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GLM FM3 and FM4 Status Marc Rafal Instrument Manager GOES-R Flight Project

GLM FM3 and FM4 Status Marc Rafal Instrument Manager GOES-R Flight Project. U.S. Export Controlled Information:

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GLM FM3 and FM4 Status Marc Rafal Instrument Manager GOES-R Flight Project

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  1. GLM FM3 and FM4 Status Marc RafalInstrument ManagerGOES-R Flight Project U.S. Export Controlled Information: Information included herein is controlled under the International Traffic in Arms Regulations (ITAR) by the U.S. Department of State. Transfer of this information to a Foreign Person or foreign entity requires an export license by the U.S. State Department or an ITAR exemption to the license requirement prior to the export or transfer.

  2. What a long strange trip its been • FM3 completed instrument level I&T and was installed on GOES-T January 2018 • Capacitor failures during FM4 instrument level TVAC led to concern about reliability of Lot 1134-AY ceramic capacitors • Reach back to FM3 SU (not EU) • Flight Project directed actions to mitigate risk • Extensive testing of Lot 1134-AY and Lot 1318-AH (used in SN5 boxes) • Return FM3 SU to Palo Alto for additional “burn-in” operating hours (EU remains installed on GOES-T) • FM3 SU Burn-in resulted in excess noise anomaly • Root cause isolated to Horizontal board in FPAA • Presumed to be failed capacitor. Investigation on-going. • Capacitor investigation • Subpopulation of 1134-AY capacitors fail in first few hundred hours, remainder have adequate reliability • Extensive life testing demonstrate reliability of 1318-AH capacitors • Flight Project directed that FM3 SEB and FPAA be replaced with SN5 (Spare) boxes that do not contain 1134-AY capacitors • Remainder of FM3 SU is unchanged

  3. Current Status • FM3 Rebuild (FM3R) reintegration complete using spare FPAA and SEB boxes that do not contain suspect capacitor lot • TVAC started 9/3 • Interrupted due higher than expected FPAA temperature • Issue with thermal conduction at interface between heat pipe and FPAA • No evidence that Loop Heat Pipe performance is an issue • Investigation underway • Shipment to Denver schedule for March 2020 • FM3R (and FM4) incorporate design changes from FM1 and FM2 • Stray light mitigation will reduce impact of solar intrusion during eclipse season • Overshoot mitigation will reduce “rebound” false events • Unintended consequence of gain compression at brightest background levels U.S. Export Controlled Information

  4. Gain Compression This graph shows how one 30x30µm pixel responds to light Dotted line: FM1-like response Event magnitude in bright conditions (high radiance) No detection Equivalent radiance increment from the same example lightning pulse Under high illumination, the response to the same lightning pulse is too small to trigger a detection Worst-case cloud radiance Event magnitude in dark conditions (low radiance) Event detection Equivalent radiance increment from example lightning pulse Export Controlled Information

  5. Pixel Pitch Boundaries East Position West Position 30x30 µ Pixels

  6. Performance Impact Conclusions • DE performance loss due to noontime saturation is nearly certain • Occurs only on high albedo clouds • Occurs primarily in largest 30 x 30 µm pixels, but can also affect smaller pixels such as over southern CONUS • Magnitude of the short term DE loss • CONUS: 2% flash DE loss • Full Disk: 11% flash DE loss • 30 x 30 µm pixels: 13% flash DE loss • Duration of the effect is a few hours around noon • Clouds are Lambertian reflectors, so their radiance goes as cosine of solar zenith angle • Cosine of solar zenith angle remains close to 1.0 for several hours • At other times of the day, this saturation effect is not present

  7. FM4 Status • FM4 EU is installed on GOES-U spacecraft • Does not contain capacitors from suspect lot • Primary path for FM4 SU is to requalify electronics boxes for flight • FPAA and SEB contain suspect lot capacitors • Box level “Burn-in” testing to put 1000 hours per side • Capacitor testing suggests “bad” capacitors fail after first few hundred hours • Surviving capacitors have nominal reliability • SN4 FPAA and SEB box level burn-in starts this week and extends into December • Backup paths available • SN3 SEB has already seen 1000 hours per side • SN3 FPAA requires new CCD detector – spares being evaluated • Parts ordered for additional spare boards

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