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Acceso Abierto
Time Domain Simulation of Common Mode Ferrite Chokes at System Level
(Institute of Electrical and Electronics Engineers, 2023-09-11) Gascón Bravo, Alberto; García, S. G.; Muñoz Manterola, Alejandro; Añón Cancela, M.; Moreno, Roberto; Tekbaş, Kenan; Angulo, L. D.; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Ciencia e Innovación (MICINN); European Commission (EC); Universidad de Granada (UGR)
This article introduces a comprehensive methodology for analyzing common-mode (CM) ferrite chokes in time-domain (TD) methods, employing lumped dispersive loads, and validates it through a typical test setup for cable crosstalk assessment. The analysis begins with the experimental characterization of CM choke material properties using a coaxial line fixture to obtain its constitutive parameters. Subsequently, a simplified lumped dispersive convolutional model is obtained, representing the impedance of the ferrite when placed on a location on the cable. The first approach adopts a multiconductor transmission line (MTL) model for the cables, solving them by a finite-difference (FDTD) space-time scheme. The second approach utilizes the classical full-wave Yee-FDTD method in conjunction with the thin-wire Holland model for cables. The accuracy of the proposed methods is evaluated by comparing simulations performed with MTL-FDTD and Holland-Yee FDTD, to experimental measurements, and results obtained with the the frequency-domain finite element method using a 3-D model of the ferrite with its constitutive parameters. Finally, the validity and performance of the methodologies are critically discussed.
Acceso Abierto
Uncertainty budget in microwave high-power testing
(Institute of Electrical and Electronics Engineers, 2023-09-22) García Patrón, Martín; Rodríguez, Manuel; Ruiz-Cruz, Jorge A.; Montero, Isabel; Instituto Nacional de Técnica Aeroespacial (INTA)
Space-borne radio frequency (RF) systems must cope with hard qualification procedures, including the evaluation of high-power handling capability of equipment for space applications. Whatever the electrical parameter is being measured, the general rule of thumb throughout a verification process is to check whether the system can operate up to certain thresholds, which are defined to ensure total reliability for the mission along its operative lifetime. Therefore, assessing and reducing the uncertainty linked to their measurement are mandatory issues as it directly affects the accuracy of the qualification process and hence the safety of the whole space mission. This article presents a novel comprehensive study of all variables affecting measurement uncertainty for high RF power test activities. This study is focused on space applications, and, in particular, multipactor testing, because they comprise the largest number of variables. This is not a restricting case; in fact, the outcome of this work is applicable both for space and ground RF applications. As a conclusion, a complete uncertainty for RF high-power testing is obtained, and, where possible, mitigation actions have also been defined.
Acceso Abierto
A Subcell Finite-Difference Time-Domain Implementation for Narrow Slots on Conductive Panels
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-08-03) Ruiz Cabello Núñez, M. D.; Martín Valverde, A. J.; Plaza Gallardo, B.; Frövel, M.; Poyatos Martínez, D.; Rubio Bretones, Amelia C.; Gascón Bravo, Alberto; García, S. G.; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Ciencia e Innovación (MICINN)
Efficiently modeling thin features using the finite-difference time-domain (FDTD) method involves a considerable reduction in the spatial mesh size. However, in real-world scenarios, such reductions can lead to unaffordable memory and CPU requirements. In this manuscript, we present two stable and efficient techniques in FDTD to handle narrow apertures on conductive thin panels. One technique employs conformal methods, while the other utilizes subgridding methods. We validate their performance compared to the classical Gilbert-Holland model and present experimental results in reverberation environments to shed light on these models’ actual confidence margins in real electromagnetic compatibility (EMC) scenarios.
