An example of Space Engineering Education in Spain: a master in space based on Project-Based Learning (PBL)

This work describes the successful education experience for five years of space engineering education at the Universidad Politécnica de Madrid (UPM), Madrid, Spain. The MSc. in Space Systems (MUSE, Máster Universitario en Sistemas Espaciales) is a 2-year and 120-ECTS (European Credit Transfer and Accumulation System) master program organized by the Microgravity Institute ‘Ignacio Da Riva’ (IDR/UPM), a research institute of UPM with extensive experience in the space sector. The teaching methodology is oriented to Project Based Learning (PBL), taking advantage of the IDR/UPM Institute experience. The main purposes are to share the IDR/UPM knowledge with the students and promote their collaboration with several space scientific institutions, both national and international. In the present work, the most relevant characteristics of this master program are described, highlighting the importance of the student’s participation in actual missions. In addition, to offer practical cases in all aspects of satellite development, the IDR/UPM decided to create its own satellite development program, the UPMSats. The latest, the UPMSat-2, is an educational, scientific, and in-orbit technological demonstration microsatellite (50 kg-class) that was launched in September 2020 on-board a Vega launcher (VV-16 flight). MUSE students have participated in all phases of the mission, from design to integration, calibration, and testing, and (at present) in-orbit operation. The construction of a microsatellite, although it exceeds in time the academic duration of the master, has proven to be a very interesting and versatile tool for PBL education, since it provides practical cases at all levels of development. Furthermore, the continuity of the project encourages graduated students to continue their education with a Ph.D. and the collaboration of master and doctoral students. These reasons have made MUSE one of the most successful academic programs in space systems engineering in Spain, with high employment rates in the most prestigious space engineering institution

Correlation of spacecraft termal mathematical models to reference data

Model-to-test correlation is a frequent problem in spacecraft-thermal control design. The goal of correlation 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. This way the uncertainty of the mathematical model is reduced. 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 undoubtedly facilitate this work. The correlation process can therefore be considered as the selection of the model parameters that minimize the error of the model results with regard to the reference data. In this doctoral dissertation, a simple method (GIPI) is presented. The method is 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, consisting of a simple 4-node model, and the other one a complex model, the TMM of the optical unit of PHI, one of the remote sensing instruments of the ESA mission Solar Orbiter. The method has given satisfactory reslts in both cases. The convergence of the method has been studied and compared with several methods and the time required by this method (GIPI) subtantially outperforms the other methods

Estudio de viabilidad del diseño térmico de la unidad electrónica del instrumento PHI a bordo del satélite Solar Orbiter

El instrumento PHI a bordo del Solar Orbiter [1] es un telescopio que está compuesto por una unidad óptica y otra electrónica. La unidad electrónica está encargada de controlar, adquirir y procesar los datos provenientes de la unidad óptica así como de proporcionar la energía suficiente para su funcionamiento. Debido a los ambientes térmicos extremos en un entorno de vacío que va a encontrar la unidad a lo largo de la misión, con una órbita en la que la distancia al sol varía desde 0,28 hasta 1,5 UA, a los estrechos márgenes operativos de algunos componentes y a la cantidad de potencia disipada en la unidad, el diseño térmico [2] de la misma ha sido optimizado para mantener la electrónica en niveles de temperatura adecuados para su funcionamiento [3]. La unidad electrónica apenas ocupa un volumen de 220 x 220 x 170 mm, tiene que evacuar la potencia principalmente por conducción a través de su base y por radiación al interior del satélite. El diseño térmico ha sido realizado mediante un modelo matemático utilizando el software ESATANTMS [4] y se ha verificado mediante ensayos en una cámara de vacío.Este trabajo ha sido financiado por el Ministerio de Ciencia e Innovación y el Ministerio de Economía y competitividad, ProyectosAYA2009-14105-C06-02, AYA2011-29833-C06-02 yAYA2012-39636- C06-04

On the Variation of Cup Anemometer Performance Due to Changes in the Air Density

In the present paper, the effect of air density variations on cup anemometer performance is analyzed. The effect on the sensor’s performance is mainly due to the difference between the altitude at which the cup anemometer is working and the altitude at which this instrument was calibrated. Data from the available literature are thoroughly analyzed, focusing on explaining the coupled effect of the air temperature on both the rotor’s friction torque and the air density (that is, related to the aerodynamic torque on the rotor). As a result, the effect of air density variation at constant temperature (that is, leaving aside any variation of friction forces at the anemometer rotor shaft) on the sensor transfer function (i.e., on the calibration constants) is evaluated. The analysis carried out revealed a trend change in the variation with air density of the transfer function of the cup anemometer. For densities greater than 0.65, the calibration constants of the instrument have a variation with density that must necessarily change suddenly as the start-up speed, represented by the calibration constant B, becomes zero around this value of air density. To highlight the relevance of the present research, some estimations of the effect of wind speed measurement errors associated with air density changes on the Annual Energy Production (AEP) of wind turbines are included. A 1.5% decrease in the AEP forecast at air density corresponding to 2917 m above sea level is estimated for 3000–4500 kW wind turbines

