PLATO (PLAnetary Transits and Oscillations of stars)1 is the M3 class ESA mission dedicated to the discovery
and study of extrasolar planetary systems by means of planetary transits detection. PLATO Payload Camera
units are integrated and vibrated at CSL before being TVAC tested for thermal acceptance and performance
verification at 3 different test facilities (SRON, IAS and INTA). 15 of the 26 Flight Cameras were integrated,
tested and delivered to ESA for integration by the Prime between June 2023 and June 2024, with the remaining
flight units to be tested by the end of 2024. In this paper, we provide an overview of our serial testing approach,
some of the associated challenges, key performance results and an up-to-date status on the remaining planned
activities.
KEYWORDS: Cameras, Space operations, Stars, Design, Data processing, Control systems, Planets, Scanning tunneling microscopy, Satellites, X band, Exoplanets, Astronomical telescopes, Space telescopes
PLATO (PLAnetary Transits and Oscillations) mission is a space-based optical multi-camera photometer mission of the European Space Agency (ESA) to identify and characterize exoplanets and their hosting stars using two main techniques: planetary transit and asteroseismology. Selected as the M3 (third Medium class mission) of the ESA 2015-2025 Cosmic Vision program, PLATO is scheduled to launch end of 2026 and designed for 4 years of nominal observation. The PLATO spacecraft is composed of a Service Module and a Payload Module. The Service Module comprises all the conventional spacecraft subsystems and the sun shield with attached solar arrays. The Payload Module consists of a highly stable optical bench, equipped with 26 optical cameras covering a global field of view of > 2232deg2. The PLATO spacecraft data is complemented by ground-based observations and processed by a dedicated Science Ground Segment. We describe the mission and spacecraft architecture and provide a view of the current status of development.
The Focal Plane Assembly (FPA) in optics is the unit located at the focal plane position of the different optical instruments. Each FPA hosts the detectors on support structures and associated interfaces (I/Fs) as quasi-static mounts which assemble them with the rest of the mechanical parts of the instrument; the electronic I/Fs as the flexi-cables connecting each detector to the Front End Electronics (FEE); and the thermomechanical I/Fs as the Thermal Straps (TS) attaching these devices in order to dissipate their heat. Due to the critical repeatability aspect of the different models (QM, FM, FS) in the space missions, each FPA must be identical with stringent specifications, which includes strict opto-mechanical positioning tolerances. These very demanding metrological requirements only can be reached under a special industrialization of alignment processes and an automatic metrology verification thanks to a high-precision, high-performance non-contact vision dimensional measurement system with micrometric or even better accuracy. After the in-lab conditions assembly activities, a better alignment attending the acquired knowledge and lessons learned of past cases have been used to implement improvements into the alignment of new large FPAs for acceptance testing. The optical metrological performances verification carried out before and after the acceptance test campaign of FPAs has been successfully passed and several Flight Models (FMs) have been assembled by the AIV Team from the Spanish Instituto Nacional de Técnica Aeroespacial (INTA) following ECSS (European Cooperation for Space Standardization) policy, and have been delivered to ESA’s subcontractors for performing the formal acceptance processes at instrument level under increasingly tight schedule constraints.
The preparation of the different institutes (IAS, SRON and INTA at France, Netherlands and Spain, respectively) for being ready for testing the PLATO (Planetary transits and oscillation of starts) telescopes (PLATO CAMs) under working condition has been a long trip full of requirements updates and needs adaptation. For this ESA mission devoted to the Exoplanets detection and partial characterization together to the associated star activity evaluation through its astroseismology, 26 telescopes are going to be mounted on the same platform. There are 24 identical ‘normal’ and 2 ‘fast’ PLATO CAMs, all formed by four CCDs mounted on the focal plane assembly (FPA), the front end electronics (FEE) used for completing the detection chain, and optics and optomechanics that forms the telescopes optical unit (TOU). After their alignment and integration verification done at CSL, they are sent to the corresponding institute for running at the best focus temperature at which the telescope provides the best image the performance checks required for considering them properly characterized and ready to be installed in their final configuration at OHB. In this paper, a brief summary on the main details of the tests carried out at INTA on the PLATO CAM flight model (FM) number three are reported on. In addition, preliminary results obtained together to the rest of the consortium and related to the telescopes capabilities are included for the particular case of such first flight model tested at INTA.
