01/15/2004 TIPS/JIM Summary of the JWST Mission and Observatory Systems Requirements Reviews, and Micro-Shutter Array (MSA) Confirmation Review Jerry Kriss

01/15/2004 TIPS/JIM SRR Objectives  Confirm that mission-level and observatory requirements meet the project objectives  Confirm observatory-level specifications are sufficient to meet the project objectives  Validate that the mission architecture concept can support the functional, operational, interface and performance requirements  Show that the requirements have been flowed down and are understood at the next level.

01/15/2004 TIPS/JIM SRR Review Team Dennis Dillman, ChairGSFC System Review Office Steve GrahamGSFC Project Management Alain BerinstainCSA Ted HarperCSA Jacques LouetESA Colin JonesESA Steve ScottGSFC Chief Engineer Alexander KrimchanskyGSFC Gene WaluschkaGSFC Optics Sachi BabuGSFC Detectors Tom McCarthyGSFC Thermal Mark FontaineGSFC Joe SchepisGSFC Electromechanical Peiman MaghamiGSFC Minh PhanGSFC Dr. Mal Niedner GSFC Space Sciences

01/15/2004 TIPS/JIM NIRCam SRD NIRSpec SRD MIRI SRD FGS SRD JWST Requirements Tree JWST-ICD JWST-ICD JWST Program Plan JWST-PLAN Program System JWST Performance Assurance Requirements JWST-RQMT JWST Science Requirements Document JWST-RQMT JWST Mission Operations Concept Document JWST-OPS Segment Performance Quality Assurance Plan JWST-PLAN Contamination Control Plan JWST-PLAN JWST Observatory Specification JWST-SPEC Environmental Req’s for the JWST Observatory JWST-SPEC EMC Control Plan JWST-PLAN WFS&C Requirements Allocation Document JWST-RQMT Ground Segment Requirements JWST-RQMT JWST System Verification Plan JWST-PLAN Launch Segment Specification JWST-SPEC Flight Observatory to Ground Segment IRD JWST-IRD Observatory to Launch Segment IRD JWST-IRD NIRCam OCD NIRSpec OCD MIRI OCD FGS OCD Radiation Requirements Allocation Specification JWST-SPEC ISIM to OTE and JWST-ICD Fault Protection Requirements Document JWST-RQMT ISIM to OTE and Spacecraft IRD JWST-IRD OTE Specification JWST-RQMT SC Requirements Document JWST-RQMT ISIM Requirements Document JWST-RQMT Element Spacecraft to OTE ICD D35231 L1 SR JWST Mission Requirements JWST-RQMT MRMOCPA GS OBS ISIM EV RD WFS CCP PQ EMC OL OLC LS FP FG FGC IOS-IR IOSC OTE SOIC SC Baselined In CM Review Drafts Available Allocation Documents Budgets WFE Rev Q 03-JWST-0405 Efficiency Pointing D36128 Observatory to GSE IRD D36127 OG OGC Observatory I&T Plan JWST-PLAN

01/15/2004 TIPS/JIM JWST Science Requirements (John Mather presenting)  Four themes: First Light Assembly of Galaxies Birth of Star and Planetary Systems Planetary Systems and the Origins of Life  Level 1 Mission Success Criteria: Density of galaxies Spectra of galaxies Physical and Chemical properties of young stellar objects Observing time---5 yr mission, 1.1e9 s on target Telescope > 25 m 2 Strehl ratio > 0.8 at 2  m Encircled energy > 0.74 within 0.15 arc sec at 1  m, stable for > 24 hrs. Thermal environment zodi limited  m  Example of how Level 1 requirements flow down: 1 st -light objects are rare ( large, unvignetted FOV with low distortion.

01/15/2004 TIPS/JIM Requirement Changes Since the Delta-MDR  Redesigned sun shield---smaller, better clearances, simpler deployment – but, it could make mission planning more difficult.  Upgrade the power system to accommodate ISIM power needs.

01/15/2004 TIPS/JIM Requirements Still in Work  Moving targets. Quantitative requirements are TBD, depending on cost.  Sensitivity. New numbers developed, but CCB on hold pending NGST replan contract change.  Mass allocations are TBD pending resolution of the ISIM Electronics Compartment (IEC) study.  Ariane 5 change not yet flowed down (no expected impact).  FOV offsets not yet flowed done (no expected impact).  Reliability. Recent MRD change says goal is 92% for Spacecraft+OTE. Goal for whole observatory is pending.  OTE to ISIM structural interface definition.  X vs. Ka-band study. [Should finish soon in favor of Ka.]

01/15/2004 TIPS/JIM Key Issues  Concept for locating ISIM electronics in Region 2 is not viable. FPEs must be within 6m of focal planes, in Region 2 Adding ICE boxes advantageous "Saddle-bag" configuration won't work. (Too massive; thermal problems.) Further work underway. (IEC trade study. Will take FPE rqmnts into account.)  Mass Allocations Current mass reserves are at 21%. Would like to be at 25%. Biggest problem areas are the IEC accommodation, and the sun shield containment system. Spacecraft is 250 kg over its allocation OTE is 405 kg over its allocation MIRI dewar is 20 kg over its allocation; NIRCam is 7 kg too heavy.

01/15/2004 TIPS/JIM (ISIM Region 1) (ISIM Region 2) (ISIM Region 3)

01/15/2004 TIPS/JIM SRR Summary Results  The board thought that the review was excellent.  ~60 Requests for Action (RFAs) generated.  Major issues in the RFAs: Request for an Observatory-level TV test. Request for deployment tests in TV. Desire to make several of the Mission/Obs rqmnts less vague and more verifiable (e.g., those related to event- drive ops). Need to do a better flow down of the efficiency rqmnt and tie it in to data quality and reliability in a more comprehensive way. Fault handling requires more development.

01/15/2004 TIPS/JIM Micro-Shutter Array (MSA) Confirmation Review  Held 12/18/03 at GSFC to assess whether the MEMS micro- shutter array should be the slit-defining mechanism for NIRSpec.  Successes: Fabricated 128 x 64 arrays (flight will be 384 x 175) Demonstrated 2-D addressing Implemented light shields Performed cryogenic life tests Measured pixel failure rate at end-of-life Measured open/closed shutter contrast ratio [2, ,000 warm; ~200 cold (due to shutter curvature)] Performed an acoustic test

01/15/2004 TIPS/JIM MSA Backside 100  m Magnetic Stripes on MSA Frontside 20  m MSA Light Shields 100  m

01/15/2004 TIPS/JIM Micro-Shutter Array (MSA) Confirmation Review  Concerns: Yield is still low Light shields frequently break off Shutters curve and bend when cooled Life testing does not meet <10% of rows with a failed- open shutter Crude acoustic/shake tests increase rate of failed-opens  Further development needed, but optimism prevails.  The MSA remains the preferred approach, and the European selection is proceeding on this basis.