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Gillian Wright/John Thatcher - European ConsortiumGeorge Rieke – University of Arizona

Greg Goodson/Phillip Barela – Jet Propulsion LaboratoryScott Friedman – Space Telescope Science Institute

MIRI Optical System Status JWST PARTNERS WORKSHOP

October 2008

Some of the content in this document is proprietary information of the MIRI European Consortium members & JPL and shall be used and disclosed by the receiving Party and related entities, (e.g. contractors and subcontractors), only for the purposes of fulfilling the Party’s responsibilities under the JWST Project and shall not be disclosed or retransferred to any other entity without prior written permission of the document preparer.

The data/information of U.S. origin contained herein has been reviewed and approved for release on the basis that this document contains no U.S. export-controlled information.

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Introduction

• MIRI presentation is split into two – Optical System (this talk) and Cooler System (next talk)

• Highlights

• Science Team & Operations

• The MIRI VM Test Campaign– Test results, issues

• MIRI FM Status– Focal Plane System– Optical Sub-assemblies– Recent Issues in work

• Risks

• Conclusions

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Highlights

• Since the last partners workshop we have :

• Completed two cryo-test campaigns with the MIRI VM– These give great confidence in expected MIRI performance and our ability to

calibrate it.– Lessons learned have been applied to the flight design of the ICE and FPE

• Completed environmental qualification testing for the most of the hardware

– Wheel mechanism assemblies qualification tests complete after FM instrument is assembled

• Completed manufacture and assembly of the three flight focal plane modules

– One is ready for delivery, the other two in final stages of acceptance testing

• FM optical component manufacture almost complete and assembly of all the FM optical sub-assemblies has begun.

– Some FM Units are delivered and now being stored.

• Science Team and STScI have made great progress in defining key aspects of MIRI operations

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Here it is - an image of aJupiter-sized planet obtainedby tracking it orbiting a starand monitoring the change insignal as different sides face us.

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done

done

done

for JWST

A planet exploration time line proposed in the ExNPS RoadMap in 1996

• We are right on track!

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This Spitzer photometry taken during a planet transit across its star shows how we will get spectra of the absorption of star light by a planet atmosphere. With JWST we can take the full spectrum, not just the individual points.

measurements

fitted spectrum

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Science Team Activities

• Study of how to do planet transit observations, to support efforts to implement appropriate operations, understand systematic errors in spectroscopy

• Support of FM and FS detector selections

• Review of VM performance test plans

• Agreement on “standard” centering approach for all JWST coronagraphs

• Starting study of “bright” source observations

• Successful proposal for Spitzer time to link HST white dwarf calibration to MIRI (and other JWST instruments)

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Operations Progress

• STScI Workshop on planet transit observations, further efforts to implement appropriate operations

• Definition of science and engineering observing templates (used to specify all “normal” MIRI observations)

• Prototyped Astronomer’s Proposal Tool (APT) for MIRI imaging

• Study of dither patterns, including simulations of data with realistic point spread functions and a model of the detector behavior

• Publication of a comprehensive paper on absolute calibration across the JWST bands

• Developing calibration plan

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The MIRI VM Cryo-Test Campaign

• At last workshop we reported: successful assembly, first light results in the optical, alignment testing, warm functional testing with the MFSW

– VM is flight representative instrument in all key aspects– VM test campaign is about de-bugging and fixing the flight plans.

• i.e. there are no plans to modify the VM or MTS and re-do tests

• VM1 (December 07-February 08)– Functional check out (wire connectivity, system can be driven cold etc)– Basic instrument performance with a simple point source– Thermal balance test (blanket performance)

• VM2 (August –October 08)– Test how the MIRI Telescope Simulator works (used for flight verification)

learn how best to use it for calibration.– Follow up results from VM1– Brief on-board scripts checkout with hardware for STScI development team

• The MIRI science team made a prioritised list of MIRI performance aspects which the test data should allow investigation of.

– This guided and set the goals for all aspects of the performance testing

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MIRI Test and Calibration Team

• MIRI Cryo-testing is carried out by an integrated international team supported by ALL the MIRI partners

– i.e. all the EC institutes, STScI, JPL, GSFC, Arizona, Ames

• Team organisation and participation has been a great success of the test campaign

– Some 40 people in total contributed

– Mixture of experienced instrument scientists and people testing an infrared instrument for the first time.

