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Acceso Abierto
The PLATO mission
(Springer Nature Link, 2025-04-21) Rauer, Heike; Aerts, Conny; Cabrera, Juán; Deleuil, Magali; Erikson, Anders; Gizon, Laurent; Goupil, Mariejo; Heras, Ana; Walloschek, Thomas; Lorénzo Álvarez, José; Marliani, Filippo; Martín García, César; Mas Hesse, José Miguel; O´Rourke, Laurence; Osborn, Hugh; Pagano, Isabella; Piotto, Giampaolo; Pollacco, Don; Ragazzoni, Roberto; Ramsay, Gavin; Udry, Stéphane; Appourchaux, Thierry; Benz, Willy; Brandeker, Alexis; Güdel, Manuel; Janot Pacheco, Eduardo; Kabath, Petr; Kjeldsen, Hans; Min, Michiel; Santos, Nuno; Smith, Alan; Suarez, Juan Carlos; Werner, Stephanie; Aboudan, Alessio; Abreu, Manuel; Acuña, Lorena; Adams, Moritz; Adibekyan, Vardan; Affer, Laura; Agneray, François; Agnor, Craig; Aguirre Børsen Koch, Victor; Ahmed, Saad; Aigrain, Suzanne; Al Bahlawan, Ashraf; De los Angeles Alcacera Gil, Ma; Alei, Eleonora; Alencar, Silvia; Alexander, Richard; Alfonso Garzón, Julia; Alibert, Yann; Alende Prieto, Carlos; Almeida, Leonardo; Alonso Sobrino, Roi; Altavilla, Giuseppe; Althaus, Christian; Álvarez Trujillo, Luis Alonso; Amarsi, Anish; Von Eiff, Matthias Ammler; Amôres, Eduardo; Andrade, Laerte; Antoniadis Karnavas, Alexandros; Antonio, Carlos; Aparico del Moral, Beatriz; Appolloni, Mateo; Arena, Claudio; Armstrong, David; Aroca Aliaga, José; Asplund, Martín; Audenaert, Jeoen; Auricchio, Natalia; Avelino, Pedro; Baeke, Ann; Baillié, Kevin; Balado, Ana; Ballber Balagueró, Pau; Balestra, Andrea; Ball, Warrick; Ballans, Herve; Ballot, Jerome; Barban, Caroline; Barbary, Gaële; Barbieri, Mauro; Barceló Fortaleza, Sebastià; Barker, Adrian; Barklem, Paul; Barnes, Sydney; Barrado Navascues, David; Barragan, Oscar; Baruteau, Clément; Basu, Sarbani; Baudin, Frederic; Baumeister, Philipp; Bayliss, Daniel; Bazot, Michael; Beck, Paul; Belkacem, Kevin; Bellinger, Earl; Benatti, Serena; Benomar, Othman; Bérard, Diae; Bergemann, María; Bergomi, María; Bernardo, Pierre; Biazzo, Katia; Bignamini, Andrea; Bigot, Lionel; Billot, Nicolas; Binet, Martín; Biondi, David; Biondi, Federico; Birch, Aaron; Bisch, Bertram; Bluhm Ceballos, Paz Victoria; Bódi, Attila; Bognár, Zsófia; Boisse, Isabelle; Bolmont, Emeline; Bonanno, Alfio; Bonavita, Mariangela; Bonfanti, Andrea; Bonfils, Xavier; Bonito, Rosaria; Bonomo, Aldo Stefano; Börner, Anko; Boro Saikia, Sudeshna; Borreguero Martín, Elisa; Borsa, Francesco; Borsato, Luca; Bossini, Diego; Bouchy, Francois; Boué, Gwenaël; Boufleur, Rodrigo; Boumier, Patrick; Bourrier, Vincent; Bowman, Dominic; Bozzo, Enrico; Bradley, Louisa; Bray, John; Bressan, Aessandro; Breton, Sylvain; Brienza, Daniele; Brito, Ana; Brogi, Matteo; Brown, Beverly; Brown, David; Sacha Brun, Allan; Bruno, Giovanni; Bruns, Michael; Buchhave, Lars; Bugnet, Lisa; Buldgen, Gaël; Burgess, Patrick; Busatta, Andrea; Busso, Giogia; Buzasi, Derek; Caballero, José; Cabral, Alexandre; Cabrero Gómez, Juan Francisco; Calderone, Flavia; Cameron, Robert; Cameron, Andrew; Campante, Tiago; Campos Gestal, Néstor; Canto Martins, Bruno Leonardo; Cara, Christophe; Carone, Ludmila; Carrasco, Josep Manuel; Casagrande, Luca; Casewell, Sarah; Cassisi, Santi; Castellani, Marco; Castro, Matthieu; Catala, Claude; Catalán Fernández, Irene; Catelan, Márcio; Cegla, Heather; Cerruti, Chiara; Cessa, Virginie; Chadid, Merieme; Chaplin, William; Charpinet, Stephane; Chiappini, Cristina; Chiarucci, Simone; Chiavassa, Andrea; Chinellato, Simonetta; Chirulli, Giovanni; Christensen Dalsgaard, Jørgen; Church, Ross; Claret, Antonio; Clarke, Cathie; Claudi, Riccardo; Clermont, Lionel; et., al.; European Commission (EC); European Research Council (ERC); Agencia Estatal de Investigación (AEI)
