SPACETELESCOPESCIENCEINSTITUTE

Operated for NASA by AURA

COS Science Calibration & Instrument Status

TIPS20 Nov 2003

Last COS TIPS Aug 2003

Friedman 2 of 25TIPS - 20 November 2003

COS Instrument Status

• Thermal vacuum & science calibration testing complete– Tests of mechanism stability continuing

• All important performance requirements have been met– Spectral resolution– Sensitivity– Flatfield quality– Scattered light– Wavelength coverage

• COS to be moved to GSFC for storage until launch preparation– Periodic functional and throughput tests to verify instrument

health

Friedman 3 of 25TIPS - 20 November 2003

Thermal Vac & Science Calibration

• All testing completed at Ball Aerospace, Boulder• Initial thermal balance tests and preliminary SI verification

(“Appendix A”) July 2-7.– 21 tests. ~500 data files.– Testing terminated to fix power converters and several other small

items.

• Detailed science calibration (“Appendix B”) Sept 20 – Oct 22.– 109 tests. ~2200 data files.– NUV first, FUV later, to allow pressure to drop to acceptable levels.

• OPUS and CALCOS processed data available with StarView.• STScI support at Ball

– Keyes, Hartig, Sembach, Leitherer, Bohlin, Wheeler, D. Stys, Friedman.

Friedman 4 of 25TIPS - 20 November 2003

COS Detectors

FUV XDL detector NUV MAMA detector

Friedman 5 of 25TIPS - 20 November 2003

Vacuum Chamber Arrangement

Calibration Delivery System external platform provided ultraviolet light sources.

RAS/Cal COS

Cal Delivery System

COS operations

Vacuum pump

RASCAL controlelectronics & computer

Vac chamber operations

pum

ps

Vacuum chamber

Green Room contained operations and data analysis facility

Friedman 6 of 25TIPS - 20 November 2003

Friedman 7 of 25TIPS - 20 November 2003

Science Calibration Test Categories

• Alignment, focus, image quality, resolution• Sensitivity• Wavelength scales• Stray & scattered light• Flat field and S/N• Detector functions• Optical stability & repeatability• Target acquisition algorithms

Friedman 8 of 25TIPS - 20 November 2003

Optical Layout

Friedman 9 of 25TIPS - 20 November 2003

Appendix B FUV Teststest test day date

number name completed

70 FUV focus sweeps2700 FUV HV variability Thur 10/09/032705 FUV HV variability Thur 10/09/032706 FUV HV variability Thur 10/09/032740 FUV dark count rate #1 Thur 10/09/03850 Repeatability monitor #1 Thur 10/09/03

2715 FUV timing threshold settings Fri 10/10/032725 FUV walk settings Fri 10/10/032710 FUV timing threshold settings Fri 10/10/032726 FUV walk settings Fri 10/10/032740 FUV dark count rate #2 Fri 10/10/033600 FUV Accum Check Fri 10/10/031700 FUV cal ss flats S/N=30 Sat 10/11/031210 FUV G130M sensitivity Sat 10/11/031220 FUV G160M sensitivity Sat 10/11/031230 FUV G140L sensitivity Sat 10/11/031240 FUV sensitivity with QE grid off Sat 10/11/033500 FUV OSM1 position checks Sat 10/11/032740 FUV dark count rate #3 Sat 10/11/032300 FUV grating stability Sun 10/12/032305 FUV grating stability Sun 10/12/032355 NUV grating stability Sun 10/12/032355 NUV grating stability Sun 10/12/031265 G225M 2nd order sensitivity Sun 10/12/032800 FUV high local count rate Sun 10/12/033300 FUV BOA throughput & resloution Sun 10/12/032735 Geometrical Correction WCA part Sun 10/12/03

1110 FUV CDS Pt-Ne Group 1 Mon 10/13/032750 FUV resolution, QE grid off Mon 10/13/031120 FUV CDS Pt-Ne Group 2 Mon 10/13/032741 FUV dark count rate, QE grid off Mon 10/13/03850 Repeatability Monitor #2 Mon 10/13/03

3000 FUV Cal SS flats, S/N = 100 Mon 10/13/032306 G130M Grating Stability #1 Mon 10/13/032805 FUV high local count rates G160M Mon 10/13/032735 Geom Corrections WCA Tues 10/14/031450 TA dispersed mode centroids Tues 10/14/031460 TA dispersed light phase 4 Tues 10/14/031470 TA dispersed light phase 5 Tues 10/14/032730 FUV geometric corrections PSA Wed 10/15/032731 Geom Corrections PSA 7x7 pinhole Wed 10/15/032306 G130M Grating Stability #2 Wed 10/15/03850 Repeatability monitor #3 Wed 10/15/03

1720 FUV flats aperture offset 2 Wed 10/15/032100 FUV CO initial spectra Wed 10/15/032110 FUV scattered light Thur 10/16/032120 FUV high quality spectra Thur 10/16/03850 Repeatability monitor 4 Thur 10/16/03

1437 NUV TA flooded aperture with Kr Thur 10/16/032740 FUV dark count rate 3 Thur 10/16/032506 NUV flats with CDS D2 lamp Thur 10/16/031730 FUV flats aperture offset 3 Fri 10/17/032307 FUV stability Fri 10/17/033700 NUV Efficiency Suplement Sat 10/18/033400 Side 2 Mechanism Verification Sat 10/18/03

50 TA1 Focus Sweeps Mon 10/20/032307 NUV stability Mon 10/20/03

50 TA1 Focus Sweeps Tues 10/21/031155 NUV G185M CDS Pt-Ne Spectra in N2 Tues 10/21/031156 NUV G225M CDS Pt-Ne Spectra in N2 Wed 10/22/03

Test Program by D. Ebbets (Ball), E. Wilkinson (CU), and IDT.

