Cycle 21 COS Calibration Plan. Julia Roman-Duval Justin Ely & COS/STIS Team 9/10/2013

Transcription

1 Cycle 21 COS Calibration Plan Julia Roman-Duval Justin Ely & COS/STIS Team 9/10/2013 1

2 Cycle 21 Instrument Usage Statistics Based on Phase II Submissions COS orbits comprise 30% of all prime orbits in Cycle 21 Instruments* Prime Orbits Usage SNAP Orbit Usage ACS 9.17% 37.46% COS 30.12% 4.68% STIS 15.98% 21.45% WFC % 36.41% FGS 0.03% --- 2

3 COS Cycle 21 Usage Statistics Based on Phase II Submissions Total science exposures breakdown by Mode and Grating Configuration Grating Percentage of COS Prime Science Exposures Percentage of COS SNAP Science Exposures COS/FUV G140L 20.9% * 94.7% G130M 41.5% ** --- G160M 26.1% --- COS/NUV G230L 3.5% --- G185M 1.9% --- G225M 2.7% --- G285M 2.7% --- MIRROR A/B 0.7% 5.3% * 56% of total G140L observing time goes to exposures using 1280 (44% -1105) ** 23.5 % of total G130M observing time goes to exposures in the blue Modes : 1222 (76.6%), 1055 (10.63%), 1096 (12.77%) 3

4 COS Cycle 21 Calibration and Monitor Orbits Request Prop. ID Title External Internal Frequency FUV Monitors Cycle 20 Allocation COS FUV Spectroscopic Sensitivity Monitor 23 (10) 9x1 using GD71, 12 using WD COS FUV Detector Dark Monitor x5 (5/wk) 260 COS FUV Internal/External Wavelength Scale Monitor 3 1x3/(M + L) 2 COS PtNe Lamp Cross-calibration 1 0 COS Observations of Geocoronal Ly α Emission 4 4 COS FUV Gain Maps after HV changes COS FUV Detector Recovery After Anomalous Shutdown NUV Monitors 2 + (2/change) (17) (17) COS Target Acquisition Monitor 2+(4) 2x1 NUV Spectroscopic Sensitivity Monitor 6 3x1/(L + M) 6 External parallel orbits allocated with a STIS program. () Contingency orbits not included in Cycle 21 request. Green indicates executing this cycle only NUV Detector Dark Monitor 52 52x1 (2/alt. wk) 52 NUV Internal/External Wavelength Scale Monitor 3 3x1 3 NUV Focus sweep 1 1x1 0 NUV MAMA Fold Distribution 1 * 1x1 1 NUV Detector Recovery After Anomalous Shutdown (4) (4) Cycle 21 Request 38+(10) (21)+(2 /HV change) COS side 2 programs (already approved) are tracked at the end of this presentation 357 4

5 COS Calibration and Monitor Orbits Request by Cycle Programs External Orbits Internal Orbits Parallel Orbits Total Orbits Cycle (21) Cycle (21)+5 Cycle (21)+5 Cycle (21) (21)+4 Cycle (21) (21)+4 External Orbit Requests continue to decrease in an attempt to preserve the lifetime of the COS FUV detectors. Internal Orbit Requests have increased primarily due to an increased cadence for the FUV dark monitor beginning in Cycle 20. The cadence for this program doubled from 5 internal exposures every two weeks to 5 exposures each week (130 to 260) 5