PLATO (PLAnetary Transits and Oscillations of stars) is ESA’s M3 mission designed to detect and characterise extrasolar planets and perform asteroseismic monitoring of a large number of stars. PLATO will detect small planets (down to <2R) around bright stars (<11 mag), including terrestrial planets in the habitable zone of solar-like stars. With the complement of radial velocity observations from the ground, planets will be characterised for their radius, mass, and age with high accuracy (5%, 10%, 10% for an Earth-Sun combination respectively). PLATO will provide us with a large-scale catalogue of well-characterised small planets up to intermediate orbital periods, relevant for a meaningful comparison to planet formation theories and to better understand planet evolution. It will make possible comparative exoplanetology to place our Solar System planets in a broader context. In parallel, PLATO will study (host) stars using asteroseismology, allowing us to determine the stellar properties with high accuracy, substantially enhancing our knowledge of stellar structure and evolution. The payload instrument consists of 26 cameras with 12cm aperture each. For at least four years, the mission will perform high-precision photometric measurements. Here we review the science objectives, present PLATO‘s target samples and fields, provide an overview of expected core science performance as well as a description of the instrument and the mission profile towards the end of the serial production of the flight cameras. PLATO is scheduled for a launch date end 2026. This overview therefore provides a summary of the mission to the community in preparation of the upcoming operational phases.
Acceso Abierto
Detection of visible-wavelength aurora on Mars
(Science, 2025-05-14) Knutsen, Elise; McConnochie, Timothy; Lemmon, M. T.; Donaldson, Chris; Francis, Raymond; Legett, Carey; Viet, Shayla; Soret, Lauriane; Toledo, D.; Apéstigue, Víctor; Witasse, Olivier; Montmessin, F.; Jolitz, Rebecca; Schneider, Nicolas; Tamppari, L. K.; Cousin, Agnes; Wiens, Roger; Maurice, Sylvestre; Bell, James; Forni, Olivier; Lasue, Jeremie; Pilleri, Paolo; Bertrand, T.; Patel, P.; Schröder, Susanne; Curry, Shannon; Lee, Christina; Rahmati, Ali; National Aeronautics and Space Administration (NASA); Belgian National Fund for Scientific Research; Jet Propulsion Laboratory; Norges Forskningsråd
Mars hosts various auroral processes despite the planet’s tenuous atmosphere and lack of a global magnetic field. To date, all aurora observations have been at ultraviolet wavelengths from orbit. We describe the discovery of green visible-wavelength aurora, originating from the atomic oxygen line at 557.7 nanometers, detected with the SuperCam and Mastcam-Z instruments on the Mars 2020 Perseverance rover. Near–real-time simulations of a Mars-directed coronal mass ejection (CME) provided sufficient lead-time to schedule an observation with the rover. The emission was observed 3 days after the CME eruption, suggesting that the aurora was induced by particles accelerated by the moving shock front. To our knowledge, detection of aurora from a planetary surface other than Earth has never been reported, nor has visible aurora been observed at Mars. This detection demonstrates that auroral forecasting at Mars is possible, and that during events with higher particle precipitation, or under less dusty atmospheric conditions, aurorae will be visible to future astronauts.
