Stabilising a nulling interferometer using optical path difference dithering

Context. Nulling interferometry has been suggested as the underlying principle for the Darwin and TPF-I exoplanet research missions. Aims. There are constraints both on the mean value of the nulling ratio, and on its stability. Instrument instability noise is most detrimental to the stability of the nulling performance. Methods. We applied a modified version of the classical dithering technique to the optical path difference in the scientific beam. Results. Using only this method, we repeatedly stabilised the dark fringe for several hours. This method alone sufficed to remove the 1/ f component of the noise in our setup for periods of 10 minutes, typically. These results indicate that performance stability may be maintained throughout the long-duration data acquisitions typical of exoplanet spectroscopy. Conclusions. We suggest that further study of possible stabilisation strategies should be an integral part of Darwin/TPF-I research and developmen

Tests of achromatic phase shifters performed on the SYNAPSE test bench: a progress report

The achromatic phase shifter (APS) is a component of the Bracewell nulling interferometer studied in preparation for future space missions (viz. Darwin/TPF-I) focusing on spectroscopic study of Earth-like exo-planets. Several possible designs of such an optical subsystem exist. Four approaches were selected for further study. Thales Alenia Space developed a dielectric prism APS. A focus crossing APS prototype was developed by the OCA, Nice, France. A field reversal APS prototype was prepared by the MPIA in Heidelberg, Germany. Centre Spatial de Li\`ege develops a concept based on Fresnel's rhombs. This paper presents a progress report on the current work aiming at evaluating these prototypes on the SYNAPSE test bench at the Institut d'Astrophysique Spatiale in Orsay, France

The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description

On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2-7 m, while providing data at sub-mm to mm scales. We report on SuperCam's science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.In France was provided by the Centre National d'Etudes Spatiales (CNES). Human resources were provided in part by the Centre National de la Recherche Scientifique (CNRS) and universities. Funding was provided in the US by NASA's Mars Exploration Program. Some funding of data analyses at Los Alamos National Laboratory (LANL) was provided by laboratory-directed research and development funds

Interférométrie annulante pour l'exoplanétologie - Étude et développement du recombineur du banc PERSEE

For the past 15 years, the field of exoplanets detection has considerably expanded. Detection methods, first indirect, have allowed to discover no less than 420 new "worlds", sometimes astonishing. Scientists want now to characterize these exoplanets (particularly telluric ones) and Nulling interferometry is one of the direct detection methods assessed to do this. Within this framework, several space based projects are developed. Due to the complexity of these missions, it is necessary to test, first in laboratory, some technological aspects, as the principle of nulling interferometry. In 2006, CNES has decided to conduct an R&D on the payload of a two-telescope space based interferometer (typically the PEGASE instrument). Thus, the PERSEE test bench (Pegase Experiment for Research and Stabilization of Extreme Extinction) was conceived. The idea of PERSEE is to couple a nulling interferometer with a free flying simulator allowing introducing realistic disturbances and correcting them with active internal loops controlling the optical path difference and the pointing. This PhD work presents the design, the study and the development of one of the sub-systems of the bench : the beam combiner. This module is a new version of the "Modified Mach-Zehnder" beam combiner proposed by Serabyn et al. (2001). It has the particularity to combine the nuller and the Fringe Tracker system in order to minimize differential paths.Depuis maintenant 15 ans, le domaine de la détection d'exoplanètes s'est largement développé. L'utilisation de méthodes de détection, indirectes d'abord, a permis de découvrir pas moins de 420 nouveaux "mondes", parfois surprenants. Forts de cela, les scientifiques cherchent maintenant à caractériser ces exoplanètes. Ainsi des projets spatiaux, se basant sur la méthode de l'interférométrie annulante, ont pour but de réaliser des spectres de planètes géantes et telluriques. Compte tenu de la complexité de ces missions, la nécessité de tester, d'abord en laboratoire, certains aspects technologiques comme le principe de l'interférométrie annulante, est rapidement apparue. En 2006, le CNES a décidé de mener une étude R&D de la charge utile d'un interféromètre annulant a deux télescopes (typiquement l'instrument PEGASE). Ainsi, le banc de test PERSEE (Pegase Experiment for Research and Stabilization of Extreme Extinction) est né. Ce banc est le premier banc de test couplant un interféromètre annulant avec un système permettant d'introduire des perturbations calibrées typiques du vol en formation et de les corriger grâce a des boucles actives. Cette thèse s'inscrit dans le cadre de la conception, de l'étude et du développement d'un des sous-systèmes du banc : le module de recombinaison interférométrique. Ce module est dérivé du concept de l'interféromètre de "Mach-Zehnder Modifié" proposé par Serabyn et al. (2001). Il a la particularité de combiner à la fois les faisceaux scientifiques permettant de faire de l'interférométrie annulante et les faisceaux du système de métrologie, ceci afin de minimiser les chemins différentiels entre les deux voies

