Diseño del módulo de cálculo de potencia eléctrica para su aplicación en una CDF = Design of the power subsystem of a concurrent design facility (CFD) for satellite projects

El desarrollo del presente trabajo sigue, tanto una línea cronológica de las tareas realizadas, como una lógica, en la que se parte de un conocimiento mínimo de los sistemas espaciales hasta llegar al diseño completo de un Módulo de Cálculo de Potencia Eléctrica de un satélite para su aplicación en una instalación de diseño concurrente o CDF

SPGCam: A specifically tailored camera for solar observations

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Designing a new astronomical instrument typically challenges the available cameras on the market. In many cases, no camera can fulfill the requirements of the instrument in terms of photon budget, speed, and even interfaces with the rest of the instrument. In this situation, the only options are to either downgrade the performance of the instrument or design new cameras from scratch, provided it is possible to identify a compliant detector. The latter is the case of the SPGCams, the cameras developed to be used with the Tunable Magnetograph (TuMag) and the Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) for the Sunrise iii mission. SPGCams have been designed, developed, and built entirely in-house by the Solar Physics Group (SPG) at the Instituto de Astrofísica de Andalucía (IAA-CSIC). We report here on the scientific rationale and system engineering requirements set by the two instruments that drove the development, as well as on the technical details and trade-offs used to fulfill the specifications. The cameras were fully verified before the flight, and results from the assembly and verification campaign are presented as well. SPGCams share the design, although some parametric features differentiate the visible cameras (for TuMag) and the IR ones (for SCIP). Even though they were specifically developed for the Sunrise iii mission, the robust and careful design makes them suitable for different applications in other astronomical instruments. © 2023 Orozco Suárez, Álvarez García, López Jiménez, Balaguer Jiménez, Hernández Expósito, Labrousse, Bailén, Bustamante Díaz, Bailón Martínez, Aparicio del Moral, Morales Fernández, Sánchez Gómez, Tobaruela Abarca, Moreno Mantas, Ramos Más, Pérez Grande, Piqueras Carreño, Katsukawa, Kubo, Kawabata, Oba, Rodríguez Valido, Magdaleno Castelló and Del Toro Iniesta.This work was funded by the Spanish MCIN/AEI, under projects RTI 2018-096886-B-C5, PID 2021-125325OB-C5, and PCI 2022-135009-2, and co-funded by European FEDER funds, “A way of making Europe,” under grants CEX 2021-001131-S and 10.13039/501100011033.Peer reviewe

Improvement of lumped thermal models: Calculation of accurate linear conductances and transient correlation to reference data

Thermal mathematical models are the main tool an engineer has to optimize the thermal design of a spacecraft. The better the physical system is mathematically approximated, the better the design solution will be. Hence the importance of developing new techniques to improve the modelling process. In this work, two different methods to improve thermal models based on the lumped parameters formulation are presented. The first one, called Conductance Matrix Fitting (CMF) method, is a new method intended to calculate accurate linear conductances. Linear conductances connect different nodes of a thermal model in order to represent conduction heat transfer. The method is based on the generation of a detailed lumped thermal model of the component. After setting-up the detailed model, it is condensed to create a reduced model. The unknown conductances of the reduced model are automatically calculated by correlating the temperature and heat flow of the reduced model with the results of the detailed model. The conductances of the component determined in this way can be used for modelling the complete device. The second one addresses the transient correlation of thermal models to reference data. The correlation is a common problem in the spacecraft thermal control field. The goal is to find the set of parameters of the model that best approach the solution to a given reference data. Here, the problem is formulated as a non-linear least squares minimization and different algorithms are suggested and compared. Because in a typical correlation problem the parameters to be optimized are near the solution, local optimization is expected work well. Thus, iterative minimization algorithms based on quasi-Newton steps are those with the faster convergence. However, these algorithms need the Jacobian matrix at each iteration, which is computationally very expensive. To overcome this limitation, an efficient way to obtain the Jacobian matrix is also presented. Both methods have been tested with thermal models of real hardware, such as the PHI instrument of the ESA Solar Orbiter mission or some cameras of the Sunrise III mission

UPMSat-2 ACDS magnetic sensors test campaign

The present paper summarizes the testing work carried out in relation to the UPMSat-2 Attitude, Control and Determination Subsystem (ADCS) sensors. The ACDS of this satellite is based on the magnetic interaction with the Earth magnetic field, thus the selected sensors have been magnetometers. This test campaign was carried out in order to check the performance and accuracy of the magnetometers (acceptance tests) and to analyse its effect on the characteristic times of the satellite’s stabilization process once its normal attitude has been perturbed (integration tests). Since the adequate calibration instruments were not available in the institute, for the acceptance tests a simplified method was designed and performed. The proposed methodology allows auto-calibrating the magnetometers, using the Earth magnetic field as reference and without a comparing with calibrated magnetometers. For the integration tests, the estimated errors were introduced in the simulator of the mission in order to analyse its effect on the stabilization time, once the satellite’s attitude is perturbed. The results of the simulations indicate a correct performance of the magnetometers, as the convergence of the satellite attitude to the target one was reached within a reasonable period

