Download Advanced Technologies for Future Space Telescopes and Instruments

Advanced Technologies
for
Future Space Telescopes
and
Instruments
- A sample of upcoming astronomy missions
- Interferometry in space (Darwin)
- Very large telescopes in orbit (XEUS)
- Future space telescope concepts (TPF)
Dr. Ph. Gondoin (ESA)
IR and visible astronomy missions
(ESA Cosmic Vision – NASA Origin programs)
DARWIN
TPF
GAIA SIM
Herschel
SIRTF
Planck
Eddington Kepler
Corot
JWST
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GAIA Science Objective:
Understanding the structure and evolution of the Galaxy
Payload GAIA payload
• 2 astrometric telescopes:
• Separated by 106o
• SiC mirrors (1.4 m × 0.5 m)
• Large focal plane (TDI operating
CCDs)
• 1 additional telescope equipped
with:
• Medium-band photometer
• Radial-velocity spectrometer
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Technology requirements for GAIA
(applicable to many future space missions)
• Large focal plane assemblies:
– 250 CCDs per astrometry field, 3 side buttable, small pixel (9 µm),
high perf. CCDs ( large CTE, low-noise, wide size, high QE), TDI
operation
• Ultra-stable telescope structure and optical bench:
• Light weight mirror elements:
– SiC mirrors (highly aspherized for good off-axis performance)
Large SiC mirror for space telescopes (Boostec)
ESA Herschell telescope:
1.35 m prototype
3.5 m brazed flight model
(12 petals)
3
James Webb Space Telescope (JWST)
Mirror Actuators
Beryllium Mirrors
SBMD
AMSD
Mirror System
Wavefront Sensing and Control, Mirror Phasing
Secondary mirror uses six actuators
In a hexapod configuration
Primary mirror segments attached to backplane
using actuators in a three-point kinematic mount
NIRSpec: a Multi-object Spectrometer (MOS)
Specifications:
1-5 µm coverage, 3 x 3 arcmin FOV
R ~ 1000 and 100 on > 100 sources simult.
Micro-Shutter Array
Grating/Prism
Fore optics Collimator
Detector
Array
Camera
GSFC Micro-shutter (MEMS)
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Advanced Technologies
for
Future Space Telescopes and Instruments
• 1) Introduction
•
•
•
•
•
2) A sample of upcoming astronomy missions
3) Interferometry in space: Darwin
4) Very large telescopes in orbit: XEUS
5) Future space telescope concepts: TPF
6) Summary
The Darwin Space Interferometer
(ALCATEL 2000 study)
• 6 Telescope free-flyers
• 1 Beam combiner
• 1 Master spacecraft
5
DARWIN science objectives
1) Nulling interferometry
to detect and characterize Earth-like
planets around nearby star (i.e. how
unique is the Earth as a planet?)
to search for exo-life around nearby
stars (i.e how unique is life in the
universe?)
2) Imaging at high spatial resolution
e.g active galaxy nuclei
Principle of a (Bracewell) nulling interferometer
B
x
bright output
0
π
dark output
Æ
Fringe spacing › λ/B
Transmission › sin2(θ)
Transmission map
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The
IRSI-Darwin
configuration
Beam
Combination
(3)
Nulling (Generalized Angel’s Cross) + Internal modulation
A=4/9,Ф=л
A=1/9,Ф=0
Nulling rejection: >105
baseline accuracy: 1cm
OPD control: < 20 nm
amplitude matching: < 10-2
pointing accuracy < 20 mas
A=1,Ф=0
A=4/9,Ф=л
Darwin telescopes and beam-combiner
•
•
6 telescope free-flyers
– 1.5 m Korsch telescopes (+
transfer optics)
– Wide-field camera (attitude
sensing)
– Dual-field capability
(reference+target)
– Hub alignment device
1 beam combiner (Imaging or
nulling mode)
–
–
–
–
–
–
–
Metrology
Delay lines+fringe sensors
Amplitude+polarisation control
Achromatic phase shifting
Spatial filtering
Beam combination
Spectroscopy, detection
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Integrated optics beam combiner
Light injection
Photometric
output 1
Interferometric
output
Photometric
output 2
Y-junctions
Reversed
Y-junction
α
injection angle
Light injection
Darwin-GENIE: an ESA-ESO collaboration
Motivations:
•to experiment nulling interferometry on-ground
•to benefit from ESO VLTI experience
•to test key Darwin technology
Objectives:
1.
Nulling technology demonstrator
2.
Preparation of Darwin program
3.
Low-mass companions
4.
