New Technologies for Exoplanet Detection with Mid-IR Interferometry Peter R. Lawson Oliver Lay, Stefan Martin, Robert Peters, Andrew Booth, Robert Gappinger, Alexander Ksendzov, and Daniel Scharf Jet Propulsion Laboratory California Institute of Technology New Technologies for Probing the Diversity of Brown Dwarfs and Exoplanets Shanghai, China Thursday, 23 July 2009

Overview Spectra of Earth-like exoplanets Architecture & Design Team Studies Technology Demonstrations Future Prospects Summary and Conclusion Terrestrial Planet Finder May 1999 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

McKee–Taylor Report: Decadal Survey 2000 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Frank Selsis (Lyon) 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Architecture Trades and Design Team Studies 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

TPF-Darwin Architecture Studies Linear DCB TPF-I Darwin Bow-Tie X-Array Planar TTN Emma TTN Emma X-Array TPF-Darwin Stretched X-Array 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Properties of a TPF-I Observatory Illustrative Properties of a TPF-I Observatory Concept Parameter 4-Telescope Chopped X-Array Emma Design Collectors Four 2-m diameter spherical mirrors, diffraction limited at 2 μm operating at 50 K Array shape 6:1 rectangular array Array size 400 × 67 m to 120 × 20 m Wavelength range 6–20 µm Inner working angle 13–43 mas (at 10 mm, scaling with array size) Angular resolution 2.4 mas to 8.2 mas (at 10 μm, scaling with array size) Field-of-view 1 arcsec at 10 µm Null depth 10-5 at 10 mm (not including stellar size leakage) Spectral resolution Δλ/λ 25 (for planets); 100 for general astrophysics Sensitivity 0.3 µJy at 12 µm in 14 hours (5s) Target Stars 153 (F, G, K, and M main-sequence stars) Detectable Earths 130 (2 year mission time, 1 Earth per star) Exozodiacal emission Less than 10 times our solar system Biomarkers CO2, O3 , H2O, CH4 Field of regard Instantaneous 45° to 85° from anti-Sun direction, 99.6% of full sky over one year. Orbit L2 Halo orbit Mission duration 5 years baseline with a goal of 10 years Launch vehicle Ariane 5 ECA or equivalent 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Mass estimates and launch packaging 3 m design = 6900 kg (w 30% reserve) Mass saving of 30% over previous design Compatible with medium lift LV Delta IV M+ Ariane 5 ECA Scaling to smaller diameters 3.0 m 6900 kg 2.0 m 4800 kg 1.5 m 4100 kg 1.0 m 3700 kg Inspired by a design by Thales Alenia Space 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Technology Demonstrations 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Technology for a Mid-IR Interferometer Starlight suppression Null depth & bandwidth Null stability Formation flying Formation control Formation sensing Propulsion systems Cryogenic systems Active components Cryogenic structures Passive cooling Cryocoolers Integrated Modeling Model validation and testbeds Science Requirements Architecture trade studies 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Technology for Starlight and Noise Suppression Spatial Filtering Adaptive Nulling Array Rotation, Chopping, and Averaging Spectral Filtering

Single-Mode Mid-Infrared Fibers Chalcogenide Fibers (NRL) A. Ksendzov et al., “Characterization of mid-infrared single mode fibers as modal filters,” Applied Optics 46, 7957-7962 (2007) Transmission losses 8 dB/m Suppression of 1000 for higher order modes Useable to ~11 microns Silver-Halide Fibers (Tel Aviv Univ) A. Ksendzov et al. “Modal filtering for mid-infrared nulling interferometry using silver halide fibers,” Applied Optics 47, 5728-5735 (2008). Transmission losses 12 dB/m Suppression of 16000 possible with a 10-20 cm fibre, with aperturing the output. Useable to ~18 microns (?) Example Chalcogenide Fibers, produced on contract by the Naval Research Laboratory http://planetquest.jpl.nasa.gov/TPF-I/spatialFilters.cfm 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Broadband Intensity and Phase Compensation Birefringent element splits polarizations Pupil Stop Parabolic mirror ~ 10 x 14 cm Dispersive element splits wavelengths Uncompensated beam in (~4 cm) S-polarization Deformable mirror P-polarization Compensated beam out (~4 cm) Pupil Stop Dispersive element re-combines wavelengths Birefringent element re-combines polarizations 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

TPF-I Milestone #1 and #3: Adaptive Nuller TPF-I Milestone #1 completed, July 2007 Demonstrated 0.09% intensity compensation and 4.4 nm phase compensation TPF-I Milestone #3 completed, February 2009 Demonstrated 1.0×10-5 mean null depth with a 34% bandwidth in three 6-hour experiments. “Broadband phase and intensity compensation with a deformable mirror for an interferometric nuller,” R. D. Peters, O. P. Lay and M. Jeganathan, Applied Optics 47, 3920-3926 (2008). 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

100,000:1 with 34% Bandwidth,  = 10 m 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Chop, Rotate, Average, Spectral Fit 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Demonstrate array rotation, chopping, and averaging Detect planet signal at a contrast of ≤ 10-6 relative to the star Show residual starlight suppression from phase chopping and rotation ≥ 100. Tests run for a total duration of 10,000 s, with one or more rotations at timescales of ≥ 2000 s. 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Planet Detection Testbed 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Technology for Formation Flying Guidance, Navigation & Control

Precision Formation Flying 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Precision Leader-Follower Maneuver 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