Restringido
Anisotropic magnetoresistance (AMR) instrument to study the Martian magnetic environment from the surface: expected scientific return
(Springer Link, 2023-08-15) Díaz Michelena, M.; Fernández Romero, S.; Adeli, Solmaz; Henrich, Clara; Aspás, Alberto; Parrondo, M. C.; Rivero Rodríguez, Miguel Ángel; Oliveira, Joana S.; Instituto Nacional de Técnica Aeroespacial (INTA); Centros de Excelencia Severo Ochoa, BARCELONA SUPERCOMPUTING CENTER (BSC), SEV2015-0493
The ExoMars programme has the objective to answer to the question of whether life ever existed on Mars. The second mission comprising the Rosalind Franklin rover and Kazachok Surface Platform was designed to focus specifically on the characterization of the environmental parameters which can play an important role for the existence of life on the surface of the planet. One of these parameters is the magnetic field because of its ability of shielding the solar and cosmic radiation. For such characterization, the scientific suite of the Surface Platform counts with two instruments: the Anisotropic MagnetoResistance (AMR) and the MArtIan Ground ElectromagneTic (MAIGRET) instruments. The AMR goal is to characterize both the surface and subsurface and the time-varying magnetic fields, related to the crustal and the external fields respectively, at the ExoMars landing site in Oxia Planum. The operation to achieve these goals includes two phases, the first phase corresponding to the lander descent and the second phase in which the instrument is deployed on the surface. In this work, we simulate the first operations phase using synthetic magnetic field models, assuming that the different crustal units at the landing site might be magnetized. We also perform measurements in our laboratory to simulate the second phase operation of the instrument on the Martian surface. We discuss the capability of interpretation of the instrument, based on the available information of the landing site and the results from our models.
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Experimental and numerical characterization of the Flow around the Mars 2020 Rover
(Aerospace Research Central, 2018-04-30) Bardera, Rafael; García Magariño, A.; Gómez Elvira, J.; Marín Jiménez, M.; Navarro, Sara; Torres Redondo, J.; Carretero, Sara; Sor, Suthyvann; Instituto Nacional de Técnica Aeroespacial (INTA)
The investigation of the environmental factors in Mars atmosphere is one of the issues of the NASA’s Mars Exploration Program about the potential for life on Mars. The future Mars 2020 rover will transport the Mars Environmental Dynamics Analyzer dedicated to obtain meteorological data, as well as other objectives, about wind speed and direction. High-quality wind data are required to build mathematical models of the Mars climate; therefore, powerful techniques are necessary to eliminate flow perturbations produced by the rover presence. The aim of this Paper is the characterization of the flow around the Mars 2020 rover, providing a deep insight into the environmental interaction of the Mars wind with the rover. A comparative study between numerical simulations versus wind-tunnel experimental results is conducted trying to investigate the influence of the rover on the flow measured by the Mars Environmental Dynamics Analyzer wind sensors. This study is addressed to perform an assessment of the reliability of numerical methods in the prediction of this kind of flow in Martian conditions, evaluating its capability to be used in the future to correct wind data coming from the Mars 2020 rover mission. The advancements in the numerical methods as compared with experimental results implies an advancement on the calibration methods in the space wind sensor instrumentation carried in the Mars 2020 rover.
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Mars 2020 Rover Influence on Wind Measurements at Low Reynolds Number
(Aerospace Research Central, 2019-02-11) Bardera, Rafael; García Magariño, A.; Urdiales, María del Mar; Sor, Suthyvann; Instituto Nacional de Técnica Aeroespacial (INTA)
The Mars 2020 rover is the new vehicle dedicated to the Martian surface investigation. This vehicle will transport Mars Environmental Dynamic Analyzer, the new meteorological station, including two wind sensors installed in the camera mast. An experimental characterization was conducted to investigate the influence of the Mars 2020 rover in the Mars Environmental Dynamic Analyzer wind measurements at low Reynolds numbers. Wind tunnel experiments were conducted using a 1:45th scaled model in a wind tunnel specially designed for these experiments. The velocity was measured using laser Doppler anemometry. A method is proposed in this investigation to calculate a correction factor for the data measurements of wind sensors embarked on rovers dedicated to planetary exploration missions. In particular, the method was applied to wind measurements taken by Mars Environmental Dynamic Analyzer in the Mars 2020 rover using the laser Doppler anemometry measurements, and corrections up to 40% in the velocity magnitude and 23 deg in the deflection angle were found.