General user instrument
European
Southern
Observatory
8
Advanced Technologies
for
Future Space Telescopes and Instruments
• 1) Introduction
•
•
•
•
•
2) A sample of upcoming astronomy missions
3) Interferometry in space: Darwin
4) Very large telescopes in orbit: XEUS
5) Future space telescope concepts: TPF
6) Summary
XEUS: exploring the deep X-ray Universe
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XEUS: high resolution spectroscopy
(SNRs, X-ray binaries, stellar coronae)
Wolter I design for X-ray telescopes
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Operating X-ray Astronomy Satellites
XMM-Newton:
Chandra:
•Mirror area 0.4 m2
•Spatial resolution 15’’ HEW
•Limiting sensitivity: 10-15 erg cm-2 s-1
•Mirror area 0.08 m2
•Spatial resolution 0.5’’ HEW
•Limiting sensitivity: 10-16 erg cm-2 s-1
XEUS – Mission Concept
XEUS will provide a major leap forward in capability:
• Collecting area: 30 m2 at 1 keV, 3 m2 at 8 keV, 1000 cm2
at 20 keV
• Imaging resolution: 2” HEW (Half Energy Width) at
1keV
• Limiting sensitivity: 4 10-18 erg cm-2 s-1 (250 times deeper
than XMM-Newton)
• Spectral resolution goal: 1 eV at 1 keV
• Broadband spectral coverage: 0.05 to 30 keV
• Field of view: 5 arc minutes
11
X-ray Mirror Technology
XEUS Mirror Spacecraft Design
12
XEUS final telescope assembly
at the International Space Station
XEUS
a Mirror Spacecraft + an Instrument Spacecraft
(deployment in fellow traveler orbit)
13
XEUS Instruments
Imaging detectors with intrinsic spectral resolution
Large field-of-view
imaging spectrometer:
Semiconductor based
(e.g. DEPFET array)
High energy resolution
imaging spectrometers:
Cryogenic (STJ-based
and/or bolometer array)
70 x 70 mm2
0.1 - 30 keV
50 eV FWHM @ 1 keV
75 µm position resolution
70 µs timing resolution
QE > 90% for E > 280 eV
Top = 280 K
7 x 7 mm2
0.05 - 7 keV, 0.5 - 15 keV
3 eV (goal 1 eV) @ 1 keV
150 µm position resolution
1 µs timing resolution
10 kHz/pixel
20-90 mK, 15-30 mK
Advanced Technologies
for
Future Space Telescopes and Instruments
• 1) Introduction
•
•
•
•
•
2) A sample of upcoming astronomy missions
3) Interferometry in space: Darwin
4) Very large telescopes in orbit: XEUS
5) Future space telescope concepts: TPF
6) Summary
14
“Darwin-TPF” Precursor Missions
Technology Flow to the Future
SIM
SIRTF
IR Background source
Circumstellar environment
Interferometry
Precision Metrology
TPF - Darwin
Terrestrial Planet Detection &
Spectroscopy
KEPLER
Planet Detection
JWST
6.5 Meter Aperture
Segmented Optics
Cryogenic Components
COROT
Planet Detection
Eddington
Planet Detection
(ST-3) , SMART3?
Precision Formation Flying
Fringe Acquisition?
Planet Imager
Terrestrial Planet Imaging
TPF Concepts
Visible Coronograph
Primary Mirror Option
• 4 x 10 Meter Elliptical (Control actuators)
Deformable Mirror at image pupil plane
Classical coronograph/ shaped pupil mask
Deployable Secondary Optics
Deployable Stray-Light Baffle
Apodized Square Apertures (8 x 8 m)
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TPF Concepts
“Eyepiece” Spacecraft
Very large IR telescope:
•Eyepiece spacecraft
• assembly housing,
• secondary optics
• focal plane
• baffle for sunlight rejection
and optics cooling
~500 meters
Sun Acceptance
Angles
• Metrology spacecraft
Metrology Spacecraft
Primary with Subapertures
• Primary is a
• lightweight monolithic truss
supporting sub-apertures
•actuators position of
individual mirror elements
TPF Concepts
Space Truss Structures:
Structurally connected IR interferometer
Two interlaced Bracewell
• 4 x 3.5 telescopes
• 40 m truss structures
“Simpler” to built and operate than a free-flyer
Difficult to deploy
16
TPF Concepts
Hypertelescopes with densified pupil imaging (2-d connected or free flyers)
Advanced Technologies
for
Future Space Telescopes and Instruments
• 1) Introduction
•
•
•
•
•
2) A sample of upcoming astronomy missions
3) Interferometry in space: Darwin
4) Very large telescopes in orbit: XEUS
5) Exo-planets: technology flow for the future
6) Summary
17
Advanced Technologies for
Future Space Telescopes and Instruments
• Large lightweight mirrors
–
–
segmented, deployable and active mirror technology (JWST)
very large telescopes assembled in space (XEUS)
• Large focal plane arrays
– Buttable visible and IR detector technology (Gaia, Eddington, JWST)
– New X-ray detectors with intrinsic spectral resolution (e.g. STJ/XEUS)
• New optical components, materials and manufacturing processes:
– IR monomode optical fibers, integrated optics for interferometry (Darwin)
– Micro-shutter (MEMS) for MOS spectrometer (NIRSpec/JWST)
– Thin lightweight mirror segments Be, SiC, replicated optics, actuators
• Spacecraft engineering
–
–
–
–
–
Propulsion (e.g FEEPs)
Thermal control (e.g deployable sunshields, cryocoolers)
Space truss structures, deployment mechanisms
Metrology, formation flying
…
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