2011 March 17 1

JWST FGS & TFI CVAC Risk Mitigation Tests

Pierre Chayer, André Martel, Alex Fullerton, Ed Nelan, Kevin Volk, Anand

Sivaramakrishnan, Sherie Holfeltz, Comdev Canada, CSA, UdeM, HIA

2011 March 17 2

Fine Guidance Sensor (FGS) Optical Layout

2 m

100 mm

Pick-Off Mirror

TMA Mirrors

Focus Mirror

Detectors

Role of FGS: Provides centroids to the Attitude Control System.

2011 March 17 3

FGS Optical Assembly

2011 March 17 4

Tunable Filter Instrument (TFI) Optical Layout

Narrow Band Imager

2011 March 17 5

TFI Optical Assembly

Dual Wheel

CollimatorTMA

Camera TMA

Etalon

DetectorAssembly

KinematicMounts

2011 March 17 6

FGS & TFI Test Setup

2011 March 17 7

Chamber Darkness

2011 March 17 8

CVAC Risk Mitigation Test Objectives

• Verify modifications made to FSW for control of FGS.• Verify modifications made to FSW for image processing.• Continue with Risk Mitigation Activities for CVAC

Performance Test.– Collect data that can be used to mitigate risk for the CVAC

Performance Test in June.– Performance test for TFI without the Etalon.

• Complete Science Team Characterization activities

2011 March 17 9

CVAC Risk Mitigation Test

• 24 Day Test from January 10th to February 3rd.

• Test Started – January 10th 2011• Cool-down Started – January 10th 2011• Stable at 37 K – January 16th 2011• FGS Powered Down – January 22nd 2011• FGS Powered Up – January 25th 2011• Completion of Test Plateau – January 26th 2011• Warm-up Complete – January 29th 2011• Test Completed – February 3rd 2011

2011 March 17 10

G1 Best Focus

2011 March 17 11

FGS Cal Lamp

2011 March 17 12

G2 & G1 images with Cal Lamp

2011 March 17 13

Feature Observed in G1 Cal Images

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FGSCVACG1PFMIFFF_6_497_SE_2011-01-22T04h23m11 CnS60

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- Perhaps light exits the instrument, hits a reflective surface such as OGSE rack (only for G1) and re-enters to image the Cal source…? output?

Suggestion that the shape is reminisicent of the Cal source output? But how would that be imaged? Why only G1?

2011 March 17 14

Feature Observed in G1 Cal Images

It is theorized that light from the cal source may exit the instrument, reflect from an external surface (OGSE?) and re-enter, reflect from the cal source output, and be imaged on the detector.

Looking at the cal source testing, one can see a “jet” at the edge where the hemispheres join.

Is there an optical path for the “lines” to also show up in the image?

“Jet”

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FGSCVACG1PFMIFFF_6_497_SE_2011-01-22T04h23m11 CnS60

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2011 March 17 15

TFI Calibration Lamps

2011 March 17 16

TFI Cal Line

2011 March 17 17

Summary

• All objectives were completed with varying degrees of success.

• The team feels more confident to carry out the Proto-Flight CVAC Performance Test in June.

• The STScI team is looking forward to supporting the next round of tests.