PLATO (PLAnetary Transits and Oscillation of Starts) is the third medium class mission of ESA devoted to exoplanets detection and partial characterization together to the associated star activity evaluation through its astroseismology. It is consisting on 26 telescopes mounted on the same platform, 24 called ‘normal’ and composed of four full-frame CCDs and 2 ‘fast’ composed of four frame-transfer CCDs mounted on their respective focal plane assemblies (FPAs). For completing the detection chain, they are using their front-end electronics (FEE), being the optics and opto-mechanics of the telescope optical unit (TOU) the last element of the PLATO-CAMs. In the framework of the mission development, the PLATO-CAMs, after their proper alignment and assembly, are required to be calibrated and tested on simulated working conditions. INTA is one of the European institutions (together to IAS and SRON, in France and Netherlands, respectively), in which such telescopes testing and calibration is carried out by simulating the L2 conditions corresponding to the PLATO-CAMs working environment. In this paper, the setup preparation for PLATO-CAM calibration and testing details are reported on, including design, and fabrication of the different elements, all the ground support equipment (GSE) required for the PLATO-CAMs full characterization and performance evaluation. In addition, the results on the first model tested at INTA, the engineering model (EM) are summarized.
PLATO (Planetary Transits and Oscillation of Starts) will be used for finding the hugest amount of exoplanets ever found and to characterize them together to the associated star activity evaluation through its astroseismology. For such a purpose, 26 telescopes will be mounted on the same platform: 24 of them, called ‘normal’ and composed of four full-frame CCDs and the last 2, known as ‘fast’ composed of four frame-transfer CCDs. In both cases, CCDs will be installed on their respective focal plane assemblies (FPAs). For completing the detection chain, they are using their front end electronics (FEE), being the optics and opto-mechanics of the telescope optical unit (TOU) the last element of the PLATO CAMs. As a part of the payload development and assembly and integration and test, the PLATO CAMs are required to be calibrated and tested on simulated working conditions. INTA is one of the European institutions (together to IAS and SRON, in France and Netherlands, respectively), in which such telescopes testing and calibration is carried out. As a part of the product assurance activities, a protocol for reaching safe conditions on the telescopes during TVAC testing under any unexpected and dangerous event happed was prepared. In this paper, we are describing the need of the protocol activation for answering to one of the worst events that could be present during a TVAC testing campaign: an unexpected power outage making the vacuum pumps critically fail. The room conditions recovering in a safe way is reported on.
PLATO is an exoplanet hunting mission of the European Space Agency. It is a medium-class mission, with a launch foreseen in 2026. Its prime objective is to uncover Earth-sized planets residing in their habitable zone. The payload consists in 26 cameras with a very wide field of view. These cameras consist in a Telescope Optical Unit, aligned at ambient and characterised at the operational temperature, and a Focal Plane Array bearing the detectors, and delivered after coupling with the Front End Electronics. In this contribution, we report on the alignment of the Engineering Model camera of Plato, i.e., the input metrology, the mechanical alignment of the optical unit with the focal plane array, the test environment and the optical characterisation throughout the process until the integrity check after delivery to the cryo-vacuum testing facility where the camera underwent a thorough performance demonstration. We also give a detailed description of the bolting process and the associated error budget.
The PLAnetary Transits and Oscillations of stars mission (PLATO) is an ESA M3 mission planned to detecting and characterizing extrasolar planetary systems as Earth-like exoplanets orbiting around the habitable zone of bright solartype stars. PLATO consists of 26 cameras (CAM) mounted on the same instrument platform in order to cover a large field of view (FoV) with the highest possible photon detection statistics. Each PLATO CAM consists of a telescope Optical Unit (TOU), the FPA, and the detector read-out Front End Electronics (FEE). The FPA is the structure located at the focal plane position of the CAM that supports four identical CCDs and the mechanical interface parts to match with the TOU and FEE. Due to the critical repeatability aspect of the mission, each FPAs must be identical with very stringent specifications which includes strict opto-mechanical positioning tolerances. Also the number of FPAs that have to be manufactured, integrated and tested at the same time requires a special space industrialization process and an optimized metrology verification due to the very restrictive design and schedule constraints. In order to solve this challenge a flight-representative QM has been developed in order to validate a manufacturing, assembly, integration and verification (AIV) on-ground processes. As well, an innovative metrology system has being developed for improving the alignment and verification under the tightly AIV requirements before, during and after a proper qualified campaign in a very demanding environment. INTA has adapted into an ISO6 cleanroom facility a high accuracy and vast performance non-contact CNC vision dimensional measuring system, and has developed a Ground Support Equipment (GSE) for a real-time alignment step in order to reach that requirements.
PLATO is an exoplanet hunting mission from the European Space Agency. It is a medium-class mission, with a launch foreseen in 2026. Its prime objective is to uncover Earth-sized planets residing in the habitable zone of their host star. The payload consists of 26 cameras with a very wide field-of-view. While the operational temperature of the cameras will be -80°C, the focal plane of each camera will be integrated with its telescope assembly (bearing the optics) at room temperature. The degradation of the optical quality at ambient, combined with the detector dark current and with the very high accuracy required from the alignment process bring a number of interesting challenges. In the present article, we review the alignment concept, present optical simulations of the measurements at ambient along with their analysis, and present an error budget for the optical measurements. The derivation of this error budget is easily applicable to all optical measurements to be performed during the alignment, i.e. the definition of the best image plane at the operational temperature and the optical alignment itself, at room temperature.