• This is the team that will carry out the flight performance verification tests, ground calibration of the flight instrument, flight calibration, in orbit checkout etc.

• Results on next slide are all thanks to them !

• Sticking on the institute logos and flags is the airplane amusement activity

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MIRI Test and Calibration Team

• MIRI Cryo-testing is carried out by an integrated international team supported by ALL the MIRI partners

– i.e. all the EC countries, STScI, JPL, GSFC, Arizona, Ames, ESA

• Team organisation and participation has been a great success of the test campaign

– Some 40 people in total contributed– Mixture of experienced instrument scientists and people testing an infrared

instrument for the first time.

• This is the team that will carry out the flight performance verification tests, ground calibration of the flight instrument, flight calibration, in orbit checkout etc.

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VM1 Mid-Infrared Images

• VM image of a point source at 11.3um – matches well the optical model including detail of diffraction pattern.

• Taken together with ETM imager testing, these results show that the imager optics perform as expected.

– And we have the knowledge/confidence to use to confirm MTS performance

• Spectra at 5.7–6.7 & 8.7–10.3 microns• Illuminated by on-board flat-field source

and so demonstrates the calibration source works as intended

• The positions of the spectra on the detector and the degree of curvature match the optical models

• The fringes are typical of mid-IR spectra, and in detail match the spectral resolution and thickness of the detector.

• Background variation as a function of wavelength is also as expected, so no major scattered light problems

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VM2 Preparation – MTS & VM on Test Bench

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VM2 Results Overview

• The primary goal of the VM2 test campaign was to characterise the MTS performance and for the test team to learn how best to use it for flight

– Dry run test scripts – Test team organisation– Secondary goals were to add fidelity to Thermal Balance testing and to

look at MIRI performance in more detail• MTS generally performs very well

– Cryomechanisms all work– Etalons work and used to test spectrometer

• Calibration of etalons planned between now and FM testing– Illumination for flat field is very flat– Point sources are out of focus over some of FoV– Very dark – The blackbody functions very well with ~3mK stability – important for

calibration• Software / scripts for combined MTS and MIRI control all verified• All performance tests that were planned for MIRI completed

– Test methodology adapted to achieved MTS performance– We have not completed reduction and assessment of VM data and what is

presented is preliminary

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Example of test results: MTS Repeatability

• Test - MTS source moved ‘out and back’ 1 arcsecond in X (red points) and Y (blue points)

• Plot shows deviations from the mean centroid position and is within specification• ‘Bad’ pixel centroid data was also taken, for analysis using ‘peak-down’ algorithm

baselined for the coronagraph.

-0.15

-0.10

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-0.25 -0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

MTS X Motion [pixels]

MT

S Y

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tio

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pix

els

]

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Example test Result: MIRI Spectroscopy

• Channel 1B spectrum ( ~ 6.2 m) using MTS Etalon_1A (obsID 2647)

• Spectral resolving power, R > 2500

DHAS ‘cube-build’ reconstructed image of Channel 2C continuum source.

(Rafael Martinez)

Channel 2B spectral image. (Etalon_1A - continuum source).

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First Coronagraph Test Results

● Results of the first end-end tests at 10.65m of the Four Quadrant Phase mask coronagraph taken by CEA and LESIA last week as part of their MIRIM ETU cryo-test campaign.

● Images show the point source without and with the coronagraph, and a profile comparison.

●The rejection at the peak is about 250, and agrees with the predictions.

● Although the results are preliminary and limited by noise they are already a good indication that the MIRI coronagraphs will work as expected.

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Issues Arising from VM Tests - Status

• FPE– Shifted columns in fastmode – resolved– EM telemetry dropouts – resolved– Excess power dissipation with subarrays – unknown cause in EM, not seen

with FM-class detectors and electronics – investigation on-going

• VM/MTS Focus Issue – Current indications are that the focus error is related to the previous known

issues, particularly in the MOS, and there is now evidence that a range of travel was exceeded causing some disturbances.