6 COS FUV Spectroscopic Sensitivity Monitor PI: Azalee Bostroem Purpose Description Fraction GO/GTO Programs Supported Observations Monitor the sensitivity of each FUV grating mode to detect any change due to contamination or other causes. The FUV gratings are the most heavily used modes on COS and have also experienced several changes in the time-dependent spectroscopic sensitivity since launch. These trends appear to be grating-, segment-, and wavelength dependent. To track the time dependent sensitivity as a function of wavelength we will obtain exposures in all FUV gratings every month. There will be 2 types of monitoring sequences which will occur on alternating months. The complete monitoring sequence will use 3 orbits in 2 visits (except May July when GD71 is unavailable). The 1 orbit visit will cover the G130M/1096/FUVB, G160M/1577/FUVA, and G160M/ 1623/FUVA modes. The 2 orbit visit will cover G130M/1222, G130M/1291, G130M/1327, G130M/1055/FUVA, G160M/1577/FUVB, G160M/1623/FUVB, G140L/1105, G140L/1230 modes. These comprise the reddest and bluest central wavelengths of each grating with additional coverage of the G130M blue modes. The reduced monitoring sequence in alternating months will use a 1 orbit visit to monitor the complete wavelength range of the standard modes using one central wavelength per grating. The modes covered are G130M/1291, G160M/1623, and G140L/1230. This reduced monitoring scheme, relative to C20, is put in place in C21 given that the slopes of the TDS seen to have stabilized at ~0%. Should any drastic changes occur, the contingency orbits will be activated. 88% of COS exposure time 23 external orbits + (10 contingency external orbits) Analysis 10 FTE weeks Products Time-Dependent Sensitivity Reference File as necessary and a summary in the end of cycle ISR Accuracy Goals Scheduling & Special Requirements SNR of 15 per resel at wavelength of least sensitivity for the standard modes, SNR of 25 per resel at wavelength of most sensitivity for the blue modes. For the blue modes, this will ensure S/N > 15 for λ> 1030 Å for 1096/FUVB, λ>1130 Å for 1055/FUVA and 1222/FUVB Complete monitoring sequence should occur every 2 months starting in December The reduced monitoring sequence should occur every 2 months starting in November GD71 is unschedulable May - July The FUVA turn-off of the GD71 visit should be hidden in the GS-ACQ Changes from Cycle 20 Added G130M/1055/FUVA to monitor behavior of segment A at short wavelengths Reduce complete monitoring to bi-monthly and implement reduced monitoring bi-monthly to reduce lifetime impact 6

7 New in C21: Increased coverage of FUVA TDS is segment and wavelength dependent C20 FUVA wavelength coverage stops at 1223 Å C21 wavelength coverage monitors full FUVA wavelength range (adding 1055/FUVA for no additional orbit request) Added FUVA coverage in Cycle 21 7

8 TDS Trends Trends flat and stable since mid

9 New in C21: reduced monitoring Complete (3 orbit) monitoring bi-monthly o o GD71 (1 orbit): G130M/1096/FUVB, G160M/1577/FUVA, G160M/1623/ FUVA WD0308 (2 orbits): G130M/1055/FUVA, G130M/1222, G130M/1291, G130M/1327, G160M/1577/FUVB, G160M/1623/FUVB, G140L/1105, G140L/1230 Reduced (1 orbit with WD0308) monitoring on alternating months o o o Monthly coverage of ü ü ü G130M/1291 G160M/1623 G140L/1230 combined with the solar cycle data will allow us to detect dramatic changes in trend on comparable time scales to previous cycles Will save 10 orbits compared to C20 ü These 10 orbits are saved as contingency orbits to be triggered in 9 the event that drastic changes in TDS trends are detected

10 COS FUV Detector Dark Monitor P.I. Justin Ely Purpose Description Fraction GO/GTO Programs Supported Observations Perform routine monitoring of FUV XDL detector dark rate. The main purpose is to look for evidence of a change in the dark rate, both to track on-orbit time dependence and to check for a developing detector problem. Monitor the FUV detector dark rate by taking TIME-TAG science exposures with no light on the detector. Five times every week a 22-min exposure is taken with the FUV detector with the shutter closed. The length of the exposures is chosen to make them fit in Earth occultations. All orbits < 1800s. 88% of COS total exposure time 260 internal orbits Analysis Products 4 FTE weeks Provide ETC and IHB dark rate estimates, along with weekly monitoring for changes and a summary in the end of cycle ISR. Update monitor and COS webpages. As allowed by resources and necessitated by data quality: improve dark subtraction method and update bad-pixel tables. Accuracy Goals Obtain enough counts to track changes on timescales of ~1-2 months. Scheduling & Special Requirements 5 times every week during Earth occultations. Changes from Cycle 20 None 10

