI is a NASA/JPL-led partnership
with a European Consortium sponsored
by ESA
–  NASA provides focal planes, signal chain
–  Consortium provides optical bench
assembly
Science team
George Rieke (U of A, Lead)
Gillian Wright (ROE, Instrument PI
and Co-lead)
Tom Greene (NASA-Ames)
Margaret Meixner (STScI)
Mike Ressler (NASA-JPL, Instrument
Scientist)
Torsten Boeker (ESA-ESTEC)
Thomas Henning (MPIA)
Luis Colina (CSIC-IEM)
STScI Instrument team
Christine Chen (APT/ETC)
Scott Friedman (Commissioning)
Karl Gordon (Calibration)
Dean Hines (Operations)
Rachel Anderson
Misty Cracraft
8/1/10
C. H. Chen
1/18
MIRI Operating Configurations
•  Imaging
–  λ = 5 - 27 µm wavelength range
–  Diffraction limited imaging with 0.11” pixels
–  ~2 square arcmin field of view
•  Coronagraphy
–  Three 4 Quadrant Phase Masks (10.65, 11.4, and 15.5 µm)
–  One Lyot Coronagraph (23 µm)
•  Low Resolution Spectroscopy (LRS)
–  R ~ 100 from λ = 5 - 10 µm
•  Medium Resolution Spectroscopy (MRS)
–  λ = 5 - 27 µm wavelength range, goal to reach λ = 28.3 µm
–  Integral field spectroscopy with fields of view of 3” or more
–  R ~ 3000 - 1000 from λ = 5 - 27 µm
8/1/10
C. H. Chen
2/18
MIRI FOV on the Sky
•
For more information, see “Mid-infrared Instrument (MIRI) Operations Concept
Document” Rev C edited by C. H. Chen JWST-STScI-00910
8/1/10
C. H. Chen
3/18
MIRI Data Format
Nominal Data File Coordinates
(w/Ref Output)
Nominal Data File Coordinates
In Final Format
•  Reference Pixels - four pixels at the beginning and end of each row
with no light sensitivity, one for each data output
•  Reference Output pixels - “blind” pixels interleaved with light-sensitive
pixels that use a separate data output
8/1/10
C. H. Chen
4/18
MIRI Readout Patterns
•  FASTMode
–  Each pixel in the (sub-)array is sampled once and that value is
returned
–  Full frame time 2.775 sec
–  Will be used to observe bright targets
•  SLOWMode
–  Each pixel in the (sub-)array is sampled 10 times, the middle 8
samples are averaged together and returned
–  Full frame time 27.75 sec
–  Will be used to observe faint targets
8/1/10
C. H. Chen
5/18
Imaging Astronomical Observation Requests
•  Target acquisition
–  Current implementation does not include target acquisition for direct imaging
–  The smallest subarrays (SUB64 and SUB128) may require target acquisition
–  User will specify TA source coordinates, TA filter, and expected brightness for
the TA source in TA filter
•  Filter
–  User will select based on the science justification
•  Subarray
–  User will select based on the science justification and the brightness of the target,
with guidance from ETC/APT software
•  Readout Pattern
–  User will select based on the science justification and the brightness of the target
with guidence from ETC/APT software
•  Dither Pattern
–  User will select based on science justification
8/1/10
C. H. Chen
6/18
Imaging: Filter Selection
Filter name
center
wavelength,
0
F560W
F770W
F1000W
F1130W
F1280W
F1500W
F1800W
F2100W
F2550W
F2550WR
FND
FLENS
OPAQUE
8/1/10
filter
bandpass,
Comment
( m)
5.6
7.7
10
11.3
12.8
15
18
21
25.5
25.5
( m)
1.2
2.2
2.0
0.7
2.4
3.0
3.0
5.0
4.0
4.0
13
10
N/A
blackened
blank
N/A
broad band
PAH, broad band
Silicate, broad band
PAH, broad band
Broad band
Broad band
Silicate, broad band
broad band
broad band
redundant filter, risk reduction
for coron. acquis.