Raman Laser Spectrometer (RLS) is one of the Pasteur Payload instrument of the ExoMars 2020 mission, within the ESA’s Aurora Exploration Program. RLS is mainly composed by SPU (Spectrometer Unit), iOH (Internal Optical Head), and ICEU (Instrument Control and Excitation Unit), and will analyse Mars surface and sub-surface crushed samples by Raman spectroscopy. For the RLS Flight Model (FM) verification campaign, an end-to-end quick functional test was developed to evaluate the instrument performances stability. This test consists on a comparison of the centre pixel and the FWHM (Full Width at Half Maximum) of a set of Ne calibration lamp peaks, and was decided to be done before and after ever risky activity (transport, thermal tests, etc.) In the course of the end-to-end functional test carried out on RLS FM as part of the pre-delivery checks, an increment on the FWHM calibration lamp peaks was observed. Such performance variation was also noted to be dependent on the way the SPU thermal strap was assembled and the environmental conditions (P and T) in which the spectra were acquired. For that reason, a new SPU thermal strap assembly procedure was decided to be designed in order to ensure no extra negativeeffect was going to appear during the RLS FM installation on the ALD (Analytical Laboratory Drawer) and the instrument flight operation. In this paper, a deep exploration of the conditions in which such “de-focus” (probably due to an excessive thermal gradient between SPU structure and CCD) appears is carried out, demonstrating that the new thermal strap assembly procedure minimizes an incidental extra de-focus appearance during RLS installation on the ALD.
PLATO, PLAnetary Transits and Oscillation of stars, is an ESA mission mainly devoted to survey the Galaxy searching for and characterizing Earth-like exoplanets, and their host stars. This will be achieved using continuous and extremely accurate photometry for both exoplanetary transits and asteroseismology analysis. Current design plans to mount 26 cameras in the same instrument bench in order to cover a large field of view with the highest possible photon statistics. Each PLATO camera consists of the telescope (TOU, Telescope Optical Unit), the focal plane assembly (FPA), and the detector and camera read out electronics (FEE). Four CCDs (Charge Coupled Devices) will be included in each FPA, which implies a really delicate assembly and integration verification (AIV) process due to the stringent scientific requirements breakdown into hard engineering ones (among others, CCDs co-alignment in terms of tip and tilt and roll with respect to the optical axis). In the following lines, the FPA current opto-mechanical design is briefly presented and an integration process conceptual proposal is reported on, discussing the error budgets associated to the main requirements to be verified during FPAs AIV, and the main results obtained during the prototype first AIV round.
J. Moreno, E. Vielba, A. Manjón, A. Motos, E. Vázquez, E. Rodríguez, D. Saez, M. Sengl, J. Fernández, G. Campos, D. Muñoz, M. Mas, A. Balado, G. Ramos, C. Cerruti, M. Pajas, I. Catalán, M. Alcacera, A. Valverde, P. Pflueger, I. Vera
This paper describes the thermo-mechanical design of the Focal Plane Assembly (FPA) of the PLAnetary Transits and Oscillations of stars (PLATO) Instrument, developed by INTA and LIDAX. This is an ESA program with OHB as industry prime. In terms of assembly, alignment, and operational stability very demanding needs are required by a huge focal plane composed of four CCDs to assure the proper performance. This is translated into a complex thermomechanical design which shall be also focused on the correct production approach of the main parts involved, including several processes, and taking into account the number of cameras, and therefore Focal Plane Assemblies, to be produced (26). Part of these challenges, and their associated risks, are mitigated by means of the development of a totally representative prototype, which is currently finishing the integration phase and facing the test campaign.
In the framework of the ESA’s Aurora Exploration Programme and, in particular, of the ExoMars mission, the Raman Laser Spectrometer (RLS) will be in charge of performing out planetary Raman spectroscopy for the first time. The instrument is located inside the Rover at the Analytical Drawer (ALD) and will analyze powdered samples obtained from the Martian subsurface in order to determine the geochemistry content and elemental composition of the minerals under study. After the RLS instrument successful qualification, the Flight Model (FM) development and the acceptance verification activities started. Among the different units RLS is composed on, i.e. its three main units that are interconnected by optical fibers and electrical harness, iOH (Internal Optical Head), SPU (Spectrometer Unit) and ICEU (Instrument control and Excitation Unit) which also contains the Raman excitation laser diode, iOH FM information can be found in this paper. RLS iOH unit is in charge of focusing the Raman excitation signal onto the sample, receiving the Raman signal emitted by the sample and focusing this signal in the output optical fiber that is directly connected to SPU unit. As for the rest of RLS instrument FM subunits, and before their final assembly and system level tests, RLS iOH FM exhaustive and complete characterization process was carried out, not only at room conditions but also at relevant environmental conditions: vacuum condition along the operational temperature range with acceptance margins (from -50 to 8ºC). In this paper, and after to carry out the RLS iOH FM proper integration and alignment process, the activities accomplished during the performance verification and the obtained results are reported on
In the framework of the ESA EarthCare Mission, an atmospheric LIDAR (ATLID) was included as a payload. CAS is the co-alignment system of such a LIDAR instrument, the system responsible of guaranteeing the proper alignment of the projected laser beam and the reflected light collected. Within CAS, in which a consortium leaded by ASTRIUM France is working in, as well as CRISA (electronics) and LIDAX (mechanical engineering), INTA is in charge of the development of the instrumentation to be used on ground (on ground support equipments, OGSEs) needed for the proper electro-optical characterization.