11 FUV Dark Current Plots In the ETC for C21: 3e-6 cts/pix/s In the ETC for C21: 2e-6 cts/pix/s 11

12 COS FUV Internal to External Wavelength Scale Monitor P.I. Paule Sonnentrucker Purpose Description Fraction GO/GTO Programs Supported Observations This program monitors the offsets between the wavelength scale set by the internal wavecal versus that defined by absorption lines in external targets. This program monitors the offset between the internal and external wavelength scales: this offset is referred to as "DELTA" in the wavelength dispersion reference file and corrects for the shift between the WCA and PSA in TV03 versus the shift between the WCA and PSA in orbit : (WCA-PSA)_TV03 - (WCA - PSA)_orbit. Analysis of TV data indicates that this DELTA (offset) is cenwave and FPPOS independent for a particular grating, but it is grating dependent. To verify and monitor this, this program observes some cenwaves at different FPPOS. All orbits > 1800s. 88% of COS total exposure time. 3 external orbits and all orbits > 1800s. Analysis 4 FTE weeks Products Update of wavelength dispersion reference file if necessary and a summary in the end of cycle ISR. Accuracy Goals Scheduling & Special Requirements G140L 150km/s, pixels G130M 15km/s, pixels G160M 15km/s, pixels ORIENT for some exposures to avoid bright field targets. These observations are taken once a year. Changes from Cycle 20 1 orbit for monitoring of the Blue mode cenwaves at 1096 and 1222 has been added to the program for a total of 3 orbits. 12

13 Justification Blue modes are now significantly used For standard modes, we can interpolate the zero-point offset between extreme cenwaves to obtain offset at intermediate cenwaves o o o o o This is not possible for the blue modes We need a baseline for wavelength monitoring Currently only one data set acquired at LP2 during C20 using a wavelength calibration target Cross-check consistency of wavelength scale: Between 1096/FUVA & 1222/FUVB Between 1222/FUVA & 1291/FUVA Between 1096,1222 and FUSE, STIS E140M data Residual 13 pixel stretch across detector for the 1222 gives further motivation to monitor this mode vs time 13

14 Stellar lines ISM lines ISM lines only STIS E140M COS

15 Instrumental set up In addition to the standard mode monitoring (identical to C20), we will monitor the following modes: o o G130M/1222: ü It is the most used blue mode (8% of COS FUV time) ü Residual 13 pixel stretch needs monitoring G130M/1096: ü Dispersion solution is similar between 1055 and 1096 ü 1096 allows better S/N (higher throughput) One additional external orbit compared to C20, for a total of 3 external orbits S/N = 15/resel on the line required for the cross-correlation: o S/N = 15 on the continuum for the 1096 o S/N = on the continuum for the 1222 (weaker metal lines) 15

16 16

17 COS PtNe Lamp Cross-Calibration P.I. Steve Penton Purpose Description Coeval internal exposures of both COS PtNe lamps are needed to cross-calibrate the COS PtNe lamps in case of a lamp failure to minimize impact on science programs. Deuterium lamps have a more homogenous and can be easily interchanged without affecting the calibration programs for which they are used. For that reason, no mapping of both Deuterium lamps is pursued in C21. FUV and NUV low-resolution spectra are needed to calculate the TAGFLASH times for PtNe #2 in case PtNe #1 fails. NUV imaging exposures are needed to determine TA exposure times of PtNe#1 lamp in case PtNe #2 fails. All spectra will be taken at medium current, all imaging will be taken at the low current level. Fraction GO/GTO Programs Supported 100% (all programs would be affected by a wavecal lamp failure) Observations Analysis Single FUV/G140L/1105 exposures will be obtained with each lamp. Exposures with three CENWAVEs of NUV/G230L will be obtained with each lamp to cover the entire NUV range. NUV WCA images for all combinations of PSA/BOA + MIRRORA/B. Total time is 1 internal orbit. Obtain COS lamp ratio versus wavelength for all FUV gratings and four imaging modes. Calculate PtNe#2 TAGFLASH times for all FP-POSs and PtNe#1 Target Acquisitions times for all imaging modes and FP-POS=3 positions. Products TAGFLASH exposure time tables for PtNe#2. TA exposure times for PtNe#1. Accuracy Goals Need to be able to predict count rates to within 10%. Scheduling & Special Requirements Special commanding will be needed to enable the wavecal lamps in unsupported modes. Changes from Cycle 20 New program 17