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Mars 2020 Wind Velocity Measurement Interferences at High Reynolds Numbers
(Aerospace Research Central, 2019-12-29) García Magariño, A.; Bardera, Rafael; Muñoz, Javier; Sor, Suthyvann; Instituto Nacional de Técnica Aeroespacial (INTA)
The Mars Environmental Dynamics Analyzer will be dedicated to getting meteorological data from Mars during NASA’s Mars 2020 rover mission. High-quality Mars atmosphere measurements are required in order to build mathematical models of the climate on a planetary scale. The Mars 2020 rover will be equipped with two wind sensors installed on two separated booms working in active redundancy but producing a mutual aerodynamic interference on one another’s wind measurements. This paper presents a systematic study on the interferences produced by the sensors and the rover body itself when measuring wind velocities in order to get insight to assess the uncertainties produced by this effect.
Acceso Abierto
The diverse meteorology of Jezero crater over the first 250 sols of Perseverance on Mars
(Nature Publishing Group, 2023-01-09) Rodríguez Manfredi, J. A.; De la Torre Juárez, M.; Sánchez Lavega, Agustín; Hueso, R.; Martínez, Germán; Lemmon, M. T.; Newman, C. E.; Munguira, A.; Hieta, M.; Tamppari, L. K.; Polkko, J.; Toledo, D.; Sebastian, D.; Smith, M. D.; Jaakonaho, I.; Genzer, M.; Vicente Retortillo, Á.; Viúdez Moreiras, Daniel; Ramos, M.; Saiz López, A.; Lepinette, A.; Wolff, M.; Sullivan, R. J.; Gómez Elvira, J.; Conrad, P.; Del Río Gaztelurrutia, T.; Murdoch, N.; Arruego, I.; Banfield, D.; Boland, J.; Brown, Adrian Jon; Ceballos, J.; Domínguez Pumar, M.; Espejo, S.; Fairén, A.; Ferrándiz Guibelalde, Ricardo; Fischer, E.; García Villadangos, M.; Giménez Torregrosa, S.; Gómez Gómez, F.; Guzewich, S. D.; Harri, Ari-Matti; Jiménez Martín, Juan José; Jiménez, V.; Makinen, Terhi; Marín Jiménez, M.; Martín Rubio, C.; Martín Soler, J.; Molina, A.; Mora Sotomayor, L.; Navarro, Sara; Peinado, V.; Pérez Grande, I.; Pla García, J.; Postigo, M.; Prieto Ballesteros, O.; Rafkin, S. C. R.; Richardson, M. I.; Romeral, J.; Savijärv, H.; Schofield, J. T.; Torres, J.; Urquí, R.; Apéstigue, Víctor; Zurita, S.; Romero Guzman, Catalina; NASA Jet Propulsion Laboratory (JPL); National Aeronautics and Space Administration (NASA); Instituto Nacional de Técnica Aeroespacial (INTA); European Commission (EC); Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); California Institute of Technology (CIT); Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
NASA’s Perseverance rover’s Mars Environmental Dynamics Analyzer is collecting data at Jezero crater, characterizing the physical processes in the lowest layer of the Martian atmosphere. Here we present measurements from the instrument’s first 250 sols of operation, revealing a spatially and temporally variable meteorology at Jezero. We find that temperature measurements at four heights capture the response of the atmospheric surface layer to multiple phenomena. We observe the transition from a stable night-time thermal inversion to a daytime, highly turbulent convective regime, with large vertical thermal gradients. Measurement of multiple daily optical depths suggests aerosol concentrations are higher in the morning than in the afternoon. Measured wind patterns are driven mainly by local topography, with a small contribution from regional winds. Daily and seasonal variability of relative humidity shows a complex hydrologic cycle. These observations suggest that changes in some local surface properties, such as surface albedo and thermal inertia, play an influential role. On a larger scale, surface pressure measurements show typical signatures of gravity waves and baroclinic eddies in a part of the seasonal cycle previously characterized as low wave activity. These observations, both com
Acceso Abierto
Convective Vortices and Dust Devils Detected and Characterized by Mars 2020