Due to the difficulty in studying the upper layer of the troposphere by using ground-based instrumentation, the conception of a space-orbit atmospheric LIDAR (ATLID) becomes necessary. ATLID born in the ESA’s EarthCare Programme framework as one of its payloads, being the first instrument of this kind that will be in the Space. ATLID will provide vertical profiles of aerosols and thin clouds, separating the relative contribution of aerosol and molecular scattering to know aerosol optical depth. It operates at a wavelength of 355 nm and has a high spectral resolution receiver and depolarization channel with a vertical resolution up to 100m from ground to an altitude of 20 km and, and up to 500m from 20km to 40km. ATLID measurements will be done from a sun-synchronous orbit at 393 km altitude, and an alignment (co-alignment) sensor (CAS) is revealed as crucial due to the way in which LIDAR analyses the troposphere. As in previous models, INTA has been in charge of part of the ATLID instrument co-alignment sensor (ATLID-CAS) electro-optical characterization campaign. CAS includes a set of optical elements to take part of the useful signal, to direct it onto the memory CCD matrix (MCCD) used for the co-alignment determination, and to focus the selected signal on the MCCD. Several tests have been carried out for a proper electro-optical characterization: CAS line of sight (LoS) determination and stability, point spread function (PSF), absolute response (AbsRes), pixel response non uniformity (PRNU), response linearity (ResLin) and spectral response. In the following lines, a resume of the flight model electrooptical characterization campaign is reported on. In fact, results concerning the protoflight model (CAS PFM) will be summarized. PFM requires flight-level characterization, so most of the previously mentioned tests must be carried out under simulated working conditions, i.e., the vacuum level (around 10-5 mbar) and temperature range (between 50°C and -30°C) that are expected during ATLID Space operation.
Raman Laser Spectrometer (RLS) is the Pasteur Payload instrument of the ExoMars mission, within the ESA’s Aurora Exploration Programme, that will perform for the first time in an out planetary mission Raman spectroscopy. RLS is composed by SPU (Spectrometer Unit), iOH (Internal Optical Head), and ICEU (Instrument Control and Excitation Unit). iOH focuses the excitation laser on the samples (excitation path), and collects the Raman emission from the sample (collection path, composed on collimation system and filtering system). Its original design presented a high laser trace reaching to the detector, and although a certain level of laser trace was required for calibration purposes, the high level degrades the Signal to Noise Ratio confounding some Raman peaks. So, after the bread board campaign, some light design modifications were implemented in order to fix the desired amount of laser trace, and after the fabrication and the commitment of the commercial elements, the assembly and integration verification process was carried out. A brief description of the iOH design update for the engineering and qualification model (iOH EQM) as well as the assembly process are briefly described in this papers. In addition, the integration verification and the first functional tests, carried out with the RLS calibration target (CT), results are reported on.
In the last two decades, Spain has built up a strong IR community which has successfully contributed to space instruments, reaching Co-PI level in the SPICA mission (Space Infrared Telescope for Cosmology and Astrophysics). Under the SPICA mission, INTA, focused on the SAFARI instrument requirements but highly adaptable to other missions has designed a cryogenic low dissipation filter wheel with six positions, taking as starting point the past experience of the team with the OSIRIS instrument (ROSETTA mission) filter wheels and adapting the design to work at cryogenic temperatures. One of the main goals of the mechanism is to use as much as possible commercial components and test them at cryogenic temperature. This paper is focused on the design of the filter wheel, including the material selection for each of the main components of the mechanism, the design of elastic mount for the filter assembly, a positioner device designed to provide positional accuracy and repeatability to the filter, allowing the locking of the position without dissipation. In order to know the position of the wheel on every moment a position sensor based on a Hall sensor was developed. A series of cryogenic tests have been performed in order to validate the material configuration selected, the ball bearing lubrication and the selection of the motor. A stepper motor characterization campaign was performed including heat dissipation measurements. The result is a six position filter wheel highly adaptable to different configurations and motors using commercial components. The mechanism was successfully tested at INTA facilities at 20K at breadboard level.