Acceso Abierto
Methane precipitation in ice giant atmospheres
(EDP Sciences, 2025-02-04) Toledo, D. ; Rannou, P.; Irwin, P.; De Batz de Trenquelléon, B.; Roman, Michael , M.; Apéstigue, Víctor; Arruego, Ignacio; Yela González, Margarita; Agencia Estatal de Investigación (AEI)
Context. Voyager-2 radio occultation measurements have revealed changes in the atmospheric refractivity within a 2–4 km layer near the 1.2-bar level in Uranus and the 1.6-bar level in Neptune. These changes were attributed to the presence of a methane cloud, consistent with the observation that methane concentration decreases with altitude above these levels, closely following the saturation vapor pressure. However, no clear spectral signatures of such a cloud have been detected thus far in the spectra acquired from both planets. Aims. We examine methane cloud properties in the atmospheres of the ice giants, including vertical ice distribution, droplet radius, precipitation rates, timescales, and total opacity, employing microphysical simulations under different scenarios. Methods. We used a one-dimensional (1D) cloud microphysical model to simulate the formation of methane clouds in the ice giants. The simulations include the processes of nucleation, condensation, coagulation, evaporation, and precipitation, with vertical mixing simulated using an eddy-diffusion profile (Keddy). Results. Our simulations show cloud bases close to 1.24 bars in Uranus and 1.64 bars in Neptune, with droplets up to 100 µm causing high settling velocities and precipitation rates (∼370 mm per Earth year). The high settling velocities limit the total cloud opacity, yielding values at 0.8 µm of ∼0.19 for Uranus and ∼0.35 for Neptune, using Keddy = 0.5 m2 s−1 and a deep methane mole fraction (μCH4) of 0.04. In addition, lower Keddy or μCH4 values result in smaller opacities. Methane supersaturation is promptly removed by condensation, controlling the decline in μCH4 with altitude in the troposphere. However, the high settling velocities prevent the formation of a permanent thick cloud. Stratospheric hazes made of ethane or acetylene ice are expected to evaporate completely before reaching the methane condensation level. Since hazes are required for methane heterogeneous nucleation, this suggests either a change in the solid phase properties of the haze particles, inhibiting evaporation, or the presence of photochemical hazes.
Acceso Abierto
Infrared spectroscopy of astrophysical ice analogues at oblique angles
(Oxford University Press, 2025-02-26) González Díaz, Cristobal, C.; Carrascosa, H.; Muñoz Caro, G. M.; Agencia Estatal de Investigación (AEI)
In astrochemical exploration, infrared (IR) spectroscopy is vital for understanding the composition and structure of ice in various space environments. This article explores the impact of incident angles on IR spectroscopy, focusing on molecular components present in interstellar and circumstellar ice mantles such as CO, CO 2 , H 2 O, CH 3 OH, NH 3 , CH 4 , H 2 S. The experiment involves changing the angle at which the IR beam hits the surface used for ice deposition. It is important to measure the density of the ice layer accurately, especially for experiments that involve using different angles in IR spectroscopy. Furthermore, the experimental methodology allowed us to derive the effective refraction index values in the IR range for each ice component. Existing corrections typically consider geometric configurations but o v erlook the refractiv e inde x of the ice ( n ), a factor dependent on ice composition. The study reveals that the incident angle and the refractive index, determine the path length of the IR beam across the ice sample. This insight challenges conventional corrections, impacting the integrated absorption values of the IR bands and column densities. In addition, for certain ice components, variations in the incidence angle affect the longitudinal (LO) and transverse (TO) optical modes of the ice, leading to observable changes in the IR band profiles that provide information on the amorphous or crystalline structure of the ice. The practical implications of this work apply to experimental setups where normal IR measurements are unfeasible. Researchers using, for example, the standard 45 ◦ angle for IR spectroscopy, will benefit from a more accurate estimation of ice column density.
Acceso Abierto
Multilevel Validation of Direct Sampling Time-Domain Measuring Receivers
(IEEE, 2025-09-05) Struzhko, Ivan; García Bermúdez, Marc; Solé-Lloveras, Jordi; Añón Cancela, M.; Hartman, Tom; Azpurua, Marco A.; Leferink, Frank; European Research Council (ERC)
Although the time-domain approach to electromagnetic interference evaluation offers numerous advantages, including shorter test duration and multichannel acquisition, its practical adoption remains limited. This is mainly because existing standards, such as CISPR 16-1-1, do not explicitly address direct sampling time-domain measuring receivers or define specific calibration and validation procedures for them. While several studies have demonstrated successful use cases, a comprehensive validation of such systems has not yet been performed. This article presents multilevel experimental validations of time-domain measuring receivers, focusing on the direct sampling approach and oscilloscope-based implementations. First, meta-comparisons of FFT-based receivers are made using calibration data obtained from certificates of accredited laboratories. Then, controlled signal sources with known time and spectral characteristics are used to cross-check with different measuring receiver models. Finally, several instruments are benchmarked with respect to their standard detector outputs when measuring the emissions of a power converter while spread spectrum techniques are used. The results show good agreement between the measuring receivers in the time domain and the tested conventional receivers in the frequency domain within the standard error, even though the complexity of the measured signals is different.