(AGU Advancing Earth and Space Science, 2023-02-10) Hueso, R.; Newman, C. E.; Del Río Gaztelurrutia, T.; Munguira, A.; Sánchez Lavega, A.; Toledo, D.; Arruego, I.; Vicente Retortillo, Á.; Martínez, G.; Lemmon, M. T.; Lorenz, Ralph; Richardson, M. I.; Viúdez Moreiras, Daniel; De la Torre Juárez, M.; Rodríguez Manfredi, J. A.; Tamppari, L. K.; Murdoch, N.; Navarro López, Sara; Gómez Elvira, J.; Baker, M.; Pla García, J.; Harri, Ari-Matti; Hieta, M.; Genzer, M.; Polkko, J.; Jaakonaho, I.; Makinen, Terhi; Stott, Alexander; Mimoun, D.; Chide, B.; Sebastián Martínez, Eduardo; Banfield, D.; Lepinette Malvitte, A.; Apéstigue, Víctor; Gobierno Vasco; Ministerio de Ciencia e Innovación (MICINN); Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Los Alamos National Laboratory (LANL); Arizona State University (ASU); Universities Space Research Association (USRA); NASA Jet Propulsion Laboratory (JPL); Comunidad de Madrid; Academy of Finland (AKA); Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We characterize vortex and dust devils (DDs) at Jezero from pressure and winds obtained with the Mars Environmental Dynamics Analyzer (MEDA) instrument on Mars 2020 over 415 Martian days (sols) (Ls = 6°–213°). Vortices are abundant (4.9 per sol with pressure drops >0.5 Pa correcting from gaps in coverage) and they peak at noon. At least one in every five vortices carries dust, and 75% of all vortices with Δp > 2.0 Pa are dusty. Seasonal variability was small but DDs were abundant during a dust storm (Ls = 152°–156°). Vortices are more frequent and intense over terrains with lower thermal inertia favoring high daytime surface-to-air temperature gradients. We fit measurements of winds and pressure during DD encounters to models of vortices. We obtain vortex diameters that range from 5 to 135 m with a mean of 20 m, and from the frequency of close encounters we estimate a DD activity of 2.0–3.0 DDs km−2 sol−1. A comparison of MEDA observations with a Large Eddy Simulation of Jezero at Ls = 45° produces a similar result. Three 100-m size DDs passed within 30 m of the rover from what we estimate that the activity of DDs with diameters >100 m is 0.1 DDs km−2sol−1, implying that dust lifting is dominated by the largest vortices in Jezero. At least one vortex had a central pressure drop of 9.0 Pa and internal winds of 25 ms−1. The MEDA wind sensors were partially damaged during two DD encounters whose characteristics we elaborate in detail.
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Magnetic Induction-Based Susceptometer: Calibration Procedure for Complex Susceptibility Measurement and Extended Application in Natural Scenarios
(Institute of Electrical and Electronics Engineers, 2023-01-27) Mesa Uña, J. L.; Hernández Ros, C. A.; Díaz Michelena, M.; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Ciencia e Innovación (MICINN); European Commission (EC); Agencia Estatal de Investigación (AEI)
The fast and in situ measurement of the complex magnetic susceptibility stands a potential geological tool for enhanced characterization of rocks and comprehension of the geological context of the landing and exploration sites when used on board planetary rovers. The real part of susceptibility is related to the capability to acquire magnetization and the imaginary part, with resistivity and magnetic energy loss mechanism of rocks. Therefore, the determination of the rocks’ susceptibility provides key information as to the need for the presence of water in the formation of certain minerals, which can be used as one of the rocks selection criteria, in sample return missions. Previous work has been done in the conception of a novel portable instrument, based on magnetic induction, to measure the complex susceptibility of rocks in the context of planetary exploration. The next step is to create a comprehensive calibration procedure to extract magnetic properties information from the direct readings. This work describes a novel instrument calibration methodology. The calibration of the novel instrument comprises a comparative methodology with representative patterns for the real and the imaginary components of the susceptibility. Therefore, the work also includes calibration sample conception, manufacture, and characterization by different techniques.
