JWST Project Status AAAC, October 12, 2005

1. JWST Project StatusAAAC, October 12, 2005 John C. Mather JWST Senior Project Scientist NASA GSFC

2. Topics • Science summary • Mission summary • Technology status • Test plan status • Contamination and Stray Light plan

3. How and from what were galaxies assembled? What is the history of star birth, heavy element production, and the enrichment of the intergalactic material? How were giant black holes created and what is their role in the universe? Three instruments to do this: NIRCam (NASA/CSA), NIRSpec (ESA), MIRI (ESA/consortium/NASA), plus FGS-TF (CSA) Top JWST Goal - Find the First Light after the Big Bang  as seen by COBE ? Galaxy assembly ? Galaxies, stars, planets, life

4. The Epoch of Reionization Redshift Neutral IGM . z~zi z<zi z>zi Wavelength Wavelength Wavelength Lyman Forest Absorption Black Gunn-Peterson trough Patchy Absorption

5. The Eagle Nebulaas seen in the infrared JWST Science • End of the dark ages: first light and reionization • The assembly of galaxies The Eagle Nebula as seen by HST • Birth of stars and protoplanetary systems • Planetary systems and the origins of life Galaxies in the UDF

6. R=100, 1-s 10,000 sec 4 3 2 Spectra obtained with the JWST MIRI on the nearest systems can provide detailed insights to the minerals in ring particles and the nature of giant planets 1 R=2000, 1-s 100 sec 0 mJy Simulated Vega Observation

7. Model Picture

8. Primary Mirror (PM) • 18 (1.315 m) hex segments • Simple semi-rigid WFS&C for phasing • 6 degree of freedom rigid body • Radius corrections • Deployable chord fold for thermal uniformity • ISIM • NIRCam, NIRSpec, MIRI & FGS • Enclosure for FPE • Simple Kinematic interface • Secondary Mirror (SM) • Deployable tripod for stiffness • 6 DOF to assure telescope alignment • Sunshield • Passive cool ISIM/OTE to ~40K • Limits momentum buildup • Tower • Isolates telescope from spacecraft dynamic noise • Spacecraft Bus • Isolates reaction wheel noise JWST Observatory Architecture • Optical Telescope Element (OTE) • Stable over total field-of-regard • Beryllium (Be) optics with GFRP/Boron structure • Performance verified on the ground

9. JWST Orbit about the Sun-Earth L2 and Launch Configuration

10. Ball AMSD II Be Mirror in Optical Test

11. Actuators for 6 degrees of freedom rigid body motion, independent of ROC control Actuator development unit Primary Mirror Segment Actuations Lightweighted Beryllium Mirror Substrate Observatory optical quality (mid and high spatial frequency) is manufactured into segments Actuator for radius of curvature adjustment

12. A NIRCam Imaging Module A dichroic allows simultaneous observing at two wavelengths. This module’s dual filter wheels include pupils for wavefront sensing.

13. HgCdTe NICMOS 256x256 WFC3 1024x1024 JWST Proto-type 4Kx4K Detector Technology Development • NICMOS and IRAC arrays have demonstrated the basic detector architecture but with lower performance and smaller formats. • TRL 4 achieved Feb 2002 with JWST performance levels achieved • TRL 5 achieved Feb 2003 with JWST size 2Kx2K devices, mosaicing • Astronomical Image with prototype, Sept. 2003 • Flight detectors being manufactured

14. NIRSpec: ESA & Astrium • > 100 Objects Simultaneously • 9 square arcminute FOV • Implementation: • 3.5’ Large FOV Imaging Spectrograph • 4 x 175 x 384 element Micro-Shutter Array • 2 x 2k x 2k Detector Array • Fixed slits and IFU for backup, contrast • SiC optical bench & optics

15. Micro-Shutter Array Grating/Prism Wheel Detector Array Filter Wheel Pick-off Optics Fore optics Collimator Camera NIRSpec Schematic

16. SAT Recommendations and Response

17. Technology Status • All technologies to be ready for by Non-Advocate Review (NAR) • Key technologies: • Mirrors - flight mirror blanks made and being machined; EDU being polished; operator error (due to an unexpected feature in the machine) at Axsys drilled hole in one blank, no effect on schedule • Detectors - TRL 5 achieved in 2003, all performance specifications met; some HgCdTe detectors disintegrated, apparently due to insufficient cleaning prior to bonding to BCS (Balanced Composite Substrate); new recipe verified by repeated thermal cycles • Microshutters - GSFC - recipe found for keeping shutters flat at room temperature and cold; on track with all needed tests • ASICs - all performance specifications met; final foundry run starting with revised masks • Cryocooler - will select contractor in January

18. Baseline “Cup Down” Tower Configuration at JSC (Before) Most recent Tower Design shows an Inner Optical Tower supported by a Outer structure with Vibration Isolation at the midplane. Everything shown is in the 20K region (helium connections, etc. not shown) except clean room and lift fixture. Plan called for 33KW He cooldown capability, 12 KW steady state, major challenges for JSC JSC currently has 7 KW He capability Plan required 10 trucks of LN2/day during cooldown Large Risk on Cooldown Time Assumptions Clean room Clean room Interferometers, Sources, Null Lens and Alignment Equipment Are in Upper and Lower Pressure Tight Enclosure Inside of Shrouds where Cryo Cycle Needed to Fix Problems

19. JSC “Cup Up” Test Configuration Center of Curvature Null and Interferometer Accessible from top Auto-Collimating Flats (isolators above connected to hard points on top of chamber). Telescope Cup Up Gravity offloaded and On Ambient Isolators Connected to Concrete) Focal Plane Interferometer and sources accessible from below • Isolators moved outside of shroud/vacuum • Telescope comes in deployed on tracks with minimal time in chamber before pump down

20. Contamination Plan • “Cup Up” test at JSC is not a major contaminant source • Launch effects are major driver • Ariane meeting planned for this fall • Particle generation by sunshield rubbing during launch? • We will be able to clean mirrors • Need independent review of all models, assumptions, methods • Detail required: cleaned mirrors have different particle size distributions and different BRDF shapes than before cleaning • Goal is twofold: • Cost-effective particulate contamination plan • Consistency with SAT assumptions regarding sensitivity losses

21. Summary • All review committees endorse JWST plans • Scientific descope recommended by SAT accepted and being implemented • Cost control and risk reduction approach endorsed by SAT and IPAO reviews • Replan in progress for new launch date and budget • Technology progress excellent, will be ready for NAR