nirspec status and pdr results jeff valenti & mike regan 2006 march 16 tips/jim

NIRSpec Status and PDR Results

Jeff Valenti & Mike Regan

2006 March 16

TIPS/JIM

Light Path

PDR Objectives

Assess compliance with requirements Assess NIRSpec system specifications Assess external interface definitions

Integrated Science Instrument Module Microshutter Array Detector Subsystem

Assess predicted NIRSpec performance Assess cost, schedule, and risk estimates

PDR Format

Board Led by ESA with NASA participation Co-chaired by NASA Independent Review Office

Technical Panels System Structure, thermal, and mechanisms Optics Electrical and software Product Assurance

Programmatic Panel

PDR Timeline

Dec 1 Documents delivered Dec 2 Kick-off meeting held … Panel meetings … Jan 6 Panel chairs met

“Review Item Dispositions” submitted Jan 31-Feb 2 Co-location

ESA/Industry ESA/Instrument Science Team

Feb 9 Panel chairs reported to board Feb 15 Board met

PDR Verdict

NIRSpec PASSED its PDR!

PDR Major Findings

Microshutter technology is a risk Electrostatic discharge is a risk Create stray light control plan Include detector in EMC control plan Cool light sources used in ground tests Prevent contamination by water Manage target acquisition interfaces Test cold after observatory integration

No Schedule Change

JWST launch date slipped to June 2013 NIRSpec delivery date is unchanged

Necessary to control ESA costs Requires timely definition of interfaces Requires timely delivery of subsystems NASA funding ISIM to support schedule

Microshutter Update

Technology demonstration tests Lifetime test: <5% shutters fail after 105 cycles Acoustic test: <1% shutters fail Vibration test: <1% shutters fail Radiation test: <1% shutters fail Open/closed contrast: >2000 EMC/EMI test Demonstrate ability to plug shutters in lab

Stiction issue 0.5% shutter stuck open after 105 cycles Heating to 300 K causes shutter release

Rogue Path Update

Unbaffled telescope

Sky skirts FSM and illuminates POM

NIRSpec wants 9 mm increase in FSM mask

NIRCam coronagraph blocked by >6 mm

Outer edge of FSM mask

Inner edge of NIRSpec mask

Orders of Magnitude in Scale

10 10

10

4365171250K Shutters

Q1 Q2

Q3 Q4

Plate Scale Changes

We must position targets in shutters

Allocate 5 mas for plate scale changes

Corresponds to 0.01% change in focal length

Rephase primary as often as once a week