Thermal Analysis of SUSI-O on SUNRISE III

Alejandro Fernandez-Soler, IDR/UPM, SpainFernandez-Rico, Max Planck Institute for Solar System, GermanyAlex Feller, Max Planck Institute for Solar System, GermanyIgnacio Torralbo-Gimeno, IDR/UPM, SpainIsabel Perez-Grande, IDR/UPM, SpainICES109: Thermal Control of High Altitude Balloon SystemsThe proceedings for the 2020 International Conference on Environmental Systems were published from July 31, 2020. The technical papers were not presented in person due to the inability to hold the event as scheduled in Lisbon, Portugal because of the COVID-19 global pandemic.Sunrise UV Spectro-Polarimeter and Imager Optics Unit (SUSI-O) is a solar optical spectropolarimeter designed to explore the 300-430 nm band, which is poorly accessible from the ground. With that purpose, SUSI-O will be included in the third flight of the balloon-borne SUNRISE observatory. SUNRISE observatory is designed to operate in the stratosphere (around 37 km), where, from the thermal point of view, the environmental conditions are very close to the ones found at space although some particularities have to be taken into account. To fulfill the scientific requirements, the Thermal Control System (TCS) of the instrument plays an important role. The paper presents an overview of the SUSI-O thermal design and the analyses carried out in order to verify thermal requirements and guarantee thermal stability during the scientific observations. For the float operational phase, two steady-state cases (Hot and Cold) have been considered whereas a transient analysis might be needed for the ascent phase. The thermal hardware necessary to verify thermal requirements during the ascent and float phases is presented. It includes both, active and passive elements, including heaters, and radiators, single layer insulation (SLI) blankets, Styrofoam insulation, thermal straps and thermal tapes, respectively

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

Improvement in Radiative Exchange Factor Calculations Using New GPU Dedicated Hardware

Daniel Navajas Ortega, Instituto Universitario de Microgravedad(IDR) / Universidad Politécnica de Madrid(UPM), SpainJavier Piqueras Carreño, Instituto Universitario de Microgravedad(IDR) / Universidad Politécnica de Madrid(UPM), SpainIgnacio Torralbo Gimeno, Instituto Universitario de Microgravedad(IDR) / Universidad Politécnica de Madrid(UPM), SpainIsabel Pérez-Grande, Instituto Universitario de Microgravedad(IDR) / Universidad Politécnica de Madrid(UPM), SpainICES207: Thermal and Environmental Control Engineering Analysis and SoftwareDavid González Bárcena, Instituto Universitario de Microgravedad(IDR) / Universidad Politécnica de Madrid(UPM), SpainThe 52nd International Conference on Environmental Systems was held in Calgary, Canada, on 16 July 2023 through 20 July 2023.The aim of this work is to test the applicability of new GPUs, with dedicated hardware to accelerate raytracing computations, for calculating radiative exchange factors of thermal models. Radiative exchange factors (REFs) are used to model the net exchange of thermal energy by radiation between two surfaces. While there are analytical solutions for simple configurations, for general thermal models most REFs are calculated numerically. Montecarlo raytracing algorithms are typically used to this end. Raytracing algorithms simulate the radiation thermal energy transportation phenomena by emitting, tracing, and bouncing energy particles (usually called rays) between the different surfaces that make up the thermal model. The thermo-optical properties of the surfaces determine the interaction between the rays and the model. Although raytracing algorithms are conceptually simple, to obtain accurate solutions a large number of rays need to be traced, which is a process extremely expensive computationally. However, because each ray can be considered independent, the simulation is also easily parallelizable, and therefore very suitable to be computed by a GPU, especially the new ones with built-in raytracing capabilities. To do so, a multi-platform software has been developed. The software is able to handle general geometry and better exploit the computing capabilities of the GPU by using triangular meshes internally. The conversion between the internal representation of the geometry and the geometrical thermal model is handled automatically. The result is a code that can calculate all REFs of a complex thermal model much faster than commercially available software where only the CPU is used. The software has been tested with the thermal model of the PHI instrument of the ESA Solar Orbiter mission. In the same machine, with single GPU, and using 10E6 rays per surface, the developed code can calculate the REFs around 2 to 3 orders of magnitude faster than ESATAN-TMS

Thermal Analysis of the Solar Orbiter PHI Electronics Unit

This work presents the thermal design of the electronics unit of the instrument PHI, onboard the ESA mission Solar Orbiter. The thermal design procedure, along with the problems encountered during this design phase, and the solutions found to fix them are described, proving in this way the thermal feasibility and robustness of the unit. Its final thermal behaviour, obtained from thermal analyses correlated with data from thermal tests performed in a vacuum environment, is presented

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