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The Bolund experiment has been reproduced in a neutral boundary layer wind tunnel (WT) at scale 1:115 for two Reynolds numbers. All the results have been obtained for an incoming flow from the 270° wind direction (transect B in the Bolund experiment jargon). Vertical scans of the velocity field are obtained using non-time resolved two components particle image velocimetry. Time-resolved velocity time series with a three component hot-wire probe have been also measured for transects at 2 and 5 m height and in the vertical transects at met masts M6, M3 and M8 locations. Special attention has been devoted to the detailed characterization of the inflow in order to reduce uncertainties in future comparisons with other physical and numerical simulations. Emphasis is placed on the analysis of spectral functions of the undisturbed flow and those of the flow above the island. The result's reproducibility and trustworthiness have been addressed through redundancy measurements using particle image velocimetry, two and three components hot-wire anemometry. The bias in the prediction of the mean speed is similar to the one reported during the Bolund experiment by the physical modellers. However, certain reduction of the bias in the estimation of the turbulent kinetic energy is achieved. The WT results of spectra and cosprectra have revealed a behaviour similar to the full-scale measurements in some relevant locations, showing that WT modelling can contribute to provide valid information about these important structural loading factors.

In a search for improvements in their academic plans, most universities are focused today in the development and use of innovative educational programs. Within the different possible innovative educational techniques, Research-Based Learning (RBL) is focused on the generation of didactic experiences based on the scientific method (question formulation, search for answers and solutions, resolution of problems and analysis of results). This method allows engineers and researchers to face new problems through the search of innovation and novel solutions to the problems, out of the common standards. The inclusion of the scientific method within the academic plan of the master’s degree in space systems (MUSE) of Universidad Politecnica de Madrid (UPM) is carried out through the definition of study cases. These study cases and the RBL employed methodology supports the theoretical contents of the other subjects included in the MUSE’s academic plan. In the Microgravity Institute ‘Ignacio Da...

Pressure measurements on the surface of a 1:230 scale model of Bolund Island are presented. The model is smooth and no boundary layer generation has been considered since the experiment is designed as the simplest possible reference case. Measurement have been taken for a range of Reynolds numbers based on the average undisturbed wind speed U∞ and the maximum height of the island, h [1.7×104, 8.5×104], and for a range of wind directions. Four minutes time series of pressure in more than 400 points have been acquired and analysed to obtain the spatial distribution of both the time average and the variance of the pressure signal. The horizontal extension of the detachment bubble for the different Reynolds numbers and wind directions is identified by isobars and curves of constant value of pressure variance. The applicability of this technique for evaluating the horizontal topology of high turbulence regions associated to detachment bubbles after escarpments in potential wind farm site...

We present experimental spatial distributions of turbulence intensity components over a 1:115 scale model of the Bolund hill. Our measurements are determined in a boundary layer wind tunnel (WT) without stratification. Our results are compared with full scale (FS) ones. The FS results are obtained from the analysis of the database provided by RISO-DTU after the Bolund experiment. This experiment was conducted by them during a 3-month period in the winter of 2007-2008 [1]. Three component time resolved hotwire anemometry (3CHW) and two component particle image velocimetry (PIV) are used in our experiment.

The UPMSat-2 is the second satellite designed and developed by the IDR/UPM as part of the UPM-Sats program. It is a scientific micro satellite of 45 kg whose aim is providing the required know-how to design, develop, manufacture, integrate, test and finally operate a complete space system. Furthermore, it serves as on orbit demonstration platform for space technologies. The UPMSat-2 launch is scheduled for summer 2019. The work here exposed includes the whole testing in thermal vacuum chamber, including the different challenges found with the aim of sharing the know-how gained.

Today, project-based learning is a well-known methodology in engineering education. In the IDR/UPM Institute of Universidad Politecnica de Madrid (UPM), different lines of research have been developed to involve students into projects related to aerodynamics (both theoretical and experimental), fluid dynamics on low gravity, and space science (heat transfer).Although these lines of research were initially related to the Ph.D. programs integrated within the academic plan of the university, the increasing interest among the bachelor and master students on research and projects linked to the most advanced engineering techniques, prompted the IDR/UPM academic staff to offer some specific projects to these students as their final degree thesis. In the present work, the UPMSat-2 satellite project is analyzed as an academic tool to involve different groups of students into a big project,encouraging them not only to develop specific skills in relation to a single subsystem of the satellite,...

