1. 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

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

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

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

5. 24 July Shanghai, China
P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

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

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

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

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

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

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

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

13. 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, (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, (2008).
Transmission losses 12 dB/m
Suppression of possible with a cm fibre, with aperturing the output.
Useable to ~18 microns (?)
Example Chalcogenide Fibers, produced on contract by the Naval Research Laboratory
24 July Shanghai, China
P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

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

15. 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, (2008).
24 July Shanghai, China
P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

16. 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

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

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

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

20. Technology for Formation Flying
Guidance, Navigation & Control

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

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

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

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

25. 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
m separation for demonstrations
Millimeter-level range control
RF Metrology & Optical metrology
AO for the provision of the coronagraph now out
Prisma
Proba-3
24 July Shanghai, China
P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

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

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

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

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

30. 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 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
cm range, 1σ
(formation rotation)
Milestone #2
5 cm range, 1σ
2 cm range
24 July Shanghai, China
P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers

31. 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 Shanghai, China
P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers 31

32. 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)
This work was conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
24 July Shanghai, China
P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers 32

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

34. 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 Shanghai, China
P. R. Lawson, New Technologies for Exoplanet Detection with mid-IR Interferometers 17

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