Acceso Abierto
Dust Devil Frequency of Occurrence and Radiative Effects at Jezero Crater, Mars, as Measured by MEDA Radiation and Dust Sensor (RDS)
(GU Advancing Earth and Space Science, 2023-01-17) Toledo, D.; Arruego, I.; Lemmon, M. T.; Gómez, L.; Montoro, F.; Hueso, R.; Newman, C. E.; Smith, M.; Viúdez Moreiras, Daniel; Martínez, G.; Vicente Retortillo, Á.; Sánchez Lavega, Agustín; De la Torre Juarez, M.; Rodríguez Manfredi, J. A.; Carrasco, I.; Yela González, M.; Jiménez, J. J.; García Menéndez, Elisa; Navarro, Sara; Gómez Elvira, J.; Harri, Ari-Matti; Polkko, J.; Hieta, M.; Genzer, M.; Murdoch, N.; Sebastián, E.; Apéstigue, Víctor; Agencia Estatal de Investigación (AEI); Ministerio de Ciencia e Innovación (MICINN); Ministerio de Economía y Competitividad (MINECO); NASA Jet Propulsion Laboratory (JPL); National Aeronautics and Space Administration (NASA); Gobierno Vasco
The Mars Environmental Dynamics Analyzer, onboard the Perseverance rover, is a meteorological station that is operating on Mars and includes, among other sensors, the radiometer Radiation and Dust Sensor (RDS). From RDS irradiance observations, a total of 374 dust devils (DDs) were detected for the first 365 sols of the mission (Ls = 6°–182°), which along with wind and pressure measurements, we estimated a DD frequency of formation at Jezero between 1.3 and 3.4 DD km−2 sol−1 (increasing as we move from spring into summer). This frequency is found to be smaller than that estimated at the Spirit or Pathfinder landing sites but much greater than that derived at InSight landing site. The maximum in DD frequency occurs between 12:00 and 13:00 local true solar time, which is when the convective heat flux and lower planetary boundary layer IR heating are both predicted to peak in Jezero crater. DD diameter, minimum height, and trajectory were studied showing (a) an average diameter of 29 m (or a median of 25 m) and a maximum and minimum diameter of 132 ± 63.4 and 5.6 ± 5.5 m; (b) an average minimum DD height of 231 m and a maximum minimum-height of 872 m; and (c) the DD migration direction is in agreement with wind measurements. For all the cases, DDs decreased the UV irradiance, while at visible or near-IR wavelengths both increases and decreases were observed. Contrary to the frequency of formation, these results indicate similar DD characteristics in average for the studied period.
Acceso Abierto
Surface Energy Budget, Albedo, and Thermal Inertia at Jezero Crater, Mars, as Observed From the Mars 2020 MEDA Instrument
(AGU Advancing Earth and Space Science, 2023-02) Martínez, G. M.; Sebastián, E.; Vicente Retortillo, Á.; Smith, Michael; Johnson, J. R.; Fischer, E.; Savijärvi, H.; Toledo, D.; Hueso, R.; Mora Sotomayor, L.; Gillespie, H.; Munguira, A.; Sánchez Lavega, A.; Lemmon, M. T.; Gómez, F.; Polkko, J.; Mandon, Lucía; Arruego, I.; Ramos, M.; Conrad, Pamela G.; Newman, C. E.; De la Torre Juarez, M.; Jordan, Francisco; Tamppari, L. K.; Mcconnochie, T. H.; Harri, Ari-Matti; Genzer, M.; Hieta, M.; Zorzano, María Paz; Siegler, M.; Prieto Ballesteros, O.; Molina, A.; Rodríguez Manfredi, J. A.; Apéstigue, Víctor; Comunidad de Madrid; Universities Space Research Association (USRA); Agencia Estatal de Investigación (AEI); Gobierno Vasco; Instituto Nacional de Técnica Aeroespacial (INTA); Centre National D'Etudes Spatiales (CNES); National Aeronautics and Space Administration (NASA); Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The Mars Environmental Dynamics Analyzer (MEDA) on board Perseverance includes first-of-its-kind sensors measuring the incident and reflected solar flux, the downwelling atmospheric IR flux, and the upwelling IR flux emitted by the surface. We use these measurements for the first 350 sols of the Mars 2020 mission (Ls ∼ 6°–174° in Martian Year 36) to determine the surface radiative budget on Mars and to calculate the broadband albedo (0.3–3 μm) as a function of the illumination and viewing geometry. Together with MEDA measurements of ground temperature, we calculate the thermal inertia for homogeneous terrains without the need for numerical thermal models. We found that (a) the observed downwelling atmospheric IR flux is significantly lower than the model predictions. This is likely caused by the strong diurnal variation in aerosol opacity measured by MEDA, which is not accounted for by numerical models. (b) The albedo presents a marked non-Lambertian behavior, with lowest values near noon and highest values corresponding to low phase angles (i.e., Sun behind the observer). (c) Thermal inertia values ranged between 180 (sand dune) and 605 (bedrock-dominated material) SI units. (d) Averages of albedo and thermal inertia (spatial resolution of ∼3–4 m2) along Perseverance's traverse are in very good agreement with collocated retrievals of thermal inertia from Thermal Emission Imaging System (spatial resolution of 100 m per pixel) and of bolometric albedo in the 0.25–2.9 μm range from (spatial resolution of ∼300 km2). The results presented here are important to validate model predictions and provide ground-truth to orbital measurements.