Acceso Abierto
Design, development, and qualification of a broadband compact S-band antenna for a CubeSat Constellation
(MDPI - Multidisciplinary Digital Publishing Institute, 2025-02-18) Sánchez-Sevilleja, Saray; Poyatos Martinez, David; Masa-Campos, J.L.; Aragón Fernández, Víctor Miguel; Rodríguez Prieto, José Antonio; Santiago Pé, Amaia; Agencia Estatal de Investigación (AEI)
An S-band antenna has been designed, developed, measured, space-qualified, and integrated into the INTA ANSER satellite constellation and the future ANSER-AT mission. This antenna will be part of the space-to-ground communication link for the constellation, which consists of one Leader and two Followers. The novel antenna, mounted on the Leader, has been designed and manufactured with materials and processes specifically tested for space. It features dual circular polarization over a wide band without requiring a phase-shifting network, making it very compact and straightforward. Additionally, its gain patterns are highly stable within the desired band, improving its link capacity compared to the UHF monopole alternative used in the previous Leader. Currently, the antenna has been qualified and installed on INTA’s Leader-S, set to launch in January 2025, as well as on the future ANSER-AT mission.
Acceso Abierto
Characterization of 3D-printed cordierite-rGO nanocomposites for aerospace applications
(Scipedia, 2025-06-26) Esguerra Arce, Ingrid; García Juárez, Álvaro; Garcia-Martinez, Juan; Hidalgo García, Javier; Plaza Gallardo, Borja; Giménez Pérez, Raquel; Ulargui, S.; Berges Serrano, Cristina; Herranz Sánchez-Cosgalla, Gemma; García-Martínez, María; Agencia Estatal de Investigación (AEI)
One of the most critical challenges in the aerospace industry is the mismatch in the coefficient of thermal expansion (CTE) between optical components in satellites and their metallic supports, which limits system reliability and performance. Ceramic materials, due to their superior thermal properties, offer a potential solution however, their adoption has been limited by the complexity of their geometries and conventional manufacturing constraints. Additive manufacturing has opened new opportunities for the development of advanced ceramics, including ceramic matrix composites (CMCs). Within the framework of the AERORECORD-3D project, funded by the Spanish Ministry of Science and Innovation, ceramic cordierite-based supports reinforced with reduced graphene oxide (rGO) have been developed for aerospace applications. In this study, cordierite nanocomposites with varying rGO contents were successfully fabricated via 3D printing. Their thermal, electrical, and mechanical properties were evaluated to assess their performance, exploring their potential as advanced materials for demanding space applications. This work represents a significant step toward the implementation of 3D-printed ceramic nanocomposites by combining innovative materials with advanced additive manufacturing technologies.
Acceso Abierto
Monte Carlo Evaluation of Uncertainties of UV Spectra Measured With Brewer Spectroradiometers
(Advancing Earth and Space Sciences (AGU), 2023-12-26) González, Carmen; Vilaplana, Jose Manuel; Serrano, Antonio; Agencia Estatal de Investigación (AEI)
Precise spectral ultraviolet (UV) measurements are needed to ensure human protection as well as to support scientific research. Quantifying the uncertainty of the UV spectra recorded is crucial to evaluate the quality of the measurements which is needed, in turn, for the assessment of their reliability. However, for double-monochromator spectroradiometers, the analytical derivation of this uncertainty is a challenging task due to the difficulties involved in propagating individual uncertainties. Under these circumstances, a Monte Carlo simulation is a reliable alternative as it does not require the calculation of partial derivatives and considers both nonlinear effects and correlations in the data. In the present study, the uncertainty of the spectral UV irradiance measured by a Brewer MKIII spectrophotometer is evaluated using a Monte Carlo approach. This instrument belongs to the National Institute of Aerospace Technology and has successfully participated in several international campaigns, which ensures its precise calibration. The average expanded uncertainty (k = 2) of the global UV irradiance measured by this instrument varies between 10% at 300 nm and 7% at 363 nm. At shorter wavelengths, it increases sharply due to thermal and electronic noise as well as wavelength misalignment. The results indicate that a Brewer spectrophotometer is suitable for climatological studies and model validation. Nevertheless, a substantial reduction of these uncertainties might be required for accurately detecting long-term UV trends. Although the study focused on a Brewer spectrometer, the methodology used for the uncertainty analysis is general and can be adapted to most UV spectroradiometers.
