SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA COS Science Calibration & Instrument Status TIPS 20 Nov 2003 Last COS TIPS Aug 2003

Friedman 2 of 25 TIPS - 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 25 TIPS - 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 25 TIPS - 20 November 2003 COS Detectors FUV XDL detectorNUV MAMA detector

Friedman 5 of 25 TIPS - 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 control electronics & computer Vac chamber operations pumps Vacuum chamber Green Room contained operations and data analysis facility

Friedman 6 of 25 TIPS - 20 November 2003

Friedman 7 of 25 TIPS - 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 25 TIPS - 20 November 2003 Optical Layout

Friedman 9 of 25 TIPS - 20 November 2003 Appendix B FUV Tests Test Program by D. Ebbets (Ball), E. Wilkinson (CU), and IDT.

Friedman 10 of 25 TIPS - 20 November 2003 FUV G130M Spectral Resolution Segment B Segment A

Friedman 11 of 25 TIPS - 20 November 2003 FUV G130M Spectral Resolution

Friedman 12 of 25 TIPS - 20 November 2003 NUV G225M Spectral Resolution Requirement

Friedman 13 of 25 TIPS - 20 November 2003 Spectral Resolution Summary FUV channel –G130M & G160MR > 20,000 –G140LR > 2,000 NUV channel –G185MR > 16,000 –G225M & G285MR > 20,000 –G230LR > 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 25 TIPS - 20 November 2003 FUV Sensitivity This point falls outside the specified wavelength range and thus does not violate requirements. Detector QE Segment A Detector QE Segment B

Friedman 15 of 25 TIPS - 20 November 2003 NUV Flat Structure COS G185M NUV P-flat 1.36% Poisson rms Pixel (cross-dispersion) Pixel (dispersion) Intrinsic detector scatter (1  =3.25%) within the 100x100 pixel box shown in dashed lines 20, ,000 counts per pixel in each stripe C B A Pixel (dispersion)

Friedman 16 of 25 TIPS - 20 November 2003 NUV Flatfield S/N Normalized ratio of first half of exposure to second half

Friedman 17 of 25 TIPS - 20 November 2003 FUV & NUV Flat Fields

Friedman 18 of 25 TIPS - 20 November 2003 NUV Spatial Resolution

Friedman 19 of 25 TIPS - 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 25 TIPS - 20 November 2003 OSM Stability with Time (typical component test results) G160M G130M NCM-1 G140L ~ 4 minutes 1 resel Helicopter mode

Friedman 21 of 25 TIPS - 20 November 2003 G130M Segment A – Helicopter Orientation Arcseconds of Drift

Friedman 22 of 25 TIPS - 20 November 2003 G160M Segment A – Helicopter Orientation Arcseconds of Drift

Friedman 23 of 25 TIPS - 20 November 2003 G185M – Helicopter Orientation Arcseconds of Drift

Friedman 24 of 25 TIPS - 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 GN 2 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 25 TIPS - 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 (O 2 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.