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Optical wireless links for intra-satellite communications: reflection models and hardware optimization
(Aerospace Research Central, 2010-05-23) Tamayo, R.; Alonso, José; Jiménez, J. J.; Arruego, I.; Guerrero, H.; Instituto Nacional de Técnica Aeroespacial (INTA)
The present work is a study on the propagation channel (physical layer) for wireless infrared communications in intra-satellite environments. Substituting cables and connectors with optical links inside a spaceborn platform offers many advantages and represents some technical challenges. We show analytical calculations, simulations, and experimental results for reflection models for aerospace materials, as well as wavelength division multiple access techniques for channel multiplexing. Improvements in the selection and optimization of emitter-detector pairs are also presented.
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Sensitivity evaluation method for aerospace digital systems with collaborative hardening
(Institute of Electrical and Electronics Engineers, 2011-06-15) Portela García, M.; García Valderas, M.; San Milán, E.; López Ongil, C.; Entrena, Luis; Rodríguez, Santiago; Martín-Ortega, Alberto; Martín-Ortega, Alberto; de Mingo Martín, José Ramón; Instituto Nacional de Técnica Aeroespacial (INTA)
Complexity of current digital systems and circuits involves new challenges in the field of hardening and measuring circuit's sensitivity under SEEs. In this work, a new solution for evaluating the SEU sensitivity of space systems based on using programmable logic devices is proposed. This solution is able to perform a deep analysis of fault effects in systems with hardware functionality distribution, taking into account the high complexity of the hardware nodes (complex programmable logic devices) and their collaborative hardening properties.
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In-orbit measurement of SET and DD fffects on optical wireless links for intra-satellite data transmission
(Institute of Electrical and Electronics Engineers, 2011-11-01) Arruego, I.; Martínez, J.; Guerrero, H.; Instituto Nacional de Técnica Aeroespacial (INTA)
In-orbit measurements of two experimental optical-wireless data links on board a polar LEO (Low Earth Orbit) spacecraft are presented. The effects of single event transients on the bit error rate, as well as those of displacement damage on the optoelectronic components being used, were measured. The results are consistent with those obtained from proton irradiations carried out in ground facilities.
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Proton monitor las dos torres: First Intercomparison of In-Orbit Results
(Institute of Electrical and Electronics Engineers, 2012-03-09) Jiménez, J. J.; Oter, J. M.; Hernando, C.; Ibarmia, S.; Hajdas, W.; Sanchez Péramo, J.; Álvarez, Maite; Arruego, I.; Guerrero, H.; Apéstigue, Víctor; Instituto Nacional de Técnica Aeroespacial (INTA)
A new proton monitor on board NANOSAT-1B-Las Dos Torres (translated: The Two Towers)-and its preliminary results after two years in orbit and its intercomparison to a RadFET and to trapped proton models are presented. This satellite was fully developed by INTA (National Institute of Aerospace Technology, Spain) and was launched on July 29, 2009. The instrument includes two stacks of radiation-sensing elements: the "dark" and "light" towers. The displacement damage was measured, both through the increase of a photodiode dark current ("dark tower") and the decrease of the photocurrent signal in a photodiode optically linked to light emitting diodes ("light tower"). The instrument was also designed to monitor the ionization current of the photodiodes and the variations in the proton flux in the South Atlantic Anomaly.