18 Motivation Currently, the COS PtNe #2 lamp is only used for short flashes during target acquisition (TA). PtNe #1 is used for all TAGFLASHs/WAVECALs. Every lamp is different, and evolves in its own way: o Due to differences in evolution with age and usage between lamps, we cannot cross-calibrate the two lamps using lamp ratios from ground data. Should we lose either lamp, we should be prepared to adjust the exposure times on the remaining lamp to cover the existing needs. o o Minimal downtime: Tagflash durations need to be calibrated in advance If PtNe #2 fails, the exposure times required for PtNe#1 to take over TA duty involve only the FP=3 CENWAVEs and MIRRORA, B exposures. o o If PtNe #1 fails, we need to know the new TAGFLASH times for ALL FPs. Pending the results of the analysis, we may have to repeat this program every few years (if the lamps ratios have diverged from ground testing) The Deuterium lamps are have a homogenous behavior and are directly interchangeable as they have the same current settings o Only used for special calibration programs 18

19 Ground Lamp Ratio At the same current level, PtNe #1 was almost twice as bright as PtNe #2 < 1600Å. Above 1600Å, PtNe #1 was only about 10% brighter than PtNe #2. The spectrum below 1600Å is dominated by the Pt II lines. G160M G130M MiRRORA (Lo 6/3 ma) MiRRORB (Lo 6/3 ma) Each lamp has 3 current settings, which are different for each PtNe lamp o The Low (Lo) setting is used for imaging TA. At the Low setting, PtNe #1 is 5.5x brighter than PtNe #2. o The PtNe #1 current levels are 6, 10, & 18 ma. o The PtNe #2 current levels are 3, 10, & 14 ma. For a given current, the lamp r a t i o o n l y d e p e n d s o n 19 wavelength (not grating)

20 COS Observations of Geocoronal Lyman-α emission PI: Sean Lockwood Purpose To obtain COS G130M spectra of geocoronal Lyman-α and other airglow emission lines with S/N ratios sufficient to trace the line wings of Lyman-α Description Fraction GO/GTO Programs Supported Observations Analysis Products Obtain parallel airglow spectra with COS/FUV to characterize the profile of airglow lines. Visible in G130M/1327: H I ; O I , , , , ; N I % (G130M observations) 4 external parallel orbits (in parallel with STIS MAMA TDS and focus monitor) ~1.5% of lifetime at brightest Ly-α pixel for each FP-POS (4 FPPOS used) 0.2 FTE day Update of the website listing airglow datasets. Observers must reduce these data themselves. Summary in end of cycle ISR Accuracy Goals SN = 1.5 per pixel at 1213 A Scheduling & Special Requirements Parallel with STIS MAMA TDS monitor. Visits of primary observations need to be approximately equally spaced throughout Cycle 21. Roll angle must be chosen to avoid objects in the COS PSA or BOA apertures. Changes from Cycle 20 Requirements have been achieved (10,000s) for the 1291, so switch to the 1327 (second most used cenwave) 20

21 COS FUV Detector Gain Map after HV Changes PI: David Sahnow Purpose Description Obtain gain maps of the FUV detector before and after any change to the high voltage levels, to check that the expected modal gain is achieved, and to constrain dependency of modal gain on HV Immediately before a change to the high voltage, use the deuterium lamp to illuminate the entire region of the COS FUV detector currently being used to collect spectra. Repeat after the voltage has been changed, and before any other FUV observation is executed. Exposure times need to be adjusted as lamp ages. Fraction GO/GTO Programs Supported 88% Observations Analysis 2 internal orbits for every HV change (2 intermal orbits for C contingency/additional change) Existing CCI / gain map procedures will be used to process these data Products Gain map before and after HV change, constrain models of gain vs HV Accuracy Goals 0.1 pulse height bin Scheduling & Special Requirements Immediately before and immediately after the HV change Changes from Cycle 20 No changes from Program