reduction ~ 2×10-3
testing
N/A
for darks
C. H. Chen
7/18
Imaging: Subarray Selection
SUBARRAY
ROWS
COLUMN
S
FIRST ROW
CORNER
FIRST COL
CORNER
FULL
MASK1065
MASK1140
MASK1550
MASKLYOT
BRIGHTSKY
SUB256
SUB128
SUB64
SLITLESSPRI
SM
1024
256
256
256
320
512
256
128
64
512
1032
256
256
256
320
864
608
132
68
68
1
1
229
452
705
1
1
897
897
348
1
1
1
1
1
1
1
1
1
1
•
8/1/10
LIGHT
SENSITIVE
COLUMNS
1024
224
224
224
275
512
256
128
64
64
For more information, see “MIRI Subarrays for
Planetary Transits and Other Bright Objects” Rev.
A by C. H. Chen, G. H. Rieke, & K. D. Gordon,
JWST-STScI-001757
C. H. Chen
8/18
Imaging: Dither Pattern Selection
•
Available Patterns
–
–
–
–
No Dither (for transiting extra-solar planets)
5-Point Gaussian (SUB64, SUB128)
12-Point Reauleaux (SUB256, BRIGHTSKY, or FULL array)
311-Point Cycling Pattern (SUB256, BRIGHTSKY, or FULL array)
•
•
•
•
User specifies starting position in list of offsets and number of dither positions required
Available Pattern Sizes: S, M, L
Optimal pattern sizes exist based on the
For more information, see “MIRI Imaging Dither Patterns” Rev A by C. H Chen JWSTSTScI-001657
8/1/10
C. H. Chen
9/18
Coronagraphic Astronomical Observation Requests
•  Target acquisition
–  User will specify TA source coordinates, TA filter, and expected brightness for
the TA source in TA filter
–  For more information, see “Mid-Infrared Instrument (MIRI) Target Acquisition
Strategies and Use Cases” by Gordon & Meixner, 2008, JWST-001407
•  Coronagraph/Filter
–  User will select based on the science justification
•  Subarray
–  Will be automatically selected based on Coronagraph/Filter selection
•  Readout Pattern
–  User will select based on the science justification and the brightness of the target
with guidance from ETC/APT software
•  Dither Pattern
–  No dither pattern is allowed
8/1/10
C. H. Chen
10/18
Coronagraph: Coronagraph/Filter Selection
4QPM
Lyot
•  User must select which of the following coronagraphs they would like to
use: 4QPM at 10.65, 11.4, or 15.5 µm or Lyot Coronagraph at 23 µm
8/1/10
C. H. Chen
11/18
LRS Astronomical Observation Requests
•
Target acquisition
–  User will specify TA source coordinates, TA filter, and expected brightness for the TA
source in TA filter
–  For more information, see “Mid-Infrared Instrument (MIRI) Low Resolution Target
Acquisition for Faint Sources” by Gordon, 2008, JWST-STScI-001347
•
Filter
–  Is automatically set to “LRS Prism”
•
Subarray
–  User will select (either LRS-Slit or LRS-Slitless) based on the science justification and the
brightness of the target, with guidance from ETC/APT software
•
Readout Pattern
–  User will select based on the science justification and the brightness of the target given
guidance from ETC/APT software
•
Dither Pattern
–  If LRS-Slit, then user will select based on science justification
8/1/10
C. H. Chen
12/18
LRS Slit vs LRS Slitless Observations
Slitless
Slit
Target placed
in the slit
•
Target placed
in the Lyot
FOV
LRS Slit
–  LRS Slit Target Acquisition
–  FULL frame is readout
•
LRS Slitless
–  LRS Slitless Target Acquisition TBD
–  SLITLESSPRISM subarray is readout
8/1/10
C. H. Chen
13/18
LRS Slit Observations: Dither Pattern Selection
•
Point Source/Staring
–  Always two positions in the slit
–  Always 1/3 and 2/3 of the way along the slit
•
Extended Source/Mapping
–  Customizable grid of positions
–  User gives number of positions parallel and perpendicular to the slit
–  User gives offset between slit positions in direction parallel and perpendicular to the
slit
•
For more information, see “The LRS Dither Pattern ” by C. H. Chen JWSTSTScI-001634
8/1/10
C. H. Chen
14/18
MRS Astronomical Observation Requests
•  Target acquisition
–  User will specify TA source coordinates, TA filter, and expected brightness for
the TA source in TA filter
–  For more information, see “Mid-Infrared Instrument (MIRI) Target Acquisition
Strategies and Use Cases” by Gordon & Meixner, 2008, JWST-001407
•  Grating
–  User will select based on the science justification
•  Subarray
–  Only FULL array observations are allowed
•  Readout Pattern
–  User will select based on the science justification and the brightness of the target
with guidance from ETC/APT software
•  Dither Pattern
–  User will select based on science justification
8/1/10
C. H. Chen
15/18
MRS Overview
10 arcseconds
Each channel’s field of view is
sliced, dispersed and detected.