Correlation of spacecraft thermal mathematical models to reference data

Model-to-test correlation is a frequent problem in spacecraft-thermal control design. The idea is to determine the values of the parameters of the thermal mathematical model (TMM) that allows reaching a good ?t between the TMM results and test data, in order to reduce the uncertainty of the mathematical model. Quite often, this task is performed manually, mainly because a good engineering knowledge and experience is needed to reach a successful compromise, but the use of a mathematical tool could facilitate this work. The correlation process can be considered as the minimization of the error of the model results with regard to the reference data. In this paper, a simple method is presented suitable to solve the TMM-to-test correlation problem, using Jacobian matrix formulation and Moore-Penrose pseudo-inverse, generalized to include several load cases. Aside, in simple cases, this method also allows for analytical solutions to be obtained, which helps to analyze some problems that appear when the Jacobian matrix is singular. To show the implementation of the method, two problems have been considered, one more academic, and the other one the TMM of an electronic box of PHI instrument of ESA Solar Orbiter mission, to be ?own in 2019. The use of singular value decomposition of the Jacobian matrix to analyze and reduce these models is also shown. The error in parameter space is used to assess the quality of the correlation results in both models

A new method to correlate Thermal Mathematical Models of space instruments and payloads

The correlation of the Thermal Mathematical Models is often performed manually, and the results obtained in this way are generally not the optimum and could be improved with other strategies. A method of correlation is presented for for steady-state cases. The method is based on a Jacobian matrix formulation and a Moore-Penrose pseudo-inversion. The formulation allows the correlation of a model with several load cases, as it is the usual case in space projects. As an example, it has been applied to the thermal mathematical model of the Optics Unit of the instrument PHI of the ESA Solar Orbiter mission

Preliminary thermal design of SCIP instrument

The SUNRISE Chromospheric Infrared spectroPolarimeter Optics Unit (SCIP-O) is one of the instruments on-board the SUNRISE-3 balloon borne telescope, and it is being developed by NAOJ. The SCIP-O is located inside the Post Focus Instrumentation (PFI) of SUNRISE-3 and it consists of an optical bench mounted in the PFI by means of three titanium mechanical interfaces. These interfaces provide low thermal coupling with the PFI structure. The bench is covered above by an aluminium case and below by a Single-layer insulation (SLI). Additionally, the top cover area, which is not intended as a radiator, is insulated with polystyrene foam. Therefore, the unit is conductively and radiatively insulated from its environment. On the bench the optical elements, including three cameras, are located. To reduce stray light, interior metallic surfaces are black anodized. The unit is thermally designed to reject the heat, originated due to electronic components dissipation and coming from the PFI radiative and conductive environment, to space through dedicated radiators located on the top of cover of the unit. Three different radiators are considered, each one approximately centred above a camera. Each radiator is conductively connected to each camera cold finger by means of a copper thermal strap. The CMOS sensor of each camera is cooled down through direct contact with the camera cold finger. In order to guarantee the thermal stability in some critical parts, stabilization heaters based on set-points are placed. Thermal stability of the sensor is achieved with a dedicated heater located in the cold finger of each camera. Temperature and thermal stability requirements of the optical bench are achieved by a series of heaters situated on the bottom surface of the bench. The location of the optical bench heaters is under assessment to minimize temperature spatial gradients

SPGCam: A specifically tailored camera for solar observations

Designing a new astronomical instrument typically challenges the available cameras on the market. In many cases, no camera can fulfill the requirements of the instrument in terms of photon budget, speed, and even interfaces with the rest of the instrument. In this situation, the only options are to either downgrade the performance of the instrument or design new cameras from scratch, provided it is possible to identify a compliant detector. The latter is the case of the SPGCams, the cameras developed to be used with the Tunable Magnetograph (TuMag) and the Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) for the Sunrise iii mission. SPGCams have been designed, developed, and built entirely in-house by the Solar Physics Group (SPG) at the Instituto de Astrofísica de Andalucía (IAA-CSIC). We report here on the scientific rationale and system engineering requirements set by the two instruments that drove the development, as well as on the technical details and trade-offs used to fulfill the specifications. The cameras were fully verified before the flight, and results from the assembly and verification campaign are presented as well. SPGCams share the design, although some parametric features differentiate the visible cameras (for TuMag) and the IR ones (for SCIP). Even though they were specifically developed for the Sunrise iii mission, the robust and careful design makes them suitable for different applications in other astronomical instruments

Influencia de la historia de tabaquismo en la evolución de la hospitalización en pacientes COVID-19 positivos: datos del registro SEMI-COVID-19.

Smoking can play a key role in SARS-CoV-2 infection and in the course of the disease. Previous studies have conflicting or inconclusive results on the prevalence of smoking and the severity of the coronavirus disease (COVID-19). Observational, multicenter, retrospective cohort study of 14,260 patients admitted for COVID-19 in Spanish hospitals between February and September 2020. Their clinical characteristics were recorded and the patients were classified into a smoking group (active or former smokers) or a non-smoking group (never smokers). The patients were followed up to one month after discharge. Differences between groups were analyzed. A multivariate logistic regression and Kapplan Meier curves analyzed the relationship between smoking and in-hospital mortality. The median age was 68.6 (55.8-79.1) years, with 57.7% of males. Smoking patients were older (69.9 [59.6-78.0 years]), more frequently male (80.3%) and with higher Charlson index (4 [2-6]) than non-smoking patients. Smoking patients presented a worse evolution, with a higher rate of admission to the intensive care unit (ICU) (10.4 vs 8.1%), higher in-hospital mortality (22.5 vs. 16.4%) and readmission at one month (5.8 vs. 4.0%) than in non-smoking patients. After multivariate analysis, smoking remained associated with these events. Active or past smoking is an independent predictor of poor prognosis in patients with COVID-19. It is associated with higher ICU admissions and in-hospital mortality