Acceso Abierto
Validation of the GUM uncertainty framework and the Unscented transformation for Brewer UV irradiance measurements using the Monte Carlo method
(Elsevier, 2024-08-08) González, Carmen; Vilaplana, Jose Manuel; Parra Rojas, Francisco; Serrano, Antonio; Agencia Estatal de Investigación (AEI)
The uncertainty evaluation of spectral ultraviolet (UV) irradiance measurements is usually performed following the recommendations set by the GUM, the standard for uncertainty evaluation in metrology. In particular, the GUM uncertainty framework (GUF) is applied. Due to the difficulties in the propagation of uncertainties, it is standard practice to neglect the non-linearity of the irradiance model. To verify this assumption, the GUF is validated using the Monte Carlo method (MCM), as recommended by the GUM. As an alternative to these methods, an Unscented transformation (UT) has also been implemented and validated with the MCM. The data used are the UV scans recorded by a Brewer MKIII spectroradiometer at El Arenosillo Observatory. Evaluation of the spectral ratios between the combined standard uncertainties provided by the GUF, the UT, and the MCM showed that the agreement between the three methodologies is satisfactory.
Acceso Abierto
Evaluation of the uncertainty of the spectral UV irradiance measured by double- and single-monochromator Brewer spectrophotometers
(European Geosciences Union, 2025-10-30) González, Carmen; Vilaplana, Jose Manuel; Redondas, Alberto; López Solano, Javier; San Atanasio, José M.; Kift, Richard; Smedley, Andrew; Babal, Pavel; Díaz, Ana; Jepsen, Nis; Gacitúa, Guisella; Serrano, Antonio; Agencia Estatal de Investigación (España)
Brewer instruments are robust, widely used instruments that have been monitoring global solar ultraviolet (UV) irradiance since the 1990s, playing a key role in UV research. Unfortunately, the uncertainties of these measurements are rarely evaluated due to the difficulties involved in characterising the instruments. This evaluation is essential to determine the quality of the measurements as well as their comparability to other datasets. In this study, eight double- and two single-monochromator Brewers are characterised, and the uncertainty of their global UV measurements is estimated using the Monte Carlo method. This methodology is selected because it provides reliable uncertainty estimations and considers the nonlinearity of certain steps in the UV processing algorithm. The combined standard uncertainty depends on the Brewer instrument, varying between 2.5 % and 4 % between 310 and 350 nm. These uncertainties arise primarily from radiometric stability, cosine correction, and the uncertainty of the lamp used during calibration. At shorter wavelengths, the differences between single- and double-monochromator Brewers increase. For example, at 296 nm and a solar zenith angle (SZA) of 40°, the relative uncertainties of single Brewers range between 11 % and 23 %, whereas double Brewers have uncertainties of 3 %–5 %. As the measured wavelength decreases, the correction of stray light (for single Brewers), dark counts, and noise become the dominant sources of uncertainty. These results indicate that the accuracy of fully characterised double Brewers is sufficient for biological studies and trend detection, whereas single Brewers might be limited to wavelengths and SZAs below 305 nm and 70°, respectively.
