SPACETELESCOPESCIENCEINSTITUTE

Operated for NASA by AURA

COS Status

FUV Detector

“1-bounce design”

NUV Detector

HST aberration fully-corrected

Calibration Platform

COS Status

SI stored at GSFC since April 2004; periodic functional testing

Removed, inspected, reworked, & tested MEB boards from August-September 2006 – including replacing all LV power converters

COS successfully completed Thermal-Vacuum Testing (TV II) in November/December 2006

COS Status: SI testing-related

Thermal-Vac testing at GSFC– Demonstrated continued nominal performance of COS– Exercised new modes and capabilities: e.g., “TAGFLASH” observing mode

STScI participated on-site in Thermal-Vac II activities– supported alignment and science calibration activities– Prepared and executed comprehensive test of TAGFLASH mode

All TV data (~10 Gbytes from 1200 exposures) tranferred to STScI– will be processed through OPUS and archived in MAST for retrieval via StarView

Wavelength-dependent NUV sensitivity decline observed– Up to 15% decline only for bare Al-coated gratings and λ > 2100 Ǻ

> may be due to systematic differences in test setup– Witness sample mirrors show no degradation; surrogate spare gratings are

presently being tested at GSFC– All sensitivities measured in 2006 testing are within spec and remain at least 3x

more efficient than equivalent STIS E230M modes Continued storage at GSFCContinued storage at GSFC

– Functional tests every 3 months; NUV throughput tests every 6 monthsFunctional tests every 3 months; NUV throughput tests every 6 months– Test data will be archived in MASTTest data will be archived in MAST

COS Status: STScI

TAGFLASH : – Thorough successful testing by STScI at

Thermal-Vac II– Program prepared entirely with GO tools

(APT); first execution of STScI SMS on SI– Obtains wavelength calibration data by

flashing cal lamp during TIME-TAG exposures rather than as a separate exposure; achieves greater observing efficiency and allows removal of any mechanism motions

FUV MCP (1 of 2 segments)

External Science

Internal PtNe Wavecal

Exposure Time Calculator (ETC)– Spectroscopic ETC: now in testing through April 2007– Target Acquisition and Imaging ETC: summer 2007

Bright Object Protection– User tool in APT: testing now through April 2007; incorporates GALEX

Documentation– Distributed mini-HB version 3 with Cycle 17 CfP– Instrument Handbook being drafted in preparation for release in Cycle 17

COS Status: STScI

STScI preparing SMS for SMGT testingSTScI preparing SMS for SMGT testing– Test will occur in late July 2007Test will occur in late July 2007– SMS will exercise all COS science and calibration-related modes in realistic usage scenariosSMS will exercise all COS science and calibration-related modes in realistic usage scenarios– Resultant data will be processed through pipeline and archivedResultant data will be processed through pipeline and archived

SMOV4 preparationsSMOV4 preparations– STScI, in consultation with COS IDT, prepared updated set of comprehensive requirements; STScI, in consultation with COS IDT, prepared updated set of comprehensive requirements;

formal review mid-March 2007formal review mid-March 2007– Activity summaries (program phase I) to be prepared in summer 2007; review in fall 2007Activity summaries (program phase I) to be prepared in summer 2007; review in fall 2007

Backup Slides

STScI COS Team Activities FY07

Instrument Handbook completion and delivery Thermal-Vac II support; TAGFLASH analysis SMGT program preparation and test support Pipeline testing, special commanding, reference files SMOV4 verification, calibration proposal development Data Handbook preparation Aperture definition and world coordinate system development ETC/BOP completion and delivery Cumulative Image development Associations testing Keyword updates Cycle 17 Call for Proposals GTO Target Review

Ground Science Calibration 2006

Science calibration tests in Nov/Dec 2006 TV II test at GSFCScience calibration tests in Nov/Dec 2006 TV II test at GSFC Goals of 2006 test plan (“Appendix C”):Goals of 2006 test plan (“Appendix C”):

– Demonstrate continued nominal performance of COSDemonstrate continued nominal performance of COS– Exercise new modes and capabilities: e.g., Exercise new modes and capabilities: e.g., “TAGFLASH” observing mode“TAGFLASH” observing mode– Obtain additional information needed to reduce and interpret science data: Obtain additional information needed to reduce and interpret science data:

external FUV flat-fieldexternal FUV flat-field observations observations Did not repeat all tests from 2003; only those required to meet above goalsDid 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 Two-tiered test plan: required tests and optional tests to be executed only if

questions arise about the current performance of COSquestions arise about the current performance of COS Close STScI Thermal-Vac Coordination with IDTClose 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 July 2007

Science Calibration Test Categories

Alignment, focus, image quality, resolutionAlignment, focus, image quality, resolution SensitivitySensitivity Wavelength scalesWavelength scales Flat field and S/NFlat field and S/N Detector functionsDetector functions Optical stability & repeatabilityOptical stability & repeatability Target acquisition algorithmsTarget acquisition algorithms TAGFLASH TAGFLASH

Sensitivity

Statistically significant sensitivity degradation between 2003 and 2006 for Statistically significant sensitivity degradation between 2003 and 2006 for onlyonly G225M and G285M G225M and G285M spectral elements spectral elements

– These are the only gratings with bare aluminum coatingsThese are the only gratings with bare aluminum coatings– Test-related systematics can not be ruled out as source of differences between Test-related systematics can not be ruled out as source of differences between

2003 and 2006 measurements2003 and 2006 measurements– Degradation is not uniform with wavelengthDegradation is not uniform with wavelength

> No degradation since 2003 at 2100 No degradation since 2003 at 2100 Å whereÅ where degradation may have stabilized degradation may have stabilized– Even with measured degradation, COS retains significantly higher throughput 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 than STIS E230M and the COS MAMA is predicted to have a factor of 4 lower backgroundbackground

– Witness samples show NO degradationWitness samples show NO degradation– Spare NUV gratings presently being evaluated at GSFCSpare NUV gratings presently being evaluated at GSFC

Possible amelioration?Possible amelioration?– very difficult to access OSM2 mechanism and NUV gratingsvery difficult to access OSM2 mechanism and NUV gratings