Advanced Technologies For Future Space Telescopes And Instruments

Transcript

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 1 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 2 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) 4 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 6 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 7 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 9 XEUS: high resolution spectroscopy (SNRs, X-ray binaries, stellar coronae) Wolter I design for X-ray telescopes 10 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) 15 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 … 18