– The next significant step is to inspect the hardware after removal from the test chamber which will not be until end of October and several days of diagnostic tests but this may be modified depending on the results of the detailed inspection - investigation on-going

• ICE– VM1 testing raised some NCRs that affected FM design in respect of

temperature sensors monitoring and wheel mechanism drive currents– Modifications to the design incorporated and full release of FM build has

been authorised – resolved

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VM Test Conclusions

• Taken together the two VM test campaigns show that we do basically have a working instrument and test facility

• End-end functioning • Blanket performance • A point source looks like a point source • The cal source illuminates the spectrometer detectors • Imager and spectrometer are both in focus (or not) • The wheels go round, the CCC moves, the sensors can be read out • Throughput is what we expected to see. • We can get dark • Checkout data chain • Annelaing of detectors, detector modes, pom heater works • Enable on-going rationalisation and refinement of test plans • DHAS used to reduce & analyse data, incl. cubes

• There is a lot of test data still to reduce and analyse • There are 9 months in which to correct the MTS• A TIM has been organised to share results with ISIM in more depth.

Recent FM FPM Accomplishments at JPL

• Full qualification program on FPM S/N 101 is complete (and successful)

• Assembly of all three flight FPMs is complete

• FPM S/N 104 (LW Spec) is ready for delivery to FPS– It has passed all acceptance tests

• FPM S/N 105 (SW Spec) and S/N 106 (IC) have completed pre-vibe performance tests and the flight acceptance vibration tests

– Post-vibe performance and alignment tests are in progress

• Spares (2) are on hold until several issues are resolved

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Focal Plane Modules

Pathfinder/Qualification Unit

Front Side

Back Side

FPE Board Status

• The two Power Distribution Units have been checked out and are integrated into the flight chassis.

• Checkout of both SpaceWire boards is complete and they have been integrated into the chassis.

• Three analog signal-chain-electronics boards checked out. Modifications are being installed on all three digital boards.

• The three thermal control boards have been checked out and are ready for integration into the chassis.

FM SCE Analog Board

FM Thermal Control Board

FM SPW Board

FM PDU Board

Focal Plane Electronics Status

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Recent FM Accomplishments in the EC

• FM Wheel Mechanism Assemblies are in various stages of assembly at Zeiss

• FM Spectrometer Main Optics completed acceptance testing at Astron and have been shipped to RAL

• Spectrometer PreOptics assembly is well underway at UK-ATC• ICE production underway at industrial contractor• Flight Deck completed at Leicester and Primary Structure essentially

ready for start of FM Instrument assembly• Double Prism assembly delivered to CEA• Goddard have delivered the Pupil Alignment Reference to CEA• All other MIRIM components manufactured and assembly start is this

week• All IOC components manufactured except POM where rework is needed

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Flight Model Hardware – Primary Structure

Primary Structure Deck Complete, University of Leicester

Primary Structure Struts,Denmark & University of Leicester

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Flight Model Hardware – Spectrometer

SPO – UK Astronomy Technology Centre

Spectrometer Main Optics – Astron

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FM Hardware – Wheel Mechanism Assemblies

Mechanisms – MPIA & Zeiss

Dichroic Wheel UKATCFilter Wheel Disk - CEA

Grating Wheel - Astron

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Recent FM Issues

• Detector Assemblies

– Mother board edge metal – resolved

– Cracking capacitors – resolved

– Loss of pixels during DA build – root cause found, modifying process for future builds

– Heater shorting to detector substrate – under investigation

• Wheel mechanism Assemblies component part issues – Resulted in delays early in new year - revised approach is to move

the assembly and integration of the 3x FM wheel mechanism assemblies ahead of the 2x QMs in order to expedite the FM Instrument schedule - resolved

• Pick-Off Mirror rejected due to unacceptable WFE

– Root cause: very tight geometry constraints and coating that was not present on VM, modified process implemented.

– Currently 2 new mirrors are in production - resolved

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07

8311, 69, 89

03

1

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L

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CONSEQUENCES

54321

New since last JWST PW

Unchanged

Increasing (Worsening)

M - Mitigate

W - Watch

A - Accept

R -Research

Decreasing (Improving)

ApproachLxC Trend**Criticality

High

Med

Low

MIRI Top Risk List & Risk Matrix

* Formerly titled “In-flight External Contamination of Cooler Refrigerant Line”** Topic will be discussed in Cooler presentation

Rank &Trend

RiskID

L C Appr-oach Risk Title

1 83 3 4 RInsufficient Cooler Heat Lift and Margin*

2 89 3 3 RIce Contamination of Detectors Due to Lack of IRSU Support**

3 69 3 3 WTest Dewar Fails Before FPM Test Completion

4 11 3 3 WLate delivery of Wheel Mechanism components delays FM imager and SPO

5 07 2 4 WWheel mechanism qualification program completed after FM OM integration