Acceso Abierto
Comparison of global UV spectral irradiance measurements between a BTS CCD-array and a Brewer spectroradiometer
(European Geosciences Union, 2022-07-15) González, Carmen; Vilaplana, Jose Manuel; Bogeat Sánchez-Piqueras, José Antonio; Serrano, Antonio
Spectral measurements of UV irradiance are of great importance for protecting human health as well as for supporting scientific research. To perform these measurements, double monochromator scanning spectroradiometers are the preferred devices thanks to their linearity and stray-light reduction. However, because of their high cost and demanding maintenance, CCD-array-based spectroradiometers are increasingly used for monitoring UV irradiance. Nevertheless, CCD-array spectroradiometers have specific limitations, such as a high detection threshold or stray-light contamination. To overcome these challenges, several manufacturers are striving to develop improved instrumentation. In particular, Gigahertz-Optik GmbH has developed the stray-light-reduced BTS2048-UV-S spectroradiometer series (hereafter “BTS”). In this study, the long-term performance of the BTS and its seasonal behavior, regarding global UV irradiance, was assessed. To carry out the analysis, BTS irradiance measurements were compared against measurements from the Brewer MK-III #150 scanning spectrophotometer during three campaigns. A total of 711 simultaneous spectra, measured under cloud-free conditions and covering a wide range of solar zenith angles (SZAs; from 14 to 70∘) and UV indexes (from 2.4 to 10.6), were used for the comparison. During the three measurement campaigns, the global UV spectral ratio BTS / Brewer was almost constant (at around 0.93) in the 305–360 nm region for SZAs below 70∘. Thus, the BTS calibration was stable during the whole period of study (∼ 1.5 years). Likewise, it showed no significant seasonal or SZA dependence in this wavelength region. Regarding the UV index, a good correlation between the BTS and the Brewer #150 was found, i.e., the dynamic range of the BTS is comparable to that of the Brewer #150. These results confirm the quality of the long-term performance of the BTS array spectroradiometer in measuring global UV irradiance.
Restringido
Machine Learning Methods Applied to Broadband Electromagnetic Characterization
(2025-11) Cublier Martínez, Aymar; Frövel de la Torre, Jorge; Sanz, Ruy; Plaza Gallardo, Borja; Poyatos Martinez, David
The introduction of composite materials in the aerospace industry has yielded improved performance and better strength-to-weight ratio in space platforms' design. The ubiquity of these materials in today's space missions involves, among other things, a deep understanding of their electromagnetic (EM) properties. To study the EM properties of dielectric materials, several machine learning algorithms such as Deep Neural Networks (DNN) and ensemble learning methods (Random Forest, Gradient Boosting) are implemented as extraction methods for EM characterization in free space. First, the training and testing datasets for the supervised learning algorithms are generated using EM simulations with given permittivity and loss tangent. Second, an existing high precision test bench is used at INTA's Computational and Applied Electromagnetics Laboratory (CAEM-Lab) for gathering data to feed the prediction models at the validation stage over a broad frequency range of 2.6−40GHz. Finally, results are contrasted with conventional methods for complex permittivity extraction, such as analytical based solutions and optimization related methods. Other features like temperature can be added to the models to study the EM properties of materials at cryogenic temperatures for space applications.
Acceso Abierto
CHEOPS ground segment: Systems and automation for mission and science operations
(Elsevier, 2025-10-30) Heitzmann, Alexis; González Bonilla, María José; Bekkelien, Anja; Akinsanmi, Babatunde; Beck, Mathias; Billot, Nicolas; Broeg, Christopher; Deline, Adrien; Ehrenreich, David; Fortier, Andrea; Kirsch, Marcus; Lendl, Monika; Alfaro Llorente, Nuria; Fernández de Bobadilla Vallano, Naiara, Naiara; Fuentes Tabas, María; Maldonado, Anthony; Vega Carrasco, Eva; Modrego Contreras, David
The CHaracterising ExOPlanet Satellite (CHEOPS) is the first European Space Agency (ESA) small-class mission. It has been performing photometric astronomical observations with a particular emphasis on exoplanetary science for the past five years. A distinctive feature of CHEOPS is that the responsibility for all operational aspects of the mission lies with the CHEOPS consortium rather than ESA. As a result, all subsystems, their architecture, and operational processes have been independently developed and tailored specifically to CHEOPS. This paper offers an overview of the CHEOPS operational subsystems, the design, and the automation framework that compose the two main components of the CHEOPS ground segment: the Mission Operations Center (MOC) and the Science Operations Center (SOC). This comprehensive description of the CHEOPS workflow aims to serve as a reference and potential source of inspiration for future small and/or independent space missions.
Acceso Abierto
On the Use of FDTD for HIRF Validation and Certification
(The Electromagnetic Academy (USA), 2012-06-12) Gutierrez, Guadalupe G.; Fernández Romero, Sergio; Álvarez, Jesús ; González García, Salvador; Pascual Gil, Enrique; Ministerio de Ciencia e Innovación (MICINN); European Commission (EC); Junta de Andalucía
Preparing the 3D-geometry models to perform electromagnetic compatibility (EMC) numerical simulations can be tedious and time consuming. Furthermore, the need to include the test setup in the models, in order to validate the software, by comparing the numerical results with the measured data, may lead to unwieldy simulation models with often una ordable computational costs. In this paper, we provide strategies for optimizing and simplifying the modeling process, together with guidelines for achieving the most unfavorable case in the simulation of EMC problems, as required for a certi cation process. A test case from the European FP7 HIRF-SE project is analyzed in this paper as an example of how to identify the unnecessary elements for the simulation, while retaining the essential physics of the problem.