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Dosimeter for The Two Towers in SEOSAT-INGENIO Based on the TMP36 Temperature Sensor
(Institute of Electrical and Electronics Engineers, 2013-05-14) González Guerrero, M.; Jiménez, J. J.; Hernando, Carlos; Álvarez, Maite; Guerrero, H.; Instituto Nacional de Técnica Aeroespacial (INTA)
A dosimeter for space applications is presented. It is based on the ionization damage affecting the TMP36 sensors when they are exposed to external radiation, which produces an increase of their output voltages. This work explains the configuration, sensing mechanism and working modes of this device and reports the results obtained in a gamma radiation test carried out in March 2012. The test results allow us to select the mode of operation that provides the highest response to the TID, as well as the most sensitive devices. The highest sensitivity is above 100 μV/rad. This dosimeter is part of The Two Towers radiation monitor that will fly on board of the SEOSAT-INGENIO satellite.
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Measurement of dust optical depth using the solar irradiance sensor (SIS) onboard the ExoMars 2016 EDM
(Elsevier, 2017-01-20) Toledo, D.; Arruego, I.; Jiménez, J. J.; Gómez, L.; Yela González, M.; Rannou, P.; Pommereau, J. P.; Apéstigue, Víctor; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Economía y Competitividad (MINECO)
"The solar irradiance sensor (SIS) was included in the DREAMS package onboard the ExoMars 2016 Entry Descent and Landing Demonstrator Module, and has been selected in the METED meteorological station onboard the ExoMars 2020 Lander. This instrument is designed to measure at different time intervals the scattered flux or the sum of direct flux and scattered flux in UVA (315-400 nm) and NIR (700-1100 nm) bands. For SIS'16, these measurements are performed by a total of 3 sensors per band placed at the faces of a truncated tetrahedron with face inclination angles of 60. The principal goal of SIS'16 design is to perform measurements of the dust opacity in UVA and NIR wavelengths ranges, crucial parameters in the understanding of the Martian dust cycle. The retrieval procedure is based on the use of radiative transfer simulations to reproduce SIS observations acquired during daytime as a function of dust opacity. Based on different sensitivity analysis, the retrieval procedure also requires to include as free parameters (1) the, dust effective radius; (2) the dust effective variance; and (3) the imaginary part of the refractive index of dust particles in UVA band. We found that the imaginary part of the refractive index of dust particles does not have a big impact on NIR signal, and hence we can kept constant this parameter in the retrieval of dust opacity at this channel. In addition to dust opacity measurements, this instrument is also capable to detect and characterize clouds by looking at the time variation of the color index (CI), defined as the ratio between the observations in NIR and UVA channels, during daytime or twilight. By simulating CI signals with a radiative transfer model, the cloud opacity and cloud altitude (only during twilight) can be retrieved. Here the different retrieval procedures that are used to analyze SIS measurements, as well as the results obtained in different sensitivity analysis, are presented and discussed."
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The DREAMS experiment flown on the ExoMars 2016 mission for the study of Martian environment during the dust storm season
(Elsevier, 2018-02-01) Bettanini, C.; Esposito, F.; Debei, S.; Molfese, C.; Colombatti, G.; Aboudan, A.; Brucato, J. R.; Cortecchia, F.; Di Achille, G.; Guizzo, G. P.; Friso, Enrico; Ferri, F.; Marty, Laurent; Mennella, V.; Molinaro, R.; Schipani, P.; Silvestro, S.; Mugnuolo, R.; Pirrotta, S.; Marchetti, Edoardo; Ari-Matti, H.; Montmessin, F.; Wilson, Colin; Arruego, I.; Abbaki. S.; Bellucci, G.; Berthelier, J. J.; Calcutt, S.; Forget, F.; Genzer, M.; Gilbert, Pierre; Haukka, H.; Jiménez, Juan J.; Jiménez, Salvador; Josset, J. L.; Karatekin, Özgür; Landis, G.; Lorenz, Ralph; Martínez Oter, J.; Möhlmann, D.; Moirin, D.; Palomba, E.; Patel, M.; Pommereau, J. P.; Popa, C. I.; Rafkin, S.; Rannou, P.; Rennó, N. O.; Schmidt, W.; Simoes, F.; Spiga, A.; Valero, F.; Vázquez, L.; Apéstigue, Víctor; Agenzia Spaziale Italiana (ASI); Istituto Nazionale di Astrofisica (INAF)
