TEMPO Instrument Update Brian Baker, TEMPO Performance Brent Canova, GEMS/TEMPO CSE TEMPO Science Team Meeting May 27-28, 2015 bdbaker@ball.com

Ball TEMPO Program Status Instrument design is maturing with CDR in June 2015 Performance estimates have been updated based on design maturity Updating performance estimates with expected “as manufactured” performance. Instrument performance TIM held May 12, 2015 At NASA KDP-C Instrument cost risk was perceived to be too high Ball agreed to convert contract from Cost Reimbursable to Fixed Price SAO, LaRC and Ball to continue to work together to control and avoid costs Project is still cost-capped Ball participated in Host Accommodation Study Multiple options for hosting TEMPO on commercial comm sats Timing of launch opportunities poses some risk of delay for TEMPO mission 5/21/2014

TEMPO Design Maturation Since Last Science Meeting Pre-CDR Design as of 5/2015 Design Presented at 7/2013 Science Team Meeting Pre-PDR Design as of 5/2014 Entrance Baffle Sensor Heat Sink Scan Mechanism FPE Composite Structure CMA FPA Thermal Interface 5/21/2014

TEMPO Instrument: Host Mounting & Expanded View 9/22/2018

Design Changes Since PDR Optical bench design changes for launch loads Improved invar joints that are used to bond composite members Additional composite supports Updated thermal design for host accommodation TEMPO radiators replaced with spacecraft controlled heat sinks FPA heat pipe has been replaced by a conduction bar that interfaces directly to the host thermal interface EDU and Flight Hardware is being built and tested 9/22/2018

Hardware Updates Diffraction grating EDUs manufactured and tested Flight calibration wheel in process Scan mechanism gimbal carrier Calibration wheel housing in process EDU Electronics and SWTB completed 9/22/2018

Hardware Updates EDU FPA and FPE board Flight trusses And invar fittings Flight Diffuser Material EDU CMA Actuator 9/22/2018

TEMPO Parameter Evolution SRR Value PDR Baseline CDR Notes Frame Integration Time 95.83 ms 118 ms No change since PDR Image Frame Rate 10 Hz 8.19 Hz 7.92 Hz Increase in frame transfer time from 4.17 ms to 8.33 ms to mitigate CCD current spike concerns. Image Frame Time 2.70 s 2.69 s 2.65 s Includes integration time, frame transfer time, and coadds. Number of Coadds 27 22 21 Scan Mirror Step Size 115 urad 114 µrad Number of Scan Mirror Steps 1267 1278 1282 Added four additional mirror steps (two at the beginning of scan, two at the end of scan) to mitigate slit curvature effects and ensure spatial coverage performance. Coverage Time 59.14 min 59.39 min 59.1 min Updates with CDR parameters 5/21/2014

SNR The TEMPO radiometric model has undergone several changes since PDR, including: Updates to coverage time calculation. Increased the frame transfer time from 4.17 ms to 8.33 ms to mitigate CCD current spike issues. Updates were made to “Contamination and Radiation” tab based on updated contamination estimates. Updated the number of worst-case pixel transfers. Updated “Stray Light” tab to use the results of the broadband stray light analysis. Updated, Pixel saturation, Pixel photon shot noise, Smear noise, CTE noise to properly account for stray light Updated Detector full well, read noise and CTE values Updated all optical elements with predicted performance curves from the optics suppliers Added input “Slit Curvature” and calculate the additional steps needed to compensate for slit curvature effects. These additional steps are added onto the total number of steps needed for compliance in the absence of slit curvature effects. SNR estimates assume the TEMPO EOL CTE as called out in the TEMPO FPS specification 5/21/2014

CCD Technical Challenges Measurements of TEMPO Lot 1 CCD Charge Transfer Efficiency (CTE) are below expectations CTE measurements indicated that regions with low signal levels would have very poor charge transfer efficiency Science implications: data quality at short wavelengths would be compromised Collaboration between BATC detector experts and Dalsa have identified the most likely root cause Two mitigation steps were taken Lot 3B design – eliminate the areas with the 3-poly overlap, which is where the low CTE was observed Lot 4A design – eliminate one poly layer altogether to create a 2-poly device Lot 3B and Lot 4A devices are in-house and CTE measurements are in-process Measurements of TEMPO Lot 1 CCD dark current rates are below expectations Measured dark current rates are 5-10x higher than initially expected Science implications: reduced SNR performance (primarily at shorter wavelengths), larger dark current correction errors for on-orbit operations Collaboration between BATC detector experts and ITL have led to deeper understanding of the sources of dark current in the Lot 1 CCDs Several mitigation steps are being explored There will be some capability to run the CCDs slightly colder on-orbit Changes to the FPE could result in a small (~20%) reduction in CCD dark current ITL is investigating their process to reduce dark current 5/21/2014

