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At least 19 records

Starlight Nulling Technology at the Jet Propulsion Laboratory

The current interests in extra-solar planet detection and space-based and ground-based interferometry for astronomical observations has led to the development of a number of nulling instrument designs at the Jet Propulsion Laboratory (JPL) and elsewhere. This paper summarizes briefly JPL's efforts in nulling interferometry to date and consists of illustrations of some key nulling activities. Basic layouts of nulling testbeds are described and key applications discussed.

Terrestrial Planet Finder

Pupil configurations for an interferometric TPF mission

The primary goal of the proposed Terrestrial Planet Finder mission is the direct detection of radiation from potential terrestrial planets orbiting around nearby stars. However, the faintness of the expected signals leads to very stringent technical requirements on the optical performance. As a result, both of the candidate approaches currently under active development by the TPF project, infrared nulling interferometry with separated aperture telescopes, and optical coronagraphy with a large singl aperture telescope, require complex optical systems which push the state of the art.

TPF interferometry Terrestrial Planet Finder

A Dual 3-Element Nulling Interferometer for TPF

We present an interferometer that provides a null at the star and a direct measurement of both visibility amplitude and phase of the planets.

Nulling Interferometry Terrestrial Planet Finder

TPF Planet Detection Testbed: demonstrating deep, stable nulling and planet detection

The design of a testbed being built at the Jet Propulsion Laboratory is described. Simulatiung a dual chopped Bracewell interferometer, the testbed comprises a four beam star and planet source and nulling beam combiner. Since achieving a stable null is of great concern the testbed has many control systems designed to achieve stability of alignment and optical path difference over long periods of time. Comparisons between the testbed and the flight system are drawn and key performance parameters are discussed. The interaction between designs for phaseplate systems that achromatically invert the electric field of one of each pair of the incoming beams to achieve the null and the choice of fringe tracking schemes is also discussed.

interferometry

A visible light terrestrial planet finder - planet detection and spectroscopy by nulling interferometry with a single aperture telescope

Planet detection around a bright star depends the resolution of the imaging system and the degree of light suppression of the star relative to the planet. We present a concept for a visible light Terrestrial Planet Finding (VTPF) mission. Its major feature is an imaging system for planet detection using a nulling interferometer behind a single aperture telescope. This configuration is capable of detecting earth-like planets with a 5m aperture using both imaging and spectroscopic imaging modes. We will describe the principles of the system, and show results of studies demonstrating its feasibility.

planet

Interferometry science center

The Interferometry Science Center (ISC) is operated jointly by Caltech and JPL and is part of NASA's Navigator Program. The ISC has been created to facilitate the timely and successful execution of scientific investigations within the Navigator program, particularly those that rely on observations from NASA's interferometer projects. Currently, ISC is expected to provide full life cycle support for the Keck Interferometer, the Starlight mission, the Space Interferometry Mission, and the Terrestrial Planet Finder Mission. The nature and goals of ISc will be described.

optical interferometry community support

Mid-infrared nuller for Terrestrial Planet Finder: design progress and results

Nulling interferometry shows promise as a technique enabling investigation of faint objects such as planets and exo-zodiacal dust around nearby stars. At Jet Propulsion Laboratory, a nulling beam combiner based on a design built for the Keck Observatory in Hawaii has been used to pursue deep and stable narrowband nulls. We describe the design and layout of the Modified Mach Zehnder TPF nuller, and the results achieved in the laboratory to date. We report the stabilized 900,000 nulls achieved using a CO2 laser, and discuss the performance limitations and way forward to the deep, broadband nulls required for a space-borne nulling interferometer mission. We show briefly the results from Keck breadboard experiments: broadband transient nulls centered around 10.6 micron have been achieved ranging between 17500 at 18% bandwidth and 7500:1 at 29% bandwidth.

Serabyn, E.

Formations Near the Libration Points: Design Strategies Using Natural and Non-Natural Arcs

Space based observatory and interferometry missions, such as Terrestrial Planet Finder (TPF), Stellar Imager, and MAXIM, have sparked great interest in multi-spacecraft formation flight in the vicinity of the Sun-Earth/Moon (SEM) libration points. The initial phase of this research considered the formation keeping problem from the perspective of continuous control as applied to non-natural formations. In the present study, closer inspection of the flow, corresponding to the stable and center manifolds near the reference orbit, reveals some interesting natural relative motions as well as some discrete control strategies for deployment. A hybrid control strategy is also employed that combines both the natural formation dynamics with non-natural motions via input feedback linearization techniques.

Howell, K. C.