SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by

SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA TIPS 21 August 2003 (Last COS TIPS: Dec 2002) An Update on the COS Development Status COS Integrated SI (Aft End) 1

COS Timeline Summary • Instrument integration activities (Jan-Mar 2003) – Calibration platform installed, electronics, enclosure, etc – FUV 02 (flight spare) detector qualifications completed • FUV detector swap and alignment (March-April 2003) – FUV 02 performance better at longer ; “flatter” throughput – Alignment checked under N 2 purge with CAOS/HOMS • Environmental tests of integrated instrument (April 2003) – GSFC: EMI/EMC, acoustics, vibration, metrology • Initial thermal balance, alignment, and testing in vacuum completed in July 2003 – To confirm focus/spectral resolution/throughput/operations 2

COS Timeline Summary (con’t) • Instrument currently out of vacuum chamber at Ball – Working issues discovered during initial testing • • • T-Vac activities to begin September 11 Science calibration to occur September 18 - October 12 Delivery to GSFC expected in late October 2003 Integrated pipeline testing in May 2004 SMGT planned for late July 2004 Working to launch date of May 2005 3

COS: pre-acoustic test; packing for return to Ball 4

COS Integrated SI and Enclosure 5

COS Issues of Interest • Spectra in Bright Object Aperture (BOA) have coma o – ND 2 filter (2 mm cube) has 0. 25 wedge – Resolution degraded by factor of ~4 in NUV, less in FUV – No serious science impact • Spectral lines sometimes found to be “tilted” under N 2 purge in CAOS/HOMS after FUV 02 detector swap – Time variable, observed for FUV external lamp spectra – Most likely related to failing Pt. Ne calibration lamp – Not seen after new lamp installed or in later vacuum tests 6

Removal of COS from Vacuum Chamber • Internal ion pressure gauge not functioning – Problem traced to incorrect signals fed to electronics box; fixed • RASCAL chief ray not aligned as it was prior to pump down – Chief ray remeasured; tip/tilt mirrors corrected • Interpoint converter found to be faulty after check of calibration lamp voltage and current telemetry – LVPS board removed, x-rayed at GSFC – – Solder leads lift from solder joints under vacuum Other converters (5) x-rayed to ensure sufficient strain relief Spares also being checked Stiffener plates (Kovar) being bonded to tops to prevent stress 7

STSc. I Thermal Vacuum Activities • Instrument scientists supported initial science verification activities in late June - early July in Boulder, CO – Hartig, Leitherer, Sembach participated on-site – Friedman analyzed spectral repeatability data – Approx. 500 datasets produced in two week period • Science calibration data archived in MAST – – All data run through OPUS and initial CALCOS processing T-Vac retrieval screen available Automated data transfer algorithms developed and implemented Data also stored locally on COS machines for rapid analysis • Keyword consistency checking – Fidelity of FITS keywords being checked with help from Rose/Hodge 8

COS Initial Testing Summary • Instrument is performing as expected optically – – – Spectral resolution ~ 20, 000 in medium resolution modes Throughput meets/exceeds CEI specifications Geometric distortion can be corrected accurately Grating motion repeatability is as good as expected Spatial resolution ~ 1 arc sec • Final calibration activity plan being finalized by CU/Ball – Close cooperation with STSc. I • Testing to resume in mid-September 9

Sample COS FUV Spectrum External Pt. Ne calibration lamp (no distortion correction) 10

Sample COS NUV Spectrum External Pt. Ne calibration lamp 11

Initial FUV Spectral Resolution Results - G 130 M External Pt. Ne calibration lamp R = / 12

Initial FUV Spectral Resolution Results - G 160 M External Pt. Ne calibration lamp R = / 13

G 185 M Initial NUV Spectral Resolution Results External Pt. Ne calibration lamp G 225 M R = / G 285 M 14

Initial COS Efficiency Estimates Grating G 130 M-B G 130 M-A G 160 M-B G 160 M-A G 140 L G 185 M G 225 M G 285 M G 230 L TA 1 -Brt Wavelength (Å) 1248 1327 1430 1621 1327 1846 2487 2695 2262 2487 Efficiency 0. 174± 0. 018 0. 113± 0. 017 0. 120± 0. 011 0. 075± 0. 016 0. 083± 0. 014 0. 0355± 0. 0043 0. 0248± 0. 0023 0. 0189± 0. 0014 0. 0246± 0. 029 0. 0424± 0. 0043 0. 0031± 0. 0003 Requirement >0. 103 >0. 077 >0. 018 >0. 023 >0. 017 >0. 021 No req From Wilkinson et al. (2003, SPIE) 15

Dispersion (pixels) Initial Spatial Resolution Results TA 1 Image (NUV) Double pinhole aperture 1” (~40 pixels) separation 40 30 20 Images are clearly resolved 10 0 10 20 30 40 50 60 Cross Dispersion (pixels) 16

Initial FUV Grating Motion Repeatability Results 17

Initial NUV Grating Motion Repeatability Results 18

STSc. I Ground System Development and COS Pipeline • Bright object screening tool (ROBOT) in progress • Flatfield commanding rework complete • HST data volume study – COS on-orbit and pipeline estimates updated • Bench testing of command certification SMS (T. Wheeler) • Planning of Integrated Pipeline Test started • COS Pipeline (CALCOS) – Most modules are now complete Spectral merging procedures for FP-POS positions in progress – Testing to occur on integrated SI data from T-Vac – 19

SMOV & SMGT • Successful SMOV 4 requirements review 30 July 2003 at GSFC • Special commanding definition required by Oct 2003 – COS Operations Working Group will establish requirements • SMOV activity summaries (Phase 1 proposals) definition Nov-Dec 2003 – Review presently scheduled for late Jan 2004 • SMGT now planned for late July 2004 20

STSc. I User Support § STSc. I Instrument Division COS Staff – IS: Keyes, Sembach, Friedman; DA: Mc. Master – Leitherer transferred from COS to JWST in July 2003 (supporting T-Vac) § COS Handbooks – Mini-handbook for Cycle 13 being revised (August 2003) – Instrument handbook outline exists, work to continue after T-Vac § COS Exposure Time Calculators – Spectroscopic ETC software development in progress – Target acquisition ETC requirements delivered to APT group – Completion of ETCs expected in January 2004 § COS Website http: //www. stsci. edu/instruments/cos 21