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TitleJames Webb Space Telescope: Why are we building it like this?
LanguageEnglish
File Size7.9 MB
Total Pages101
Table of Contents
                            James Webb Space Telescope: Why are we building it like this?
James Webb Space Telescope
Science Requirements Sources
Endorsements matter!
Choice of International Responsibilities
Slide Number 6
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Slide Number 8
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Slide Number 11
Slide Number 12
Slide Number 13
Slide Number 14
Slide Number 15
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Slide Number 20
Why Infrared?
Why so big?
JWST and its Precursors
Sun-Earth L2 orbit required
Slide Number 25
No user-serviceable parts inside
HOW JWST WORKS
JWST Design: Key Features
JWST’s Telescope Design
Beryllium Mirrors only choice
Slide Number 31
Aft-Optical System Optics Complete
Huge Shrinkage Challenges
Primary Mirror Backplane
Choice of Instruments & Detectors
JWST Instrumentation
NIRCam will provide the deepest near-infrared images ever and will identify primeval galaxy targets for the NIRSpec
Choice of Near IR Spectrometer
The NIRSpec will acquire spectra of up to 100 galaxies in a single exposure
FLIGHT NIRSpec
Aperture control: 250,000 programmable micro-shuttersSystem at TRL-8 and delivered to ESA June 2010
Flight MIRI has been delivered
FGS/NIRISS have been delivered, provide pointing control & imaging spectroscopy
Flight Fine Guidance Sensor
Choice of MIRI Cooler
Choice of Fine Pointing Control
Choice of Propulsion
Choice of Sunshield Design
Rigid Body Pointing
Robotic Assembly
RF communications good enough
Focusing Algorithms
Testbed Telescope
Predicted Image Quality
Ground Based Testing
Optical Telescope Element will be integrated on this alignment stand using the machine at right for primary mirror segment installationfollowed by attachment of the ISIM to make OTIS – scheduled for 2016
Off to JSC to a giant National Historic Landmark vacuum chamber from the Apollo era
Including the installation of the GHe shrouds and refrigeration system for taking JWST to its flight operating temperature
Slide Number 59
I wish…
I wish…
40K is cold enough for telescope
Sunshield Deployment
3D Shape Measurement: Layer 3
Slide Number 65
JWST Deployment
Want to Learn More about JWST?
The End
Primary Mirror Backplane
Optical Telescope Element will be integrated on this alignment stand using the machine at right for primary mirror segment installationfollowed by attachment of the ISIM to make OTIS – scheduled for 2016
Slide Number 71
The MIRI instrument will detect key discriminators that distinguish the earliest state of galaxy evolution from more evolved objects
The FGS-Guider and NIRSS provide imagery for telescope pointing control & spectroscopy for Ly-a galaxy surveys and extra-solar planet transits
Mirror Reflectivity
Flight Mirrors: Cryo-Performance
Sky Background
Observatory Schedule
JWST Schedule
ISIM is the science instrument payload of the JWST
Slide Number 80
NIRSpec delivery expected during 2012
FGS is on schedule for delivery during 2012
ETU SI integration with ISIM structure proceeding well
Integration and Test of the James Webb Space Telescope
ISIM I&T has already begun; SI integration will be a highlight, starting with 1st delivery in the spring of 2012.
Key Aspects of the ISIM Cryo-Vac Program
Key Aspects of the JSC OTIS Cryo-Vac Program
Slide Number 88
Sunshield and Rest of Spacecraft Progress On Their Own I&T Path
I&T Flow Overview and Responsibilities
Key Design Drivers
Slide Number 92
Telescope Mirrors Gold Coated
Flight Mirrors: Cryo-Performance
Slide Number 95
Slide Number 96
NIRCam Environmental Testing to Begin
Test Unit SI integration with ISIM structure worked well
Slide Number 99
OSIM certified for cryo-vac in 2012
Ambient Optical Alignment Stand for OTE & OTIS assembly recently installed in the SSDIF clean room
                        
Document Text Contents
Page 1




John Mather
JWST Senior Project Scientist
NASA™s Goddard Space Flight Center
on behalf of 7
billion current Earthlings
, ~10,000 future observers, ~ 1000
engineers and technicians, ~ 100 scientists worldwide, 3 space agencies
James Webb Space Telescope:
Why are we building it like this?



Page 2




JWST
James Webb Space Telescope
Organization
Mission Lead
:
Goddard Space Flight Center
Senior Project Scientist:
Dr John Mather
International collaboration
: ESA & CSA
Prime Contractor
:
Northrop Grumman Aerospace
Systems
Instruments
: Ł Near Infrared Camera (
NIRCam
) ΠUniv. of
Arizona
Ł Near Infrared Spectrograph (
NIRSpec
) Œ ESA Ł Mid
-Infrared Instrument (MIRI)
ΠJPL/ESA
Ł Fine Guidance Sensor (FGS) & Near IR Imaging
Slitless Spectrometer
ΠCSA
ŁOperations
:
Space Telescope Science Institute
Description
ŁDeployable infrared telescope with 6.5 meter diameter segmented adjustable primary mirror
ŁCryogenic temperature telescope and instruments for infrared performance
ŁLaunch on an ESA
-supplied Ariane 5 rocket to Sun
-Earth L2
Ł5-year science mission requirement (10
-year propellant lifetime)



Page 50




JWST
Robotic Assembly
ŁConsidered robotic assembly concepts
ŁNot needed for this size telescope: hinges,
cables, actuators, and motors are good

enough (= robots with zero IQ)
ŁWould be valuable if volume were the

limiting resource instead of mass
ŁMaybe
next time
! (or, maybe we can get a
bigger rocket?)



Page 51




JWST
RF communications good enough
ŁData rate not very high: comparable to HST
ŁRange ~ 50x greater (HST goes via
TDRSS) but still OK via Deep Space

Network (larger dishes)
ŁConsidered optical comm,
but would have
had to develop it ourselves
Πnow more
mature
Πand provide at least 2 ground
stations in new locations (e.g. desert in

Chile)



Page 100




16 Dec 2011
100
Presentation to: GSFC Code 600 staff
OSIM integration complete
Space System Development & Integration Facility (SSDIF)
Largest laminar flow clean room in the world (Class 10,000
OSIM certified for cryo
-vac in 2012



Page 101




16 Dec 2011
101
Presentation to: GSFC Code 600 staff
Ambient Optical Alignment Stand for OTE & OTIS
assembly recently installed in the SSDIF clean room

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