The Exoplanet Characterisation Observatory (EChO) mission was one of the proposed candidates for the European Space Agency’s third medium mission within the Cosmic Vision Framework. EChO was designed to observe the spectra from transiting exoplanets in the 0.55-11 micron band with a goal of covering from 0.4 to 16 microns. The mission and its associated scientific instrument has now undergone a rigorous technical evaluation phase and we report here on the outcome of that study phase, update the design status and review the expected performance of the integrated payload and satellite.
EChO (Exoplanet atmospheres Characterization Observatory), a proposal for exoplanets exploration space mission, is considered the next step for planetary atmospheres characterization. It would be a dedicated observatory to uncover a large selected sample of planets spanning a wide range of masses (from gas giants to super-Earths) and orbital temperatures (from hot to habitable). All targets move around stars of spectral types F, G, K, and M. EChO would provide an unprecedented view of the atmospheres of planets in the solar neighbourhood. The consortium formed by various institutions of different countries proposed as ESA M3 an integrated spectrometer payload for EChO covering the wavelength interval 0.4 to 16 µm. This instrument is subdivided into 4 channels: a visible channel, which includes a fine guidance system (FGS) and a VIS spectrometer, a near infrared channel (SWiR), a middle infrared channel (MWiR), and a long wave infrared module (LWiR). In addition, it contains a common set of optics spectrally dividing the wavelength coverage and injecting the combined light of parent stars and their exoplanets into the different channels. The proposed payload meets all of the key performance requirements detailed in the ESA call for proposals as well as all scientific goals. EChO payload is based on different spectrometers covering the spectral range mentioned above. Among them, SWiR spectrometer would work from 2.45 microns to 5.45 microns. In this paper, the optical and mechanical designs of the SWiR channel instrument are reported on.
Gonzalo Ramos Zapata, Tomás Belenguer, Ana Balado, Javier Barandiarán, Iñaki Armendáriz, Manuel Reina, César Arza, Santiago Rodríguez, Maria Ángeles Alcacera, José Fernández, Elisa Muñoz, Giovanna Tinetti, Paul Eccleston, Bruce Swinyard, Marc Ferlet, Ian Bryson, María Rosa Zapatero
EChO, a space mission for exoplanets exploration, is considered the next step for planetary atmospheres
characterization. It will be a dedicated observatory to uncover a large selected sample of planets spanning a
wide range of masses (from gas giants to super-Earths) and orbital temperatures (from hot to habitable). All
targets move around stars of spectral types F, G, K, and M. EChO will provide an unprecedented view of the
atmospheres of planets in the solar neighbourhood.
The consortium formed by various institutions of different countries is proposing an integrated
spectrometer payload for EChO covering the wavelength interval 0.4 to 16 µm. This instrument is subdivided
into 4 channels: a visible channel, which includes a fine guidance system (FGS) and a VIS spectrometer, a
near infrared channel (SWiR), a middle infrared channel (MWiR), and a long wave infrared module (LWiR).
In addition, it contains a common set of optics spectrally dividing the wavelength coverage and injecting the
combined light of parent stars and their exoplanets into the different channels. The proposed payload meets all
of the key performance requirements detailed in the ESA call for proposals as well as all scientific goals.
EChO payload will be based on different spectrometers covering the spectral range mentioned above.
Among them, SWiR spectrometer will work from 2.45 microns to 5.45 microns. In this paper, the optical and
mechanical designs of the SWiR channel instrument, including the evolution of the different trades followed
and the current identification of critical points, are reported on.
KEYWORDS: Sensors, Spectroscopy, Space telescopes, Telescopes, Planets, Stars, Space operations, Mid-IR, Long wavelength infrared, Short wave infrared radiation
The Exoplanet Characterisation Observatory (EChO) is a space mission dedicated to undertaking spectroscopy of
transiting exoplanets over the widest wavelength range possible. It is based around a highly stable space platform with a
1.2 m class telescope. The mission is currently being studied by ESA in the context of a medium class mission within
the Cosmic Vision programme for launch post 2020. The payload suite is required to provide simultaneous coverage
from the visible to the mid-infrared and must be highly stable and effectively operate as a single instrument. In this
paper we describe the integrated spectrometer payload design for EChO which will cover the 0.4 to 16 micron
wavelength band. The instrumentation is subdivided into 5 channels (Visible/Near Infrared, Short Wave InfraRed, 2 x Mid Wave InfraRed; Long Wave InfraRed) with a common set of optics spectrally dividing the input beam via dichroics.
We discuss the significant design issues for the payload and the detailed technical trade-offs that we are undertaking to
produce a payload for EChO that can be built within the mission and programme constraints and yet which will meet the
exacting scientific performance required to undertake transit spectroscopy.