22 Purpose Description COS Target Acquisition Monitor P.I. Steve Penton Measure/monitor the WCA-to-PSA and WCA-to-BOA offsets used for target acquisitions (both IMAGING and SPECTROSCOPIC). There are four NUV ACQ/IMAGE mechanism combinations: 2 science apertures (SAs: PSA & BOA) x 2 mirror modes (MIRRORA & MIRRORB).. During SMOV, the WCA-to-PSA+MIRRORA offset was determined by an aperture scan; the other WCA-to-SA offsets were bootstrapped from this offset. Recent changes in the PSA+MIRRORA-to-PSA+MIRRORB offset were detected in the Focal Plane Calibration (SI-FGS Alignment) program (13171 for C20). This motivates the need to monitor all WCA-SA offsets. Hence, this program repeats the SMOV process for ACQ/IMAGE co-alignment, with the addition of the WCA-BOA offsets. In addition, this programs obtains PSA and BOA spectra of the targets to track any changes in the spectroscopic WCA-to-SA offsets. Fraction GO/GTO Programs Supported 100% of COS total exposure time (all COS exposures depend on WCA-SA offsets) Resources Required: Observations Resources Required: Analysis Products Accuracy Goals Scheduling & Special Requirements 2 external one-orbit visits + 4 external orbit contingency visit. The PSA+MIRRORA and PSA+MIRRORB coalignment is periodically tested in the SIAF file verifications of HST program, If for some reason this program has not been run with the current SIAF file, a contingency visit would be needed to measure the PSA +MIRRORA-to-PSA+MIRRORB offset. If more than 1 SIAF update occurs in C21, we will need 3 additional external orbits. 3 FTE weeks for analysis, creating new offsets, and writing an ISR. Updated NUV imaging WCA-to-SA offsets, NUV & FUV Spectroscopic WCA-to-SA offsets, summary in end of cycle ISR Imaging WCA-to-SA offsets need to be known to better than 0.5 NUV pixels in both dispersion and crossdispersion (XD). Spectroscopic WCA-to-SA offsets need to known to 0.5 XD pixel. Should be executed annually and after each COS SIAF adjustment. Changes from Cycle 20 None 22

23 Purpose Description Fraction GO/GTO Programs Supported Observations COS NUV Spectroscopic Sensitivity Monitor PI: Azalee Bostroem Monitor sensitivity of each NUV grating mode to detect any change due to contamination or other causes. The NUV gratings on COS are known to degrade with a rate which has been fairly steady since the start of on-orbit operations, with the bare-aluminum grating degrading at a faster rate than the MgF coated gratings. Additionally, track the time dependence of the sensitivity as a function of wavelength. Obtain exposures in all NUV gratings G230L, G185M, G225M, and G285M 3 times a year. We will monitor the following modes: G230L/2635, G230L/2950, G185M/1786, G185M/1921, G225M/2186, G285M/2617, and G285M/3094. These central wavelengths constitute the reddest and bluest central wavelengths containing only first order light with the exception of the G225M which was unused in Cycles 19 and 20 and is minimally used in Cycle 21. NUV usage continues to be minimal and the trends are stable, therefore we will continue to monitor the central wavelengths used in previous cycles. 12% of COS exposure time 6 external orbits Analysis Products Accuracy Goals 5 FTE weeks Time-Dependent Sensitivity Reference File and a summary in the end of cycle ISR. As permitted by resources and data quality: add wavelength dependence to TDS reference files SNR of 30 per resel at the central wavelength except for G285M with SNR 26 per resel (to fit in 1 orbit) Scheduling & Special Requirements Space observations at 4 month intervals Changes from Cycle 20 None 23

24 COS NUV Detector Dark Monitor P.I. Justin Ely Purpose Description Fraction GO/GTO Programs Supported Observations Perform routine monitoring of MAMA detector dark current. The main purpose is to look for evidence of a change in the dark, both to track on-orbit time dependence and to check for a developing detector problem. Monitor the NUV detector dark rate by taking TIME-TAG science exposures without illuminating the detector. Twice every other week a 22-min exposure is taken with the NUV (MAMA) detector with the shutter closed. The length of the exposures is chosen to make them fit in Earth occultations. All orbits < 1800s. 12% of COS total exposure time. 52 internal orbits Analysis 4 FTE weeks Products Provide ETC and IHB dark rate estimates, along with weekly monitoring for changes and a summary in the end of cycle ISR. As allowed by resources and necessitated by data quality: update bad-pixel tables. Update monitor webpage Accuracy Goals 15% Scheduling & Special Requirements Twice every other week, in earth occultation Changes from Cycle 20 None 24