Channel 1
(4.9 - 7.7 µm)
Channel 2
(7.4 - 11.8 µm)
Channel 3
(11.4 - 18.2 µm)
Channel 4
(17.5 - 28.8 µm)
8/1/10
Wavelength/Velocity
C. H. Chen
16/18
MRS: Grating Selection
FOV Name
-range
( m)
Channel 1
4.86 7.74
FOV (″×″)
3.7 × 3.7
Channel 2
7.43 11.84
4.5 × 4.7
Channel 3
11.44 18.20
6.1 × 6.2
Channel 4
17.53 28.75
7.7 × 7.7
sub-band
name
ra n g e
( m)
resolution
A
B
C
A
B
C
A
B
C
A
B
C
4.87 5.82
5.62
6.49 7.76
7.45 8.90
8.61 10.28
9.94 11.87
11.47 13.67
13.25 15.80
15.30 18.24
17.54 21.10
20.44 24.72
23.84 28.82
2450
2450
2450
2480
2480
2480
2510
2510
2510
2070
2070
2070
3710
3710
3710
3690
3690
3690
3730
3730
3730
2490
2490
2490
•  Select one sub-band at a time
(A-”short”,B-”medium”, or C-”long”) or ALL
8/1/10
C. H. Chen
17/18
MRS: Dither Pattern Selection (TBD)
Pattern 2
Pattern 1
•
•
•
Pattern 1 - improved spatial sampling for all channels simultaneously
Pattern 2 - improved spatial and spectra sampling for one channel at a time (Ch
1, 2, 3, and 4 optimized patterns)
For more information, see “MIRI MRS Dither Patterns” by C. H. Chen & A.
Glasse JWST-STScI-001871
8/1/10
C. H. Chen
18/18
TIPS/JIM
November 18, 2010
Agenda:
INS Division News (Danny Lennon)
MIRI Observing Templates (Christine Chen)
Non-redundant Tilts (NRT) – A Fallback Coarse Phasing Method for
JWST Using TFI (Anand Sivaramakrishnan)
JWST Integration and Testing – The Testing Assessment Team Review
(Erin Elliott)
Next TIPS/JIM: December 16, 2010
Coarse phasing JWST using NonRedundant Tilts (NRT) in TFI
a back-up method requiring no extra hardware
Anand Sivaramakrishnan
JWST TFI Science Team (NRM lead)
