Photo of Wes Traub
By Peter Lawson

We are excited to announce that six new proposals for Technology Development for Exoplanet Missions (TDEM) have been selected. These proposals include various topics in coronagraph and starshade technology. Two proposals were selected for starlight suppression demonstrations using coronagraph techniques that yield very small inner working angles. The first, awarded to Olivier Guyon of the University of Arizona, is entitled “Advances in Pupil Remapping (PIAA) coronagraphy: improving Bandwidth, Throughput and Inner Working Angle.” This work will use pairs of specially shaped mirrors to reshape the diffraction features that lie close-in to a stellar image, thus making planet detection easier for close-in planets. This is an extension of previously successful laboratory work. The second is awarded to Eugene Serabyn of the Jet Propulsion Laboratory, Caltech, for “Demonstrations of Deep Starlight Rejection with a Vortex Coronagraph.” This approach uses a rotationally symmetric phase mask that operates through the polarization properties of liquid crystal polymers. Prior work in this area has included preliminary lab demonstrations and observations of HR 8799 with the Palomar 5-m telescope.

A proposal by Stuart Shaklan of JPL/Caltech was selected to complete the third in the original series of TPF Coronagraph Milestones: “Coronagraph Starlight Suppression Model Validation: Coronagraph Milestone #3A.” This effort will demonstrate, using a band-limited Lyot mask, the agreement between models and laboratory experiments at contrasts greater than 10-9 for multiple sources of misalignment errors.

Two proposals were selected for starlight suppression demonstrations using Visible Nulling Coronagraph (VNC) technology. This approach, using segmented deformable mirrors and a compact array of single-mode optical fibers, is well-suited for operations with future space-based segmented-mirror telescopes. Richard Lyon of NASA’s Goddard Space Flight Center will be funded for “Compact Achromatic Visible Nulling Coronagraph Technology Maturation,” to design and build a VNC engineering test unit and demonstrate contrasts of 10-9. Jagmit Sandhu of JPL/Caltech will be funded for “Visible Nulling Coronagraph (VNC) Technology Demonstration Program” to demonstrate speckle subtraction at levels exceeding 10-10 using an interferometric calibration system.

Continued efforts in the development of starshade technology will be funded through an award to Jeremy Kasdin of Princeton University for “Verifying Deployment Tolerances of an External Occulter for Starlight Suppression.” Prior TDEM work focused on achieving the design tolerances of a single starshade petal. This effort will demonstrate a repeated stow and deploy of a starshade petal to within the deployment tolerances, as well as characterizing the thermal properties of a deployed petal.

These awards are grants and are contingent on availability of funds. TDEM is one of three subtopics of the Strategic Astrophysics Technology solicitation within NASA’s Research Opportunities in Space and Earth Sciences (ROSES).

In other ExEP technology news, laboratory tests this past year have achieved new records. Contrasts of 2 x 10-10 in 2% and 2 x 10-9 in 20%, over a dark hole of 3–15 λ/D were reached using a Band-Limited Hybrid Lyot Coronagraph, exceeding the performance attained through TPF-C Milestones. An order-of-magnitude improvement in performance was shown in 2010-2011 with the Vector Vortex and Phase-Induced Amplitude Apodization (PIAA) techniques, and excellent progress made in implementations of Visible Nulling Coronagraphs. A new starshade petal is now under construction to demonstrate the flight tolerances for manufacturing a starshade, and work is also progressing well in coronagraph modeling, speckle sensing methods, and detector development.

The Exoplanet Program is looking forward to the 219th Meeting of the American Astronomical Society in Austin, Texas, where we are planning to host an evening session devoted to New Worlds Technology that emphasizes technology for small missions, 6:30–8:00 pm, Tuesday 10 January 2012. In addition we will be coordinating a poster session describing recent advances in technology development.