"The DREAMS (Dust characterization, Risk assessment and Environment Analyser on the Martian Surface) instrument on Schiaparelli lander of ExoMars 2016 mission was an autonomous meteorological station designed to completely characterize the Martian atmosphere on surface, acquiring data not only on temperature, pressure, humidity, wind speed and its direction, but also on solar irradiance, dust opacity and atmospheric electrification; this comprehensive set of parameters would assist the quantification of risks and hazards for future manned exploration missions mainly related to the presence of airborne dust. Schiaparelli landing on Mars was in fact scheduled during the foreseen dust storm season (October 2016 in Meridiani Planum) allowing DREAMS to directly measure the characteristics of such extremely harsh environment. DREAMS instrument’s architecture was based on a modular design developing custom boards for analog and digital channel conditioning, power distribution, on board data handling and communication with the lander. The boards, connected through a common backbone, were hosted in a central electronic unit assembly and connected to the external sensors with dedicated harness. Designed with very limited mass and an optimized energy consumption, DREAMS was successfully tested to operate autonomously, relying on its own power supply, for at least two Martian days (sols) after landing on the planet. A total of three flight models were fully qualified before launch through an extensive test campaign comprising electrical and functional testing, EMC verification and mechanical and thermal vacuum cycling; furthermore following the requirements for planetary protection, contamination control activities and assay sampling were conducted before model delivery for final integration on spacecraft. During the six months cruise to Mars following the successful launch of ExoMars on 14th March 2016, periodic check outs were conducted to verify instrument health check and update mission timelines for operation. Elaboration of housekeeping data showed that the behaviour of the whole instrument was nominal during the whole cruise. Unfortunately DREAMS was not able to operate on the surface of Mars, due to the known guidance anomaly during the descent that caused Schiaparelli to crash at landing. The adverse sequence of events at 4 km altitude anyway triggered the transition of the lander in surface operative mode, commanding switch on the DREAMS instrument, which was therefore able to correctly power on and send back housekeeping data. This proved the nominal performance of all DREAMS hardware before touchdown demonstrating the highest TRL of the unit for future missions. The spare models of DREAMS are currently in use at university premises for the development of autonomous units to be used in cubesat mission and in probes for stratospheric balloons launches in collaboration with Italian Space Agency."
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Calibration OGSEs for multichannel radiometers for Mars atmosphere studies
(Springer Link, 2018-02-01) Jiménez Martín, Juan José; Álvarez, F. J.; González Guerrero, M.; Martín, I.; Fernán, A. A.; Arruego, I.; Apéstigue, Víctor; Fernández Marín, Juan Manuel; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Economía y Competitividad (MINECO)
This work describes several Optical Ground Support Equipment (OGSEs) developed by INTA (Spanish Institute of Aerospace Technology—Instituto Nacional de Técnica Aeroespacial) for the calibration and characterization of their self-manufactured multichannel radiometers (solar irradiance sensors—SIS) developed for working on the surface of Mars and studying the atmosphere of that planet. Nowadays, INTA is developing two SIS for the ESA ExoMars 2020 and for the JPL/NASA Mars 2020 missions. These calibration OGSEs have been improved since the first model in 2011 developed for Mars MetNet Precursor mission. This work describes the currently used OGSE. Calibration tests provide an objective evidence of the SIS performance, allowing the conversion of the electrical sensor output into accurate physical measurements (irradiance) with uncertainty bounds. Calibration results of the SIS on board of the Dust characterisation, Risk assessment, and Environment Analyzer on the Martian Surface (DREAMS) on board the ExoMars 2016 Schiaparelli module (EDM—entry and descent module) are also presented, as well as their error propagation. Theoretical precision and accuracy of the instrument are determined by these results. Two types of OGSE are used as a function of the pursued aim: calibration OGSEs and Optical Fast Verification (OFV) GSE. Calibration OGSEs consist of three setups which characterize with the highest possible accuracy, the responsivity, the angular response and the thermal behavior; OFV OGSE verify that the performance of the sensor is close to nominal after every environmental and qualification test. Results show that the accuracy of the calibrated sensors is a function of the accuracy of the optical detectors and of the light conditions. For normal direct incidence and diffuse light, the accuracy is in the same order of uncertainty as that of the reference cell used for fixing the irradiance, which is about 1%.

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