JAM team lead
Stony Brook University Physics & Astronomy Department
Peter G. Tuthill
University of Sydney & JAM Team
D. Scott Acton
Ball Aerospace
STScI TIPS JIM November 18 2010
1 JWST Commissioning
2 Exit gate: no segment deviates in piston from
the mean piston of all segments by >~ 300nm
Baseline method: Dispersed
Hartmann Sensing
• Well-understood
• Works well on WFSC testbed
• Two of them in 2 NIRCams
• STScI expert Erin Elliott
• Looks good
3 Why develop back-up?
• Comfort
• Uses different instrument than NIRCam SW
• Flexible diagnostic tool, mitigate risks
• No new hardware required
• Look at the NRT idea for show-stoppers
4 Image Stacking before
Coarse Phasing
• segment images must be moved to fall at a common
location on one of the NIRCam SCA’s - “Stack Center”
• Large moves inaccurate, small moves accurate (details
ITAR)
5 Groups of three segments
6 Groups of four segments
7 NRT PSF
8 Spectral Bandwidth
9 Filters
Capture range
Λ = λχ/β = R.λ
TFI R=100 4-5um
NIRCam LW
R=100 4 filters
2nπ ambiguity:
3 wavelengths 10 TIPS/JIM
November 18, 2010
Agenda:
INS Division News (Danny Lennon)
MIRI Observing Templates (Christine Chen)
Non-redundant Tilts (NRT) – A Fallback Coarse Phasing Method for
JWST Using TFI (Anand Sivaramakrishnan)
JWST Integration and Testing – The Testing Assessment Team Review
(Erin Elliott)
Next TIPS/JIM: December 16, 2010
Results from the JWST Testing Assessment Team
Review
Erin Elliott
18 November 2010
Context
• Testing Assessment Team (TAT) was tasked by NASA HQ to
review JWST’s integration and test plans.
• Prompted by a request for review from Senator Mikulski.
• Members:
John Casani, Chair, Jet Propulsion Laboratory
Alan Dressler, Carnegie Observatories
Matt Mountain, Space Telescope Science Institute
Jerry Nelson, University of California–Lick
Observatory
Jim Oschmann, Ball Aerospace
Al Sherman, Allan Sherman, LLC
Georg Siebes, Jet Propulsion Laboratory
Erick Young, USRA
Bill Irace, Jet Propulsion Laboratory
Milt Heflin, NASA Johnson Space Center
Jeff Kegley, NASA Marshall Space Flight Center
Mike Ryschkewitsch, NASA
• Review focused on:
– ISIM testing at GSFC
– OTIS testing at JSC (OTIS = OTE + ISIM)
November 18, 2010
2
JWST Architecture
November 18, 2010
3
Overview of JWST I&T
November 18, 2010
4
ISIM Testing Overview
• ISIM testing uses an OTE
simulator (OSIM)
• Each cryo cycle takes 20 weeks
(7 wks of cooldown & warmup)
• Thermal tests include
– Measurement of total load
ISIM puts on cryocooler
– Measurement of ISIM
radiators and straps
• Optical tests include
– SI to ISIM pupil shear and
focus
– SI wavefront errors
– Data needed for ISIM to
AOS alignment
– Plate scale measurements
– WFSC calibrations
November 18, 2010
5
OTIS Testing
November 18, 2010
6
OTIS Testing
• Single cryo cycle planned, taking
170 days.
• Cost is about $1,000,000 per day!
• Thermal tests include:
– OTE temperature
– Core isolation performance
– ISIM electronics compartment
isolation performance
– ISIM & line loads
Optical tests include:
• Primary / secondary alignment to the AOS
• Primary / secondary actuator ranges
• ISIM to AOS alignment
• Final plate scales
• Primary mirror ROC, conic, astigmatism, tilt
• Closed-loop WFSC demonstration
• Rogue, truant path checks
November 18, 2010
Cryo Position
Metrology
Primary Mirror LF
WFE & Stability
SM
PG
PG
AOS
PG
PG
PM
7
TAT Conclusions
The TAT Team concluded that the ISIM testing at GSFC can be
reduced from 14 months to 10 months and believes the OTIS
testing at JSC can be reduced from 167 days to 90 days with
acceptable reduction in pre-launch predictability of performance
and without predictable loss of science capability. This reduction
could shorten the critical path, avoiding significant cost growth.
November 18, 2010
8
TAT Recs – Science & Testing Priorities
• Prioritize key system requirements, and design and implement the
test program using those priorities.
• Conclude OTIS testing in 90 days. Continued work is only justified by
substantial risk to Level 1 science requirements.
• Prioritize functional tests over performance tests. Complete functional
tests early in the test sequence.
• There is a range of test temperatures in which all instruments but
MIRI can be verified. MIRI verification should not drive a second OTIS
cycle nor prolong the first test cycle.
– Test plan should be driven by NIRCam, FGS, and NIRSpec.