SNR Requirements vs Performance: Two Scenarios SNR performance is shown here for two scenarios: “CDR SNR” = TEMPO SNR with FPS specification dark current “Worst-Case” = TEMPO SNR with worst-case measured dark current and the minimum specified system throughput Both SNR scenarios have CCD temperature at -17° C Both SNR scenarios have a coverage time = 59.1 minutes Wvl (nm) EV SNR Reqmt CDR SNR Margin Worst-case Dark current SNR Margin 290 19.6 36 82% 19.0 -3% 300 46.1 83 79% 45.5 -1% 305 161.9 257 59% 165.6 2% 310 377 546 45% 405.1 7% 320 1220 1623 33% 1394.6 14% 330 2003 2629 31% 2323.4 16% 340 2013 2613 30% 2338.1 350 1414 2427 72% 2209.8 56% 420 836 1893 126% 1636.6 96% 430 675 1503 123% 1306.8 94% 450 733 1521 108% 1416.2 93% 490 1176 1395 19% 1294.2 10% 540 1109 1374 24% 1225.5 11% 600 987 1237 25% 1091.6 650 898 1137 27% 995.2 690 820 965 18% 903.9 5/21/2014

KTP Summary: Science Performance (1 of 3) Reqt This Month Last Month Trend Notes Bandwidth < 0.6 nm 0.599 nm 0.576 nm ↑ 3-σ Roll-up Bandwidth Symmetry < 6% ≤ 6% No Change Radiometric Calibration Accuracy < 4% (1-sigma) 3.78% (1-sigma) Radiance at 290 nm 3.16% (1-sigma) Radiance at 300 nm / 2.99% (1-sigma) Irradiance Radiance Stray Light 300 nm: < 30% 310 nm: < 15% 320 – 740 nm: < 5% 300 nm: 6.1% 310 nm: 1.6% 320 – 740 nm: ≤ 1.2% Albedo Stray Light 300 nm: < 15% 310 – 740 nm: < 3% 300 nm: 5.2% 310 – 740 nm: < 1% Structured Stray Light < 5e-4 5/21/2014

KTP Summary: Science Performance (2 of 3) Reqt This Month Last Month Trend Notes FOR 4.61° N/S FOR (derived) 8.35° E/W FOR (derived) 4.76° N/S FOR 8.951° E/W FOR 4.75° N/S FOR 9.16° E/W FOR ↑ ↓ 3-σ Roll-up GSD ≤ 2.22 km, ≤ 5.15 km @ C.F.* 2.21 km, 4.97 km @ C.F.* 2.13 km, 4.50 km @ C.F.* ↑, ↑ E/W Step Overlap 6 µrad No Change MTF > 0.16 @ 0.5 cyc/N-S GSD > 0.3 @ 0.5 cyc/E-W GSD 0.19 @ 0.5 cyc/N-S GSD 0.44 @ 0.5 cyc/E-W GSD 0.187 @ 0.5 cyc/N-S GSD Spectral Sampling ≥ 2.7 pixels / FWHM 2.9 pixels / FWHM LPS 290 – 490 nm: < 5% (1-sigma) 540 – 690 nm: < 20% (1-sigma) 290 – 490 nm: < 4% (1-sigma) 540 – 690 nm: < 15% (1-sigma) SNR See SNR chart See following slides Alignment Knowledge (0th, 1st, 2nd, 3rd +) 0th: < 40 µrad over 1 hour, 1st: < ±0.0015 over one orbit , 2nd: < ±0.01 /rad over one orbit, 3rd +: < 20 µrad (3σ) over FOR 10.28 µrad 0.0008 0.006 / rad 23.80 µrad 30 µrad 0.0006 0.004 / rad 19 µrad 3-σ Roll-up; Mission has >15% margin on INR per Jim Carr INR TIM presentation Alignment Knowledge over Two Adjacent N-S Swaths < 2.5 urad (3-sigma, per-axis) 0.33 µrad 0.48 µrad * C.F. = Chance Farm at Geodetic 36.5° N, 100° W 5/21/2014

KTP Summary: Science Performance (3 of 3) SNR Wavelength Requirement SNR Performance This Month Last Month Trend Notes 290 19.6 36 No Change SNR estimate assumes 300 46.1 83 FPS spec EOL CTE and 305 161.9 257 dark current 310 377.0 546 320 1220.0 1623 330 2003.0 2629 340 2013.0 2613 350 1414.0 2427 420 836.0 1893 430 675.0 1503 450 733.0 1521 490 1176.0 1395 540 1109.0 1374 600 987.0 1237 650 898.0 1137 690 820.0 965 5/21/2014

Summary Instrument approach: CDR EDU hardware completed Flight hardware being manufactured Performance estimates show compliance, with one exception 3rd order alignment knowledge compliance has some challenges Working at instrument level to bring into compliance Mission-level INR performance still has >15% margin, despite instrument-level compliance status Instrument has contingency over all other requirements to ensure compliance of as built hardware Program is working through technical challenges Detector charge transfer efficiency Detector dark current Communicate early and often with NASA LaRC and SAO Team works together to mitigate risk and avoid cost 5/21/2014