Interférométrie annulante pour l exoplanétologie

Depuis maintenant 15 ans, le domaine de la détection d exoplanètes s est largement développé. L utilisation de méthodes de détection, indirectes d abord, a permis de découvrir pas moins de 420 nouveaux mondes , parfois surprenants. Forts de cela, les scientifiques cherchent maintenant à caractériser ces exoplanètes. Ainsi des projets spatiaux, se basant sur la méthode de l interférométrie annulante, ont pour but de réaliser des spectres de planètes géantes et telluriques. Compte tenu de la complexité de ces missions, la nécessité de tester, d abord en laboratoire, certains aspects technologiques comme le principe de l interférométrie annulante, est rapidement apparue. En 2006, le CNES a décidé de mener une étude R&D de la charge utile d un interféromètre annulant à deux télescopes (typiquement l instrument PEGASE). Ainsi, le banc de test PERSEE (Pegase Experiment for Research and Stabilization of Extreme Extinction) est né. Ce banc est le premier banc de test couplant un interféromètre annulant avec un système permettant d introduire des perturbations calibrées typiques du vol en formation et de les corriger grâce à des boucles actives. Cette thèse s inscrit dans le cadre de la conception, de l étude et du développement d un des sous-systèmes du banc : le module de recombinaison interférométrique. Ce module est dérivé du concept de l interféromètre de Mach-Zehnder Modifié proposé par Serabyn et al. (2001). Il a la particularité de combiner à la fois les faisceaux scientifiques permettant de faire de l interférométrie annulante et les faisceaux du système de métrologie, ceci afin de minimiser les chemins différentiels entre les deux voies.For the past 15 years, the field of exoplanets detection has considerably expanded. Detection methods, first indirect, have allowed to discover no less than 420 new worlds , sometimes astonishing. Scientists want now to characterize these exoplanets (particularly telluric ones) and Nulling interferometry is one of the direct detection methods assessed to do this. Within this framework, several space based projects are developed. Due to the complexity of these missions, it is necessary to test, first in laboratory, some technological aspects, as the principle of nulling interferometry. In 2006, CNES has decided to conduct an R&D on the payload of a two-telescope space based interferometer (typically the PEGASE instrument). Thus, the PERSEE test bench (Pegase Experiment for Research and Stabilization of Extreme Extinction) was conceived. The idea of PERSEE is to couple a nulling interferometer with a free flying simulator allowing introducing realistic disturbances and correcting them with active internal loops controlling the optical path difference and the pointing. This PhD work presents the design, the study and the development of one of the sub-systems of the bench: the beam combiner. This module is a new version of the Modified Mach-Zehnder beam combiner proposed by Serabyn et al. (2001). It has the particularity to combine the nuller and the Fringe Tracker system in order to minimize differential paths.ORSAY-PARIS 11-BU Sciences (914712101) / SudocMEUDON-Observatoire (920482302) / SudocSudocFranceF

PERSEE: description of a new concept for nulling interferometry recombination and OPD measurement

International audienceNulling interferometry requires, among other things, a symmetric recombination module and an optical path difference control system. The symmetric recombination stage has been particularly studied over the last ten years and several concepts are now well known. One of them is the "Modified Mach Zehnder" (MMZ) interferometer, proposed by Serabyn and Colavita (2001) [1]. In this paper, we describe a new version of the MMZ beam combiner which provides a deep null signal in the science channel and, at the same time, phase-sensitive signals in the so-called co-phasing channel. From the latter, accurate optical path difference measurements can be derived. This beam combiner works in the 0.8 to 3.3 mum spectral range (0.8 to 1.5 mum for the co-phasing channel and 1.65 to 3.3 mum for the science channel). Both optical functions can be implemented in the same device thanks to an original optical design involving dedicated phase shifts. In this paper, we describe its principle and detail the optical and mechanical design

Spectral simulations of 67P/Churyumov-Gerasimenko in the range of VIRTIS/Rosetta

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Spectral simulations of 67P/Churyumov-Gerasimenko in the range of VIRTIS/Rosetta

International audienc

Spectral simulations of 67P/Churyumov-Gerasimenko in the range of VIRTIS/Rosetta

International audienc