Restringido
A shielding effectiveness prediction method for coupled reverberant cavities validated on a real object
(Taylor and Francis online, 2015-07-25) Fernández Romero, Sergio; Gutierrez, Guadalupe G.; González, Iván; Ministerio de Economía y Competitividad (MINECO)
In the last years, different works on reverberant microwave propagation and high frequency coupling inside oversized structures have been published in order to make progress in the investigation of wireless systems and electromagnetic threats. In this paper, a new focus to the shielding effectiveness (SE) prediction using the reverberation microwave propagation formalism has been applied to a real complex object attaining very good agreement with the measured data obtained from nested reverberation chamber method. The used formalism is the combination of the simplified propagation model with the updated and more accurate formulation for cavity Q-factor and energy dissipation mechanisms. A very wide frequency range, from 500 MHz to 40 GHz, has been analyzed, which allows us to draw conclusions about how each parameter affects the final SE result at different frequency bands. Furthermore, a tuning study has been performed taking into account the tolerance in the most important parameters, such as the cavity size, the Q-factor, the main dissipation energy mechanisms, and the aperture shapes.
Restringido
Validation procedure of low level coupling tests on real aircraft structure
(IEEE Xplore, 2012-12-31) Fernández Romero, Sergio; López Morales, Andrés; Añón Cancela, M.; Gutierrez, Guadalupe G.; European Commission (EC)
This paper describes the analysis of the experimental test results obtained during the low level swept coupling (LLSC) and low level direct drive (LLDD) tests on FALCON 7X horizontal tail plane provided by EADS-CASA. These techniques are evaluated during the aircraft high intensity radiated field (HIRF) certification process and in the scope of European Community's FP7 HIRF SE project. The analysis of low level test results shall be performed to estimate the influence of the test setup with particular regard to the in-flight coupling configuration. For this reason, finite difference time domain (FDTD) 3D computations have been used to determine the relationship between free field external radiation and skin current in different illumination angles and polarizations. Finally, after validation by comparison of the measured and computed skin current, measured bundle current are related to measured skin currents, to provide the transfer function link to the external field.
Restringido
Prediction of the maximum electric field level inside a metallic cavity using a quality factor estimation
(Taylor and Francis online, 2014-06-26) Fernández Romero, Sergio; Gutierrez, Guadalupe G.; González, Iván; Ministerio de Economía y Competitividad (MINECO)
This paper presents a method for predicting the maximum electric field level inside a metallic cavity making use of the quality factor (Q) estimation. This calculation requires a two-step approach combining several theoretical models which can be found in the literature. A very good agreement in the frequency range between 100 MHz and 40 GHz has been achieved with the data obtained from the validation of two reverberation chambers made of different conductive materials. The wide frequency band analyzed permits us to draw conclusions about the main contributions in the cavity Q and their relationships with the maximum electric field level. This paper also describes and identifies the relationships between the antenna parameters and dissipation mechanisms vs. frequency for the different models. This estimation could be used to calculate a possible EMC threat of a spurious emission of EM signals which could produce a susceptibility problem in other equipments installed in the same cavity.
Acceso Abierto
Validation of Aura Microwave Limb Sounder Ozone by ozonesonde and lidar measurements
(AGU Publishing, 2007-12-15) Jiang, T. B.; Froidevaux, L.; Lambert, A.; Livesey, N. J.; Read, W. G.; Waters, J. W.; Bojkov, B. ; Leblanc, T.; Mcdermid, I. S.; Godin-Beekmann, S.; Filipiak, M. J.; Harwood, R. S.; Fuller, R. A.; Daffer, W. H.; Drouin, B. J.; Cofield, R. E.; Cuddy, D. T.; Jarnot, R. F.; Knosp, B. W.; Perun, V. S.; Schwartz, M. J.; Snyder, W. V.; Stek, P. C.; Thurstans, R. P.; Wagner, P. A.; Allaart, M.; Andersen, S. B.; Bodeker, G.; Calpini, B.; Claude, H.; Coetzee, G.; Davies, J.; De Backer, H.; Dier, H.; Fujiwara, M.; Johnson, B.; Kelder, H.; Leme, N. P.; König Langlo, G.; Kyrö, Esko; Laneve, G.; Fook, L. S.; Merrill, J.; Morris, G.; Newchurch, M.; Oltmans, S.; Parrondo, María Concepción; Posny, F.; Schmidlin, F.; Skrivankova, P.; Stubi, R.; Tarasick, D.; Thompson, A.; Thouret, V.; Viatte, P.; Vömel, H.; Von der Gathen, P.