F. Rull, A. Sansano, E. Díaz, M. Colombo, T. Belenguer, M. Fernández, V. Guembe, R. Canchal, B. Dávila, A. Sánchez, H. Laguna, G. Ramos, C. González, D. Fraga, P. Gallego, I. Hutchinson, R. Ingley, J. Sánchez, C. Canora, A. Moral, S. Ibarmia, J. A. Prieto, J. A. R. Manfredi, P. Cabo, C. Díaz, A. Jiménez, J. Pla, R. Margoillés
The Raman Laser Spectrometer instrument is included in ExoMars program Pasteur payload and it is focused on the
Mars samples analytical analysis of the geochemistry content and elemental composition of the observed crushed
samples obtained by the Rover.
One of the most critical Units of the RLS is the Spectrometer unit (SPU) that performs Raman spectroscopy technique
and operates in a very demanding environment (operative temperature: from -40 ºC to 6 ºC) with very restrictive design
constraints. It is a very small optical instrument capable to cope with 0.09 nm/pixel of resolution. The selected solution is
based on a single transmisive holographic grating.
At this stage of the project SPU Team is preparing the Conceptual Design Review that will take place at the end of
October 2011.
E. Díaz, A. Moral, C. Canora, G. Ramos, O. Barcos, J. A. Prieto, I. B. Hutchinson, R. Ingley, M. Colombo, R. Canchal, B. Dávila, J. A. R. Manfredi, A. Jiménez, P. Gallego, J. Pla, R. Margoillés, F. Rull, A. Sansano, G. López, A. Catalá, C. Tato
The Raman Laser Spectrometer (RLS) is one of the Pasteur Payload instruments, within the ESA's Aurora Exploration
Programme, ExoMars mission.
The RLS Instrument will perform Raman spectroscopy on crushed powdered samples deposited on a small container
after crushing the cores obtained by the Rover's drill system.
In response to ESA requirements for delta-PDR to be held in mid 2012, an instrument BB programme has been
developed, by RLS Assembly Integration and Verification (AIV) Team to achieve the Technology Readiness level 5
(TRL5), during last 2010 and whole 2011. Currently RLS instrument is being developed pending its CoDR (Conceptual
Design Revision) with ESA, in October 2011.
It is planned to have a fully operative breadboard, conformed from different unit and sub-units breadboards that would
demonstrate the end-to-end performance of the flight representative units by 2011 Q4.
F. Rull, A. Sansano, E. Díaz, C. Canora, A. Moral, C. Tato, M. Colombo, T. Belenguer, M. Fernández, J. A. Manfredi, R. Canchal, B. Dávila, A. Jiménez, P. Gallego, S. Ibarmia, J. A. Prieto, A. Santiago, J. Pla, G. Ramos, C. González
The Raman Laser Spectrometer (RLS) is one of the Pasteur Payload instruments, within the ESA's Aurora Exploration
Programme, ExoMars mission.
The RLS Instrument will perform Raman spectroscopy on crushed powered samples deposited on a small container after
crushing the cores obtained by the Rover's drill system. This is the first time that a Raman spectrometer will be launched
in an out planetary mission.
The Instrument will be accommodated and operate inside the Rover's ALD (Analytical Laboratory Drawer), complying
with COSPAR (Committee on Space Research) Planetary Protection requirements.
The RLS Instrument is composed by the following units: SPU (Spectrometer Unit); iOH: (Internal Optical Head); ICEU (Instrument Control and Excitation Unit).
Other instrument units are EH (Electrical Harness), OH (Optical Harness) and RLS SW On-Board.
The IACAT (IAC Atmosphere and Telescope) Simulator is an Optical Ground Support Equipment which simulates
atmospheric turbulence and reproduces the performance of three very different telescopes: GTC and WHT, located at
the Observatorio Del Roque de los Muchachos in La Palma (Canary Islands), and OGS which is located at the
Observatorio Del Teide in Tenerife (Canary Islands). Its mission is to provide Scientists with the same measurement
conditions as the real telescope but in a friendly laboratory environment, to assist in the development of new adaptive
optics methods based on FPGAs.
The most important telescope characteristics are simulated, such as f number, pupil size and position, magnification,
central obscuration, etc. Up to 13 stellar objects can be created, individually or as binary stars with specific angular
separations down to miliarcseconds.
For the atmosphere simulation, it allows the creation of three different turbulence layers concurrently with different
altitude and wind speed ranges.
