1 / 20

SPACE TELESCOPE SCIENCE INSTITUTE

SPACE TELESCOPE SCIENCE INSTITUTE. Operated for NASA by AURA. TIPS / COS TV Update 21 December 2006. Agenda Testing Setup and Status TV Testing Plans Summary NUV Sensitivity Last TIPS presentation: 15 June 2006. Summary of Test Program to Date.

kennan
Download Presentation

SPACE TELESCOPE SCIENCE INSTITUTE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA TIPS / COS TV Update21 December 2006 • Agenda • Testing Setup and Status • TV Testing Plans • Summary • NUV Sensitivity • Last TIPS presentation: 15 June 2006

  2. Summary of Test Program to Date • Completed Environmental Test (TV I) in 2003 • Delivered COS to GSFC in April 2004 • Semi-annual Functional Testing (2004-summer 2006) • Removed, Inspected, Reworked, & Tested MEB boards from August-September 2006 – including replacing all LVPS • Integrated all boards back in the MEBs in September 2006. • COS sucessfully completed Thermal-Vacuum Testing (TV II) in November/December 2006 Keyes (TIPS) - 21 December 2006 Slide 2 of 14

  3. Previous Ground Testing Status Summary • All major performance requirements met in TV I in 2003 • Spectral resolution • Sensitivity • Flatfield quality • Scattered light • Wavelength coverage OSM 1 • TV I testing revealed spectrum drift caused by OSM motions • TAGFLASH Mode (OSM-drift operational correction) • Test at Thermal-Vac II • Lamp Lifetime Tests ongoing at NIST and CU Keyes (TIPS) - 21 December 2006 Slide 3 of 14

  4. COS TV Pics Keyes (TIPS) - 21 December 2006 Slide 4 of 14

  5. 2006 COS Vacuum Test Configuration Original Relay Optics, RAS/Cal, TBF and COS installed in SES New vacuum CDS installed in SES with RAS/Cal, COS Keyes (TIPS) - 21 December 2006 Slide 5 of 14

  6. COS TV Pics -- courtesy of Dave Soderblom Keyes (TIPS) - 21 December 2006 Slide 6 of 14

  7. Ground Science Calibration 2006 • Science calibration tests in Nov/Dec 2006 TV II test at GSFC • Goals of 2006 test plan (“Appendix C”): • Demonstrate continued nominal performance of COS • Exercise new modes and capabilities: e.g., “TAGFLASH” observing mode • Obtain additional information needed to reduce and interpret science data: external FUV flat-field observations • Did not repeat all tests from 2003; only those required to meet above goals • Two-tiered test plan: required tests and optional tests to be executed only if questions arise about the current performance of COS • Close STScI Thermal-Vac Coordination with IDT • Coordinating Thermal-Vac staffing resources and schedules • FUV and NUV Thermal-Vac data processed by OPUS and ingested in MAST • Initial reference file delivery from IDT prior to SMGT in March 2007 Keyes (TIPS) - 21 December 2006 Slide 7 of 14

  8. Science Calibration Test Categories • Alignment, focus, image quality, resolution • Sensitivity • Wavelength scales • Flat field and S/N • Detector functions • Optical stability & repeatability • Target acquisition algorithms • TAGFLASH Keyes (TIPS) - 21 December 2006 Slide 8 of 14

  9. TV II Science Cal Tests Required Tests Contingency Tests • 29 test sequences; items in red are new tests for 2006. • Total run time is approximately 11 days for required tests and 21 days for required+contingency. Keyes (TIPS) - 21 December 2006 Slide 9 of 14

  10. Thermal Vac & Science Calibration • Initial thermal vacuum and thermal balance testing in November • STScI support at GSFC • Hartig, Wheeler, Soderblom, Keyes, Hartig, Friedman. • Detailed science calibration (“Appendix C”) 28 Nov – 8 Dec. • ~25 tests; 1233 data files; ~10 Gbytes raw data. • Included STScI-generated SMS for thorough TAGFLASH testing • First execution of an STScI SMS on SI. • All testing completed at GSFC • Science calibration complete • All primary instrument modes exercised. • Preliminary onsite assessment indicates performance remains nominal • Continuing assessment of resolution, sensitivity, alignment, image quality, focus. • Apparent decline in NUV sensitivity between 2200 and 2900 Å with ONLY the two bare aluminum-coated spectral elements (G225M and G285M) • Flight software and TAGFLASH performed as expected • Continued storage at GSFC; SMGT upcoming (30 March 2007) • Functional tests every 3 months; NUV throughput tests every 6 months • OPUS-processed data will be available with StarView. Keyes (TIPS) - 21 December 2006 Slide 10 of 14

  11. % change: 2006 Sensitivity compared with 2003 Sensitivity • 2003 and 2006 test setup may have systematic differences • Different PMT calibrations • Red-leak in 2003 PMT measurements • No common optic or detector between NUV TA1, G230L and FUV G140L, G160M yet show same ~10% decline decline in common wavelength region; implies external systematic offset Keyes (TIPS) - 21 December 2006 Slide 11 of 14

  12. NUV STIS sensitivities assume zero slit losses; typical loss is ≥20%. Keyes (TIPS) - 21 December 2006 Slide 12 of 14

  13. COS offset by apparent 20% NUV decline Keyes (TIPS) - 21 December 2006 Slide 13 of 14

  14. Sensitivity • Analysis of FUV and NUV sensitivity is very preliminary at this point • Statistically significant sensitivity degradation between 2003 and 2006 for only G225M and G285M spectral elements • These are the only gratings with bare aluminum coatings • Degradation is not uniform with wavelength • No degradation since 2003 at 2100 Å where degradation may have stabilized • Even with measured degradation, COS retains significantly higher throughput than STIS E230M and the COS MAMA is predicted to have a factor of 4 lower background • Spare NUV gratings and witness samples will be evaluated • Possible amelioration? • very difficult to access OSM2 mechanism and NUV gratings Keyes (TIPS) - 21 December 2006 Slide 14 of 14

  15. Background information Keyes (TIPS) - 21 December 2006 Slide 15 of 14

  16. FUV Sensitivity Keyes (TIPS) - 21 December 2006 Slide 16 of 14

  17. COS Optical Layout Keyes (TIPS) - 21 December 2006 Slide 17 of 14

  18. 170 mm COS Detectors – FUV XDL Top View Keyes (TIPS) - 21 December 2006 Slide 18 of 14

  19. COS Detectors – NUV MAMA in the enclosure Keyes (TIPS) - 21 December 2006 Slide 19 of 14

  20. FUV MCP (1 of 2 segments) NUV MAMA PtNe Wavecal External Science Internal PtNe Wavecal C B A C B A External Science COS Spectral Layout for Simultaneous Internal Wavecals and Science Spectra • Obtain (continuous or flashed) internal PtNe spectra at same time as science exposure • Track internal PtNe lines and apply shifts to science spectrum (all events time-tagged) in COS data pipeline Keyes (TIPS) - 21 December 2006 Slide 20 of 14

More Related