TPF-I Milestone #2: Formation Control Testbed TPF-I Milestone #2 experiments for the formation precision performance maneuver were completed 30 September 2007 Goal: Per axis translation control < 5 cm rms Per axis rotation control < 6.7 arcmin rms Demonstrated with arcs having 20 and 40 degree chords. Experiments repeated three times, spaced at least two days apart. Milestone Report published 16 January 2008 x axis 4.77 arcmin rms y axis 5.14 arcmin rms z axis 2.70 arcmin rms x axis 2.66 arcmin rms y axis 2.93 arcmin rms z axis 1.67 arcmin rms Relative path of robots for an arc with 20 degree chords x axis 1.39 cm rms y axis 2.41 cm rms Example Milestone Data: Rotation maneuver with 20 degree chord segments 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Recent Advances in Formation Flying Orbital Express (DARPA) May-July 2007 Demonstrated in-orbit servicing of satellites Relative maneuvers of two satellites Transfer of liquids and batteries Autonomous Transfer Vehicle (ESA) April 2008 Unmanned transport to the International Space Station 10.3-m long and 4.5-m diameter GPS, video, and human supervision Two days of demos, and rendezvous and docking 30 September 2008, completed a destructive re-entry 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Prisma (2009) and Proba-3 (2012) Prisma (Swedish Space Corporation) launch 24 November 2009 Rendezvous and docking demonstrations Prototype “Darwin” RF metrology Proba-3 (ESA) 2012 30-150 m separation for demonstrations Millimeter-level range control RF Metrology & Optical metrology AO for the provision of the coronagraph now out http://sci.esa.int/proba_3_AO Prisma Proba-3 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Related New Technologies 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Large Light-Weight Optics Herschel Primary Mirror 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Cryocoolers Advanced Cryocooler Technology Development Program JWST Cryocooler (NGST) 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Technology Development in Europe Infrared Nulling testbeds (ESA) Thales Alenia Space EADS Astrium University of Delft Institut d’Astrophysique Spatiale Cryogenic Delay Line (ESA) TNO, The Netherlands Integrated Optics and Fiber Optics (ESA) LAOG, Université Joseph Fourier, Grenoble EADS Astrium / TNO Université de Rennes Université de Montpellier Breadboard demonstrator for PEGASE (CNES) Cryogenic mid-IR testbed, Inst. Astrophysique Spatiale (under design) RF Metrology for formation flying (Thales Alenia Space) Thales Alenia Space TNO Inst. Astrophysique Spatiale 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Interferometer Technology Metrics Specs Performance to date Performance target prior to Phase A Flight (preliminary) Nulling Average null depth 9.9x10-6 (34%BW) Milestone #3 1.0x10-5 Intensity control 0.09% Milestone #1 0.2% 0.13% Phase control 4.4 nm 5.0 nm 1.5 nm Stability timescale 21,600 s 5,000 s > 50,000 s Bandwidth 8.4-11.6 µm (34%) 8.3 to 10.7 µm (25%) 7 to 17 µm Formation Flying Number of S/C 2 Robots 3 Robots 5 S/C Relative control 1.4 - 4.6 cm range, 1σ (formation rotation) Milestone #2 5 cm range, 1σ 2 cm range 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Accomplished Remaining 1999–2009 2010–2020 Room-temperature experiments & ground-based Broadband mid-infrared starlight suppression has been demonstrated at flight performance levels using the adaptive nuller System-level planet detection has been demonstrated using the Planet Detection Testbed Formation Flying algorithms demonstrated with traceability to flight. Related cryogenic technology Herschel mirror development Cryocooler work for JWST Cryogenic delay line development for ESA Cryogenic engineering & space-based testing Demonstrate component, subsystem, and system performance in a cryogenic environment Demonstrate the detection of biosignatures Validate models of the observatory Complete integration and test plans Demonstrate space-based interferometry Demonstrate space-based formation flying 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers 31

Further Reading http://planetquest.jpl.nasa.gov/TPF-I/ R. D. Peters, O. P. Lay, and M. Jeganathan, “Broadband phase and intensity compensation with a deformable mirror for an interferometric nuller,” Applied Optics 47, 3920–3926 (2008) A. Ksendzov, et al., “Modal filtering for mid-infrared nulling interferometry using single-mode silver halide fibers,” Applied Optics 47, 5728–5735 (2008) A. Ksendzov, et al., “Characterization of mid-infrared single mode fibers as modal filters,” Applied Optics 46, 7957–7962 (2007) R. O. Gappinger, et al. “Experimental evaluation of achromatic phase shifters for mid-infrared starlight suppression,” Applied Optics 48, 868–880 (2009) http://planetquest.jpl.nasa.gov/TPF-I/ This work was conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers 32

Backup Slides 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

Terrestrial Planet Finder Interferometer Salient Features Formation Flying Mid-IR nulling Interferometer Starlight suppression to 10-5 Heavy launch vehicle L2 baseline orbit 5 year mission life (10 year goal) Potential collaboration with European Space Agency Science Goals Detect as many as possible Earth-like planets in the “habitable zone” of nearby stars via their thermal emission Characterize physical properties of detected Earth-like planets (size, orbital parameters, presence of atmosphere) and make low resolution spectral observations looking for evidence of a habitable planet and bio-markers such as O2, CO2, CH4 and H2O Detect and characterize the components of nearby planetary systems including disks, terrestrial planets, giant planets and multiple planet systems Perform general astrophysics investigations as capability and time permit 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers 17

State of the Art in Nulling Interferometry 24 July 2009 - Shanghai, China P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers