Transcript JWST - IISME Community Site

The Space Telescope and The Lagrangian Point
James Webb Space Telescope (JWST)
 Launch Scheduled for 2018 by European Space Agency
 18 Segment Primary Mirror (Gold-plated Beryllium; 25m2)
 L-2 Orbit Enables Passive Cooling to 45 Kelvin
 Operational Life >10 years; Mass ~ 6000 kg
 Four Instruments:
– Near-Infrared Camera
– Near-IR Spectrometer
– Fine Guidance Sensor
– Mid-Infrared Instrument
-378 oF
6.7 tons !
Full-Scale Model at Goddard Space Flight Center
3
Largest Cryogenic Telescope Ever Built
Seven Times the Light-Gathering Capability of the Hubble Space Telescope
Wavelength
Spectrum
Coverage
from
Optical
to Infrared
Similar
Angular
Resolution
Hugh
Variety of
Analysis
Available
to Users
JWST, 1000s per band
(simulated)
Fun Facts – Detector/Sensing Capability
• If the JWST observatory were sitting on the surface of the earth looking at the
moon and a night light* were turn on or a candle+ were lit on the dark side of the
moon the observatory would detect it**!
Assumes: 5W gray-body emitter w/o atmosphere
JWST Architecture
Telescope mirrors are fabricated from Beryllium
Key physical properties of beryllium (Be):
• low coefficient of thermal expansion at 50 K
• high thermal conductivity
• high stiffness to mass ratio
• Type O-30 spherical powder
• uniform CTE, high packing density, low oxide content
Primary mirror mass properties
• substrate: 21.8 kg
• segment assembly: 39.4 kg
• OTE area density: ~28 kg m-2
• HST (ULE) ~ 180 kg m-2
• Keck (Zerodur) ~ 2000 kg m-2
Mirror Manufacturing
Before
After
Finished
Mirror
Segment
Be Billet
250 kgs
21 kgs
Beryllium Dust
is Recycled
Over 90% of material is removed to make each mirror segment!
(Want a little Mirror with your Beryllium dust?)
8
End
section
of a
typical
human
hair
Mirror
Surface
Tolerance
Allowable PMSA Surface Error
Surface of a Primary Mirror Section Assembly (PMSA)
9
Cryo Cycle 5 at MSFC XRCF with Gold-Coated EDU
10
Cryogenic Optical Testing & Metrology
Preparations of the
Primary Mirror Section at
Marshal Space Flight Center’s
X-Ray & Cryogenic Facility
Integrated Science Instrument Module (ISIM)
ISIM is composed of:
• JWST Data Acquisition & Analysis Instruments
• Structure, Thermal, Comm. & Control Systems
Region 1:
Science Instrument Optics Assemblies
Near Infrared Camera (NIRCam)
Near Infrared Spectrograph (NIRSpec)
Mid Infrared Instrument (MIRI)
Fine Guidance Sensor w/Tunable Filter (FGS/TF)
Optical Bench Structure
Radiators and support structure
Region 2:
Electronics Compartment
Focal Plane Electronics (FPE)
Instrument Control Electronics (ICE, MCE)
ISIM Remote Services Unit (IRSU)
Region 3
Command & Data Handling (C&DH) Electronics
JWST Science Instruments
Ariane 5 Launch Configuration
Side View of
Stowed JWST
(no Sunshield)
Payload
Fairing
51.4 m
(170 ft)
Top View
Stowed JWST
ESC-A
Upper
Stage
H155
Core
Stage
P230
Solid
Booster
Vulcan Engine
5m
(16 ft)
Integration &Test Flow Overview
ISIM I&T
I&T Responsibility
OTE/ISIM
I&T
Execution Facility
NASA
GSFC SSDIF
OTE
Structure
I&T
NGAS M8
Observatory
EM Test Bed
(EMTB)
GSFC SSDIF, JSC 32
GSFC SSDIF
Pathfinder
Optics
Integration
GSFC SSDIF
Pathfinder
Cryo
Optics Test
JSC 32
Propulsion
Module I&T
NGAS M3
Spacecraft
Panel I&T
NGAS M8
Sunshield
Pathfinders
(EPF/IVA)
NGAS M8
N/A
Sunshield
I&T
NGAS M8
Spacecraft
Element I&T
NGAS M8, M4 TV
Complete
Observatory
I&T
NGAS M8, LATF, M4 Vibe
Launch
Site
I&T
LV
Integ
CSG S5, BAF, ZL3
Launch
NGAS R8
Cryo
Optics
Test
OTE
I&T
NGST M8
OTE
Pathfinder
Structure
NGAS
ITT
ESA /
Arianespace
ISIM will be tested in the GSFC SES chamber using
an Optical Telescope Element Simulator (OSIM)
SES
chamber
GHe shroud instillation and
test completed July 09
LN2 Shroud
He shroud
ISIM
OSIM
Fold Mirror 3 Tip/Tilt
Gimbal Assembly
Alignment Diagnostic Module
OSIM Primary Mirror
Vibration
Isolation
Supports
1/3 Scale Sunshield Test Complete - December 2009
Sunshield IVA Deployment Testing
Kapton Spring Under Load
Stowed Sunshield IVA with the OTE Simulator
Flight Instrument Status
F187N – B
Fully integrated and aligned NIRSpec
FGS undergoing integration
Fully integrated MIRI
NIRCam Flight hardware status