Mission concerns we are watching
• Mass – Mission was exceeding mass allocations. Potential solutions could have had
operational impacts. Solutions now appear benign (incl. new Arianne lift capability).
• Pointing Transients – Variety of pointing issues had potential science impacts (e.g.,
coronagraphic and NIRSpec/MSA programs). Mitigations (slew control laws, fuel tank
baffles, star tracker redesign) underway.
• FGS FSW – Major issues with fundamental functions when first delivered. Our staff
played major role in discovery & characterization. Updates have resolved
fundamental problems. Pursuing tests of more complex observing situations.
• Stray light – Increases in temperatures of primary mirror and observatory core are
causing mid-infrared stray light levels to exceed requirements. Some mitigations
(e.g., changing the OTE bib) will help, but the outcome and impacts remain unclear.
• NIR Detectors – Degradation of the original near-IR detectors. Development of
replacement flight parts with a new design. Yield higher than expected. New parts
appear superior with the exception of intermittent “snow balls.”
• MIRI Sensitivity – Acceptance review went well. Several concerns, including MRS
Channel 4 throughput and decreased sensitivity at all wavelengths. FRB concluded
that required MIRI sensitivity could be reached through appropriate data reduction
and operational approaches. Several potential paths forward. Looking for most
operationally efficient approach.
Mission concerns we are watching
• Mass – Mission was exceeding mass allocations. Potential solutions could have had
operational impacts. Solutions now appear benign (incl. new Arianne lift capability).
• Pointing Transients – Variety of pointing issues had potential science impacts (e.g.,
coronagraphic and NIRSpec/MSA programs). Mitigations (slew control laws, fuel tank
baffles, star tracker redesign) underway.
• FGS FSW – Major issues with fundamental functions when first delivered. Our staff
played major role in discovery & characterization. Updates have resolved
fundamental problems. Pursuing tests of more complex observing situations.
• Stray light – Increases in temperatures of primary mirror and observatory core are
causing mid-infrared stray light levels to exceed requirements. Some mitigations
(e.g., changing the OTE bib) will help, but the outcome and impacts remain unclear.
• NIR Detectors – Degradation of the original near-IR detectors. Development of
replacement flight parts with a new design. Yield higher than expected. New parts
appear superior with the exception of intermittent “snow balls.”
• MIRI Sensitivity – Acceptance review went well. Several concerns, including MRS
Channel 4 throughput and decreased sensitivity at all wavelengths. FRB concluded
that required MIRI sensitivity could be reached through appropriate data reduction
and operational approaches. Several potential paths forward. Looking for most
operationally efficient approach.
Mission concerns we are watching
• Mass – Mission was exceeding mass allocations. Potential solutions could have had
operational impacts. Solutions now appear benign (incl. new Arianne lift capability).
• Pointing Transients – Variety of pointing issues had potential science impacts (e.g.,
coronagraphic and NIRSpec/MSA programs). Mitigations (slew control laws, fuel tank
baffles, star tracker redesign) underway.
• FGS FSW – Major issues with fundamental functions when first delivered. Our staff
played major role in discovery & characterization. Updates have resolved
fundamental problems. Pursuing tests of more complex observing situations.
• Stray light – Increases in temperatures of primary mirror and observatory core were
causing mid-infrared stray light levels to exceed requirements. However, current
analysis has stray light at both 10 and 20 microns within requirements, due to:
 Realistic assumptions regarding dust distribution & emissivity on mirror
• NIR
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the original
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Development of
 Detectors
Extending –the
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portions
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replacement
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Yieldblocked
higher than
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New parts
 Deployable
tower
assembly
nowdesign.
completely
by bib
& sunshield
appear superior with the exception of intermittent “snow balls.”
• MIRI Sensitivity – Acceptance review went well. Several concerns, including MRS
Channel 4 throughput and decreased sensitivity at all wavelengths. FRB concluded
that required MIRI sensitivity could be reached through appropriate data reduction
and operational approaches. Several potential paths forward. Looking for most
operationally efficient approach.