25 NUV Dark Current Plots In ETC for C21: 9.92e-4 cts/pix/s Spatial Variation All darks to date 25

26 COS NUV Internal to External Wavelength Scale Monitor P.I. Paule Sonnentrucker Purpose This program monitors the offsets between the wavelength scale set by the internal wavecal versus that defined by absorption lines in external targets. Description Fraction GO/GTO Programs Supported Observations This program monitors the offsets between the internal and external wavelength scales: this offset is referred to as DELTA in the wavelength dispersion reference file and corrects for the shift between the WCA and PSA in TV03 versus the shift between the WCA and PSA in orbit: (WCA-PSA)_TV03 - (WCA-PSA)_orbit. Analysis of TV data indicates that this DELTA is cenwave and FP-POS independent for a particular grating, but it is grating and stripe dependent. To verify and monitor this, this program observes some cenwaves at different FP-POS. All orbits > 1800s. 12 % of COS total exposure time. 3 external orbits and all orbits > 1800s. Analysis 3 FTE weeks Products Update to wavelength dispersion reference file as needed and a summary in the end of cycle ISR. Accuracy Goals Scheduling & Special Requirements G230L 175km/s, pixels G185M 15km/s, pixels G225M 15km/s, pixels G285M 15km/s, pixels These observations are taken every 4 months. Changes from Cycle 20 No changes 26

27 COS NUV Focus Sweep PI: David Sahnow Purpose Description Fraction GO/GTO Programs Supported Observations Analysis Verify the focus of the COS NUV channel. This will be used to verify that the focus of the whole instrument (NUV and FUV) has not changed since SMOV, and will also serve as a baseline focus measurement if a switch to Side 2 is required. Take PSA+MIRRORA exposures at different NUV focii, spaced evenly between +/-200 steps, in order to obtain a focus curve. This was previously done as part of Program in SMOV, and is included in Program (COS NUV Side 2 Initial NUV Channel Checkout). ISR describes the SMOV results. 100% (This program determines the focus for the whole instrument) 1 external orbit 1FTE week (Existing IDL programs will be used to measure the FWHM of the as a function of focus position, plus documentation) Products Plots of spot FWHM as a function of focus position. Accuracy Goals 50 focus steps Scheduling & Special Requirements None. The target is available all year. Changes from Cycle 20 New program 27

28 SMOV results Enclosed energy FWHM 28

29 Motivation Carbon fiber structure shrinks on orbit with outgassing We need a baseline focus measurement for the whole instrument in case we need to switch to side 2 May need to be repeated every couple of years 29

30 COS NUV MAMA Fold Distribution P.I. Thomas Wheeler Purpose Description Fraction GO/GTO Programs Supported Observations The fold analysis provides a measurement of the distribution of charge cloud sizes incident upon the anode providing some measure of changes in the pulse-height distribution of the MCP and, therefore, MCP gain. While globally illuminating the detector with a flat field, the valid event (VE) rate counter is monitored while various combinations of row and column folds are selected. 12% of COS exposure time 1 internal orbit Analysis 0.5 FTE day. Products The results will be sent to the COS Team and V. Argabright. Accuracy Goals Scheduling & Special Requirements This proposal is executed annually. Changes from Cycle 20 None 30

31 Contingency programs 31

32 COS FUV Recovery after Anomalous Shutdown P.I. Thomas Wheeler Purpose Description Fraction GO/GTO Programs Supported Observations The safe and orderly turn-on and ramping-up of the COS FUV high voltage in a conservative manner after a HV anomalous shutdown. Day 01 activities, visits 01-07, contain both QE grid off and on HV ramping to HVLow (100/100) with diagnostics (DCE dumps) and darks to exclude QE grid involvement in the shutdown. Subsequent to day 01, all HV rampings, diagnostics and darks will be with the QE grid on. The HV commanded values for the subsequent days are: 154/151, 160/157, 167,163, ect. until the desired HV is obtained. 88% of COS exposure time 17 internal orbits Analysis If activated, 0.5 FTE day per test. Products After thorough data analysis for each test day, a Go/No-Go to proceed will be given. Accuracy Goals Scheduling & Special Requirements This is a contingency proposal activated only in the event of an anomalous shutdown. Changes from Cycle 20 None 32