6 03 2 3 WLate design changes arising from QM & VM

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Conclusions

• Its been a year of hard work for all the team

• The great progress and successes are based on the positive team-work that is the basis of the MIRI partnership

• Next Steps

– Complete VM Test Campaign– assessment of VM results– FPS System tests at JPL– Complete assembly of FPS, IOC, MIRIM and SPO – ISIM and Mission CDRs– Start FM Instrument Assembly early next year

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Back-up Slides

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FM Schedule Status Summary

There is 1 week of schedule margin on the FM delivery date

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MIRI Top Risks- Lowered Rating / Retired

RiskID

Risk Title

Status

JustificationFormer Currrent

84 Parallel Qualification Testing of FM FPM Pathfinder

L=2;C=5 RETIRED Successfully completed flight FPM qualification

80 Insufficient JPL FSW support for OBA after FM FPS delivery

L=3; C=3 L=2; C=3 Funding issues are being worked with GSFC

35 Cooler Heat Dissipation by S/C Inadequate

L=3; C=3 L=2; C=3 S/C design changes from trade study and cooler centerplate design changes maximize heat rejection. Folded into Risk 83.

78 FPE Observation Power Above Allocation

L=3; C=3 L=2; C=3 Early power measurements of SCE analog PWA show expected reduction in power consuption due to use of ±7V power and use of FPGA nap mode. Preliminary FPE Testbed measurements show power reduction from 36W to 27W, not accounting for better converter efficiency at higher loads.

86 Late integration of Cooler Components New

L=2; C=3

Cooler performance problems with the MIRI Optical System due to the late integration of all Cooler components will cause significant schedule delays. Considered to be a low risk at this time.

76 Late FPE parts analysis and Reliability open items

L=3; C=3 RETIRED All analyses are complete.

46 Focal Plane Misalignment at OM Interface

L=2; C=4 L=1; C=3 Successful EM integration shows ICD and process works

58 JPL Test Facilities Booked By Other Projects

L=2; C=4 L=4; C=1 Alternate facilities identified and can be booked without significant delays

45 Detector Assembly (DA) fabrication issues at RVS

L=2; C=3 (L=3;C=4) Process failures in the flight detector development may cause rework risks to DA and delivery delays. Lost a flight DA in this process. New issues are being addressed.

81 Lack of ICE Fault Management details L=2;C=3 L=2; C=2 Information has been received from EC. Work is in process to completely close out this issue.

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421 µW 426 µW 428 µW 435 µW

428 µW

429 µW

425 µW

Subarray Power Dissipation vs LocationFull Frame Power Dissipation

Fast Mode 429 µW

Slow Mode 362 µW

0,0

FPE Testbed Power Dissipation

Power dissipation of EM detec- tors increased by > factor of 3 when moving from right to left. No increase seen with FM testbed (right).

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MIRI Optical Configuration

MIRI Imager(incl.

Coronagraph & LRS)

Spectrometer Pre Optics

(SPO)

Focal Plane Modules (FPM

Primary Structure Deck

Input Optics & Calibration

(IOC)

CFRP Hexapod

Spectrometer Main Optics

(SMO)

Focal Plane Modules (FPMFocal Plane

Modules (FPM)

Interface Connector

Panels (ICP x 3)

Sub-assemblies are tested as units prior to integration:SPO, SMO, Deck, Hexapod, IOC, MIRIM, harness, FPM/FPE

Spectrometer Main Optics

(SMO)

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VM Cryo-Test Campaign – aims

• VM 1 cryotest – We do (or do not) basically have a working instrument and if not we have a good

idea as to why not and how to fix the FM• End-end functioning• Blanket performance• A point source looks like a point source • The cal source illuminates the spectrometer detectors• Imager and spectrometer are both in focus (or not)• The wheels go round, the CCC moves, the sensors can be read out• Throughput is what we expected to see.• We can get dark• Checkout data chain• Annelaing of detectors, detector modes, pom heater works

• VM 2 cryotest– The MTS is basically working (or not) and if not we know what to fix for FM

• e,g. On/off/movement of source/brightness of source is OK or not

– There is no unexpected straylight in either imager or spectrometer– “Dry run” team organisation, scripts etc

• Any other performance tests of the VM are a bonus