• Test all detectors at temperatures up to at least 60 K.
– NIRSpec data wasn’t taken at the time.
• Make an effort to obtain new NIRSpec flight detectors with improved
dark-current performance.
– Observatory could operate over wider range of on-orbit temps.
November 18, 2010
9
TAT Recs – Organization and Decision Making
• Establish an I&T Lead responsible for defining and documenting a
clear I&T approach.
• Adopt overall I&T plan that maximizes efficiencies over the entire
test program. Goal is to minimize risk of cost and schedule growth
during OTIS testing.
– High risk of needing a second cryo cycle at OTIS.
• Develop decision criteria and contingency plans for OTIS testing.
• Employ a command-and-decision structure during OTIS testing
similar to the one used for the Hubble Servicing Missions.
• Assess implications of proposed SE reorg. Make sure GSFC has the
necessary staff to support it.
November 18, 2010
10
TAT Recs – Optical Testing
• Priorities at JSC should be:
– Mechanism tests
– Photogrammetric optical alignment
– AOS to ISIM alignment
– Verification of integrated FSM/ FGS functionality
– COC testing of the primary mirror
• Establish clear pass/fail criteria. Put cross-checks and
extrapolations to on-orbit performance as optional tests.
• Eliminate cryo frill and rogue-path tests and reduce the scope of
the pass-and-a-half testing.
• Eliminate CPT testing at the ISIM and OTIS levels. Do at SI level.
• Reduce WFSC demonstrations, concentrating on functional testing
and polarity checks.
• Increase concurrent optical and thermal testing during ISIM testing.
November 18, 2010
11
TAT Recs – Thermal Testing
• Combine the two thermal balance points in the OTIS testing to a single
test.
– Add a core test, updated to the current flight design.
– Add thermal testing to the Pathfinder testing.
• Eliminate the first ISIM cryo test.
– Add a cryo test with OSIM and the NIRCam ETU (off the critical
path).
– Measure SI displacements during proof-load testing.
• Postpone installation of OTIS GSE until after chamber commissioning.
• Shorten thermal model turnaround times to a few hours.
– Prevents costly delays during OTIS testing.
• Develop tiered criteria that permit progressive assessments based on
information as it evolves, and reduce test time where possible.
• Increase parallel optical and thermal testing during OTIS testing.
• Apply available radiator margin to reduce stabilization times.
November 18, 2010
12
How do we build and test larger missions?
• Interesting higher-level discussion during TAT proceedings.
• “Test as you fly” is a well-established NASA rule.
– Waivers required when testing doesn’t meet the requirement.
• JWST already in the regime where that is not possible.
– OTIS testing takes place with a sunshield and spacecraft
simulator.
• Electrical connections, etc., made after OTIS testing won’t be
performance-tested at cryo.
– A return flat isn’t available for a full-aperture end-to-end optical
test.
• Three small flats are used instead.
– The JSC chamber doesn’t recreate the flight thermal
environment.
• Clearly can’t build larger chambers and test mirrors as the collecting
areas increase.
• How do we build systems in pieces and guarantee that the system
will work correctly after assembly?
November 18, 2010
13
How do we ensure thermal performance in
JWST and larger missions?
• Two schools of thought on thermal testing:
1. Test in a very flight-like environment.
–
Thermal models used during design stage only.
2. Accept testing in a non-flight-like environment and use thermal models to predict on-orbit
performance.
•
•
•
•
JWST uses approach # 2.
–
Facility large enough to create a flight-like environment doesn’t exist.
–
JWST is passively cooled. Error in thermal design could equal lost mission, not just a
shorter mission lifetime.
–
Accuracy and turnaround times for the thermal models is a constant struggle.
–
Thermal balance tests are very time-consuming and $.
Several NASA missions launched recently are running warmer than predicted. These are
actively cooled missions, so leads to shorter mission lifetimes.
There is a need to review the missions as a group to look for common issues.
But also: How do we make systems more robust w.r.t. operating in varying thermal
environments?
–
Part of the answer is to pursue detectors with improved dark current vs. T
performance.
November 18, 2010
14