Gonzalo Ramos Zapata, Tomás Belenguer Dávila, Carmen Pastor Santos, René Restrepo Gómez, Concepción González Alvarado, Hugo Laguna Hernández, Antonio Astolfi Carbonell, Javier Moreno Raso, Heribert Argelaguet, Javier Serrano
A LED based illumination system in which five Galilean collimation systems have been used is reported
on. It is part of a turbulence simulator for the evaluation of on ground telescopes instrumentation developed
by INTA (optics) and LIDAX (opto-mechanics) for the IAC called IACATS. The illumination requirements
(some visible and infrared lines) allow the use of five different LEDs (red, green, blue and two infrareds). In
order to optimize the illumination level of each wavelength, a Galilean collimating optical configuration was
constructed for each wavelength channel.
The IACATS instrument simulates a scene consisting of a set of different binary stars simulating the
required angular separation between them, ant their spectral characteristics. As a result, a visible and infrared
multi-spectral illumination system has been integrated as a part of the turbulence simulator, and the features
(opto-mechanical) and illumination characteristics are described in the following lines.
IACATS is an atmospheric turbulence, stars and telescope simulator for the evaluation of on ground
telescopes instrumentation developed by INTA (optics) and LIDAX
(opto-mechanics) for the IAC (Instituto
de Astrofísica de Canarias).
Three telescopes have been simulated, matching the f number, focal plane, and optical interface of the
actual telescopes. An optical breadboard was designed and built containing the required opto-mechanics for
simulating the telescopes, and various levels of turbulence required.
In addition to the telescope simulator optics, a set of three phase plates have been procured and
conveniently combined in order to reproduce the atmospheric turbulence required by the IAC. A wave front
sensor has been also included in order to evaluate the deformation that the phase plates, or the simulated
turbulence, produce in the wave front coming from the illumination system and star simulator. Finally, a
specific illumination system was developed including different working wavelengths in order to fulfil the
requirements. The description of the illumination system itself has been done in a separate publication.. In the
following lines, the characteristics of the IACATS instrument as well as the results obtained from the AIV
(Assembly and Integration Verification) process are reported on.
The CTU (Cryogenics Translation Unit) is a low range (±1 mm) high resolution (<50 nm) translation unit to be used at
cryogenic temperature (20K). The unit is a multipurpose device capable of fine closed loop positioning. This device can
be used as active element in IR Instrumentation for compensating thermo-elastic deformation moving optical elements
or sensors.
CTU motion system is based in thin flexures deformation to assure repeatability and moves in closed loop mode by
means of a fine linear actuator and a calibrated non contact capacitive sensor.
This paper describes main design features, how cryogenic testing of main requirements was carried out (including
methodologies used for calibration and submicron verification), tested performances, and main lesson learned during the
development.
IMaX current status is reported on. IMaX, the Imaging Magnetograph eXperiment developed for a
Spanish consortium for the SUNRISE Mission, is a payload that will work simultaneously as a high
sensitivity polarimeter, a high resolving spectral power, and a near diffraction limited imager. Once every
mechanical element has been purchased, the assembly, integration, alignment and verification processes
(AIV process) has been carried out successfully. After a brief description of the IMaX opto-mechanical
elements that have been received, the integration sequence as well as the main results obtained during the
AIV process are presented.
Basically, AIV process consists on the opto-mechanical components assembly on the Optical Bench
(OB), the optical elements assembly on the previously integrated optomechanics, the alignment and
orientation of the opto-mechanical components, and the two-channels quality evaluation that allows to
leave the opto-mechanical components ready for the cameras integration and IMaX performance tests
characterization. Actually, the most relevant results related to the AIV process as well as the IMaX
performance firsts tests are presented.
In this work, the optical measurement system employed to evaluate the performance of a 6 degrees of
freedom (dof) positioning mechanism under cryogenic conditions is explored. The mechanism, the flight
model of three translations and three rotations positioning mechanism, was developed by the Spanish
company SENER (for ASTRIUM) to fulfil the high performance requirements from ESA technology
preparatory program for the positioning of a secondary mirror within the GAIA Astrometric Mission. Its
performance has been evaluated under vacuum and temperature controlled conditions (up to a 10-6mbar
and 100K) at the facilities of the Space Instrumentation Laboratory (LINES) of the Aerospace Technical
Nacional Institute of Spain (INTA).
After the description of the 'alignment tool' developed to compare a fixed reference with the optical
signal corresponding to the movement under evaluation, the optical system that allows measuring the
displacements and the rotations in the three space directions is reported on. Two similar bread-boards
were defined and mounted for the measurements purpose, one containing two distancemeters, in order to
measure the displacements through the corresponding axis, and an autocollimator in order to obtain the
rotations on the plane whose normal vector is the axis mentioned before, and other one containing one
distancemeter and one autocollimator. Both distancemeter and autocollimator measurements have been
combined in order to extract the information about the accuracy of the mechanism movements as well as
their repeatability under adverse environmental conditions.