Friedman 10 of 25TIPS - 20 November 2003

FUV G130M Spectral Resolution

Segment BSegment A

Friedman 11 of 25TIPS - 20 November 2003

FUV G130M Spectral Resolution

Friedman 12 of 25TIPS - 20 November 2003

NUV G225M Spectral Resolution

17000

18000

19000

20000

21000

22000

23000

24000

25000

26000

27000

28000

29000

30000

2070 2170 2270 2370 2470 2570

lam2186lam2217lam2233lam2250lam2268lam2283lam2306lam2325lam2339lam2357lam2373lam2390lam2410

Requirement

Friedman 13 of 25TIPS - 20 November 2003

Spectral Resolution Summary

• FUV channel– G130M & G160M R > 20,000– G140L R > 2,000

• NUV channel– G185M R > 16,000– G225M & G285M R > 20,000– G230L R > 1,700 (over most of bandpass)

• Bright Object Aperture (BOA) resolution degraded– Wedge in ND filter degrades resolution by factor of ~2.5 for FUV

modes and ~4 for NUV modes.

Friedman 14 of 25TIPS - 20 November 2003

FUV Sensitivity

This point falls outside the specified wavelength range and thus does not violate requirements.

Detector QESegment A

Detector QESegment B

Friedman 15 of 25TIPS - 20 November 2003

NUV Flat Structure

500 1000

500

1000

0

COS G185M NUV P-flat1.36% Poisson rms

Pixel (cross-dispersion)

Pix

el (

disp

ersi

on)

Intrinsic detector scatter (1=3.25%) within the 100x100 pixel box shown in dashed lines

20,000 - 40,000 counts per pixel in each stripe

C B A

Pix

el (

disp

ersi

on)

Friedman 16 of 25TIPS - 20 November 2003

NUV Flatfield S/N

Normalized ratio of first half of exposure to second half

Friedman 17 of 25TIPS - 20 November 2003

FUV & NUV Flat Fields

Friedman 18 of 25TIPS - 20 November 2003

NUV Spatial Resolution

Friedman 19 of 25TIPS - 20 November 2003

Optics Select Mechanism (OSM)

Optics Select Mechanism Two

• Full 360 Degree Rotation

• 101 arcsecond step size, with selectable step rate (78 steps/sec baselined)

• Coarse and fine resolvers provide position feedback

Ferris wheel mode

Friedman 20 of 25TIPS - 20 November 2003

OSM Stability with Time(typical component test results)

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Time

G160MG130M

NCM-1

G140L

~ 4 minutes

1 resel

Helicopter mode

Friedman 21 of 25TIPS - 20 November 2003

G130M Segment A – Helicopter Orientation

-0.906 Arcseconds of Drift

Friedman 22 of 25TIPS - 20 November 2003

G160M Segment A – Helicopter OrientationG160M Seg A Image Motion in Helicopter Orientation

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Time (sec)

Motion (pixels)

X-drift 1

X-drift 2

X-drift 3

X-drift 4

X-drift 5

X-drift 6

X-drift 7

X-drift 8

X-drift 9

X-drift 10

X-drift 11

X-drift 12

X-drift 13

Average

-01.069 Arcseconds of Drift

Friedman 23 of 25TIPS - 20 November 2003

G185M – Helicopter OrientationG185M Image Motion in Helicopter Orientation

-6

-5

-4

-3

-2

-1

0

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Time (secs)

Motion (pixels)

YC1

YC2

YC3

YC4

YC5

YC6

YC7

Average

-9.39 Arcseconds of Drift

Friedman 24 of 25TIPS - 20 November 2003

OSM Stability Summary

• The OSM met stability requirements in component level testing (helicopter mode).

• Science calibration (Ferris wheel mode): OSM1 & OSM2 did not meet requirements in some cases.

• Post science cal GN2 testing (helicopter mode) has shown excessive drift in some test cases.– OSM relaxation may be due to thermal effects. Bench is not thermally

controlled in helicopter mode.

• Ball conducting additional test to further characterize problem.• COWG and COS FIG groups will consider operational

changes to mitigate the problem. COS IS evaluating science impacts.

Friedman 25 of 25TIPS - 20 November 2003

COS Science Calibration Summary and Status• Science calibration complete

– All instrument modes exercised.– Instrument stimulated by continuum, emission line, and absorption line

(O2 and CO) sources.

• Performance is excellent– Resolution, sensitivity, alignment, image quality, focus.

• Flight software performed as expected• OSM stability under investigation• Expect shipment to GSFC shortly• Functional tests every 3 months; NUV throughput tests every

6 months• OPUS and CALCOS processed thermal vacuum test data in

MAST.