We present validation studies of MLS version 2.2 upper tropospheric and stratospheric ozone profiles using ozonesonde and lidar data as well as climatological data. Ozone measurements from over 60 ozonesonde stations worldwide and three lidar stations are compared with coincident MLS data. The MLS ozone stratospheric data between 150 and 3 hPa agree well with ozonesonde measurements, within 8% for the global average. MLS values at 215 hPa are biased high compared to ozonesondes by ∼20% at middle to high latitude, although there is a lot of variability in this altitude region. Comparisons between MLS and ground-based lidar measurements from Mauna Loa, Hawaii, from the Table Mountain Facility, California, and from the Observatoire de Haute-Provence, France, give very good agreement, within ∼5%, for the stratospheric values. The comparisons between MLS and the Table Mountain Facility tropospheric ozone lidar show that MLS data are biased high by ∼30% at 215 hPa, consistent with that indicated by the ozonesonde data. We obtain better global average agreement between MLS and ozonesonde partial column values down to 215 hPa, although the average MLS values at low to middle latitudes are higher than the ozonesonde values by up to a few percent. MLS v2.2 ozone data agree better than the MLS v1.5 data with ozonesonde and lidar measurements. MLS tropical data show the wave one longitudinal pattern in the upper troposphere, with similarities to the average distribution from ozonesondes. High upper tropospheric ozone values are also observed by MLS in the tropical Pacific from June to November.
Restringido
Unprecedented Arctic ozone loss in 2011
(Springer Nature, 2011-10-02) Manney, Gloria; Santee, Michelle; Rex, Markus; Livesey, Nathaniel; Pitts, Michael; Veefkind, Pepijn; Nash, Eric; Wohltmann, Ingo; Lehmann, Ralph; Froidevaux, Lucien; Poole, Lamont; Schoeberl, Mark; Haffner, David; Davies, Jonathan; Dorokhov, Valery; Gernandt, Hartwig; Johnson, Bryan; Kivi, Rigel; Kyrö, Esko; Larsen, Niels; Levelt, Pieternel; Makshtas, Alexander; Mcelroy, Thomas; Nakajima, Hideaki; Parrondo, María Concepción; Tarasick, David; Von der Gathen, Peter; Walker, Kaley; Zinoviev, Nikita
Chemical ozone destruction occurs over both polar regions in local winter–spring. In the Antarctic, essentially complete removal of lower-stratospheric ozone currently results in an ozone hole every year, whereas in the Arctic, ozone loss is highly variable and has until now been much more limited. Here we demonstrate that chemical ozone destruction over the Arctic in early 2011 was—for the first time in the observational record—comparable to that in the Antarctic ozone hole. Unusually long-lasting cold conditions in the Arctic lower stratosphere led to persistent enhancement in ozone-destroying forms of chlorine and to unprecedented ozone loss, which exceeded 80 per cent over 18–20 kilometres altitude. Our results show that Arctic ozone holes are possible even with temperatures much milder than those in the Antarctic. We cannot at present predict when such severe Arctic ozone depletion may be matched or exceeded.
Acceso Abierto
Mid-winter lower stratosphere temperatures in the Antarctic vortex: comparison between observations and ECMWF and NCEP operational models
(EGU European Geosciences Union, 2007-01-24) Parrondo, María Concepción; Yela González, Margarita; Gil, M.; Von der Gathen, P.; Ochoa, H.
Radiosonde temperature profiles from Belgrano (78° S) and other Antarctic stations have been compared with European Centre for Medium-Range Weather Forecasting (ECMWF) and National Centers for Environmental Prediction (NCEP) operational analyses during the winter of 2003. Results show good agreement between radiosondes and NCEP and a bias in the ECMWF model which is height and temperature dependent, being up to 3°C too cold at 80 and 25–30 hPa, and hence resulting in an overestimation of the predicted potential PSC areas. Here we show the results of the comparison and discuss the potential implications that this bias might have on the ozone depletion computed by Chemical Transport Models based on ECMWF temperature fields, after rejecting the possibility of a bias in the sondes at extreme low temperatures.

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