In this work, the optical evaluation of a mechanism for space applications under vacuum and
temperature controlled conditions at the facilities of the Space Instrumentation Laboratory (LINES) of the
Aerospace Technical Nacional Institute of Spain (INTA) is reported. The mechanism was developed by
the Spanish company SENER to fulfill the high performance requirements from ESA technology
preparatory program for GAIA Astrometric Mission; in particular, a five degrees of freedom (dof), three
translations and two rotations positioning mechanism for the secondary mirror of the GAIA instrument.
Both interferometric tests and autocollimator measurements have been combined in order to extract
the information about the accuracy of the mechanism movements as well as their repeatability under
adverse environmental conditions: vacuum and thermal controlled conditions, up to a 10-6mbar and 100K.
The scope of this paper will cover the measurements concept selection, the presentation of verification
activities, the results of such dedicated optical measurements, the correlation with the mechanical models
and a brief description of the design process followed to meet the test requirements.
In this work, it is described the Imaging Magnetograph eXperiment, IMaX, one of the three postfocal instruments of
the Sunrise mission. The Sunrise project consists on a stratospheric balloon with a 1 m aperture telescope, which will fly
from the Antarctica within the NASA Long Duration Balloon Program.
IMaX will provide vector magnetograms of the solar surface with a spatial resolution of 70 m. This data is relevant
for understanding how the magnetic fields emerge in the solar surface, how they couple the photospheric base with the
million degrees of temperature of the solar corona and which are the processes that are responsible of the generation of
such an immense temperatures.
To meet this goal IMaX should work as a high sensitivity polarimeter, high resolution spectrometer and a near
diffraction limited imager. Liquid Crystal Variable Retarders will be used as polarization modulators taking advantage of
the optical retardation induced by application of low electric fields and avoiding mechanical mechanisms. Therefore, the
interest of these devices for aerospace applications is envisaged. The spectral resolution required will be achieved by
using a LiNbO3 Fabry-Perot etalon in double pass configuration as spectral filter before the two CCDs detectors. As well
phase-diversity techniques will be implemented in order to improve the image quality.
Nowadays, IMaX project is in the detailed design phase before fabrication, integration, assembly and verification.
This paper briefly describes the current status of the instrument and the technical solutions developed to fulfil the
scientific requirements.
The Imaging MAgnetograph eXperiment, IMaX, is one of the three postfocal instruments of the Sunrise mission. The
Sunrise project consists of a stratospheric balloon with a 1 m aperture telescope, which will fly from the Antarctica
within the NASA Long Duration Balloon Program.
IMaX should work as a diffraction limited imager and it should be capable to carry out polarization measurements
and spectroscopic analysis with high resolution (50.000-100.000 range).
The spectral resolution required will be achieved by using a LiNbO3 (z-cut) Fabry-Perot etalon in double pass
configuration as spectral filter.
Up to our knowledge, few works in the literature describe the associated problems of using these devices in an
imager instrument (roughness, off-normal incidence, polarization sensitivity...). Because of that, an extensive and
detailed analysis of etalon has been carried out. Special attention has been taken in order to determine the wavefront
transmission error produced by the imperfections of a real etalon in double pass configuration working in collimated
beam. Different theoretical models, numeric simulations and experimental data are analysed and compared obtaining a
complete description of the etalon response.
A holographic hybrid sol-gel material with excellent values of diffraction efficiency, index modulation and high photosensitivity (up to 93%, 10-3, and 5 x 10-3 cm2/mJ, respectively) is reported. Moroever, a high angular selectivity has been achieved $9 = 0.0967°) through the selection of the adequate nanoporous silica supporting matrix. Such a value has allowed to first demonstrate the capability of angular multiplexing in a holographic sol-gel media (up to five volume holograms with a resultant M/# of 0.83 in a preliminary approach). Shrinkage during UV curing processes has also been determined in order to evaluate how accurate can be the retrieval of the recorded data.
A photoconductive sol-gel material based on the incorporation of polyvinyl carbazole (PVK) and 2,4,7-trinitro-9-fluorenone (TNF) within a silica matrix is reported. Unmatched photosensitive as large as 10-10 cm/ΩW has been found at moderate applied electric fields (20 V/μm). The optimization of the concentration balance between the functional component (the TNF/PVK molar ratio percent) has resulted in a 300-fold increase of the photocurrent efficiency (Φ). The study of photcoductivity of sol-gel materials prepared with different PVK contents has confirmed the unneeded use of massive photoconductive materials to obtain optimum performance.
This work describes how the sol-gel process can be a useful approach for the preparation of hybrid materials showing either holographic as well as photorefractive properties. The composition of the holographic and photorefractive materials prepared through the sol-gel approach are completely based on their respective multi-functional polymer analogues, but in the polymer acting as host matrix which is replaced by a nanoporous silica matrix. Such a replacement infers an overall improvement in both the optical and the mechanical properties of the material. The goodness of the properties found for either the holographic as well as the photorefractive materials demonstrate the validity of these new synthetic routes for the preparation of optical recording materials.
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