33 COS NUV Detector Recovery after Anomalous Shutdown P.I. Thomas Wheeler Purpose Permit a safe and orderly recovery of the NUV-MAMA detector after an anomalous shutdown. Description Fraction GO/GTO Programs Supported Observations The recovery procedure consists of four separate tests (i.e. visits) to check the MAMA s health after an anomalous shutdown. Each must be successfully completed before proceeding onto the next. They are: (1) signal processing electronics check, (2) slow, intermediate voltage high-voltage ramp-up, (3) ramp-up to full operating voltage, and (4) fold analysis test. 12% of COS exposure time 4 internal orbits Analysis Products If activated, 0.5 FTE day per visit. For tests 1-3, only a Go/No-Go to proceed will be given. For test 4, the results will be sent to the COS/STIS Team and V. Argabright. Accuracy Goals Scheduling & Special Requirements This is a contingency proposal activated only in the event of an anomalous shutdown. Changes from Cycle 20 None 33

34 C21 supplemental calibration programs Programs supporting the next lifetime move: o o Limited number of exploratory programs to explore the feasibility of moving as close as possible to LP1 Similar to what was done in C20, we will need enabling and calibration programs before and after the move to lifetime position 3. The number of orbits for these programs is not yet determined. Program to investigate the dependency of the FUV sensitivity on HV (at LP2) 34

35 COS Side 2 programs Programs will be carried along each cycle s calibration plan (keeping the same ID) so that the impact of any changes to operating conditions (e.g., gyros) can be evaluated and modifications to the programs implemented as needed Engineering programs o COS Side 2 Dump Test and Verification of COS Memory Loads - J. Bacinski o COS Side 2 Science Data Buffer Check/Self-Tests for CS Buffer RAM and DIB RAM - J. Bacinski o COS Side 2 NUV Detector Recovery After MEB Side Switch - J. Bacinski o COS Side 2 FUV Detector Recovery After MEB Side Switch - J. Bacinski o COS Side NUV MAMA Fold Test - J. Bacinski Science programs o COS Side 2 Initial NUV Checkout - D. Sahnow o COS Side 2 Initial FUV Checkout - R. Osten o COS Side 2 Internal NUV Wavelength Verification - S. Lockwood 35 o COS Side 2 Internal FUV Wavelength Verification - S. Lockwood

36 Backup 36

37 NUV Internal to External Wavelength Scale Monitor P.I. Paule Sonnentrucker Purpose This program monitors the offsets between the wavelength scale set by the internal wavecal versus that defined by absorption lines in external targets. Description Fraction GO/GTO Programs Supported Observations This program monitors the offsets between the internal and external wavelength scales: this offset is referred to as DELTA in the wavelength dispersion reference file and corrects for the shift between the WCA and PSA in TV03 versus the shift between the WCA and PSA in orbit: (WCA-PSA)_TV03 - (WCA-PSA)_orbit. Analysis of TV data indicates that this DELTA is cenwave and FP-POS independent for a particular grating, but it is grating and stripe dependent. To verify and monitor this, this program observes some cenwaves at different FP-POS. All orbits > 1800s. 12 % of COS total exposure time. 3 external orbits and all orbits > 1800s. Analysis 3 FTE weeks Products Update to wavelength dispersion reference file as needed and a summary in the end of cycle ISR. Accuracy Goals Scheduling & Special Requirements G230L 175km/s, pixels G185M 15km/s, pixels G225M 15km/s, pixels G285M 15km/s, pixels These observations are taken every 4 months. Changes from Cycle 20 No changes 37

38 Justification of cadence One additional data point to confirm the increasing zeropoint offset for G185M, G225M, and G285M (1pixel/year). o Implementation of the change in reference file would result for these data One additional data point (for a total of 5 from C17 to C21) to confirm the apparent temporal trend seen in the May visits for G185M, G225M, and more subtly for G285M over the past 2 cycles. 38

39 Justification (C18 results) 39

40 Justification (C19 results) 40

41 PtNe #1 Status Based upon ground testing, each lamp is predicted to last between 7-10 Amp-hours (A-h). Running at the medium current level of 10mA, this is hours of usage. To date, PtNe#1 has been used for 188,000 seconds of lamp exposure (52 hours, ~0.52 A-h). Additionally, ~1 A-h was used during ground testing. o PtNe #1 has been used for 15-20% of its lifetime. However, PtNe#1 may be aging faster than the ground tests predicted. 41

42 NUV TDS 42