A methodology to efficiently simulate wind tunnel tests of several airfoils with OpenFOAM has been developed in this work. This methodology bridges OpenFOAM capabilities with Matlab postprocessing to analyse efficiently the performance of wind turbine airfoils at any angle of attack. This technique has been developed to reduce the cost, in terms of time and resources, of wind tunnel campaigns on wind turbine blade airfoils. Different turbulence models were used to study the behaviour of the airfoils near stall. Wind turbine airfoils need to be characterized for all possible angles of attack, in order to reproduce the real aerodynamic patterns during operation. Unfortunately, this situation is translated into a huge demand of wind tunnel testing resources, airfoil manufacturing and data post-processing. The high costs in terms of experimental measurements have encouraged many researches to elaborate airfoil catalogues by performing CFD simulations.Results are compared with a testing ...

This paper presents the development of the UPMSat-2 sun sensor, from the design to on-orbit operation. It also includes the testing of the instrument, one of the most important tasks that needs to be performed to operate a sensor with precision. The UPMSat-2 solar sensor has been designed, tested, and manufactured at the Universidad Politécnica de Madrid (UPM) using 3D printing and COTS (photodiodes). The work described in this paper was carried out by students and teachers of the Master in Space Systems (Máster Universitario en Sistemas Espaciales—MUSE). The solar sensor is composed of six photodiodes that are divided into two sets; each set is held and oriented on the satellite by its corresponding support printed in Delrin. The paper describes the choice of components, the electrical diagram, and the manufacture of the supports. The methodology followed to obtain the response curve of each photodiode is simple and inexpensive, as it requires a limited number of instruments and to...

The design process of an Electrical Power Subsystem (EPS) for a space mission is a key factor in order to be successful. During last decades, components included in this subsystem have been progressively released from a more and more wide range of suppliers. This fact has allowed access to the space power technologies to an increased number of users, resulting in the arrival of COTS elements to the design and development of space power subsystems (specially in nanosats). In the present work, the development of a Li-Ion battery at IDR/UPM based on COTS elements for the UNION/Lian-He mission is described.

The influence of anemometer rotor shape parameters, such as the cups’ front area or their center rotation radius on the anemometer’s performance was analyzed. This analysis was based on calibrations performed on two different anemometers (one based on magnet system output signal, and the other one based on an opto-electronic system output signal), tested with 21 different rotors. The results were compared to the ones resulting from classical analytical models. The results clearly showed a linear dependency of both calibration constants, the slope and the offset, on the cups’ center rotation radius, the influence of the front area of the cups also being observed. The analytical model of Kondo et al. was proved to be accurate if it is based on precise data related to the aerodynamic behavior of a rotor’s cup.

In this paper, the experimental results of an unconventional joined-wing aircraft configuration are presented. The test model uses two different wings, forward and rear, both joined in tandem and forming diamond shapes both in plant and front views. The wings are joined in such a way that it is possible to change the rear wing dihedral angle values and the rear wing sweep angle values in 25 different positions that modify the relative distance and the relative height between the wings. To measure the system aerodynamic coefficients it is necessary to perform wind tunnel tests. The data presented corresponds to the lift, drag and induced drag aerodynamic coefficients, as well as the aerodynamic efficiency and the parameter for minimum required power, from the calculated values of the lift and drag time series measured by a 6-axis force and torque sensor. The results show the influence on the aerodynamic coefficients of the rear wing sweep and dihedral angles parameters. As a main res...

The UPMSat-2 micro-satellite was launched on September the 3rd 2020 at 01:51:10 UTC from Kourou spaceport in French Guyana. The VV16 Vega Flight has been the first low Earth orbit rideshare commercial flight with a total of 53 satellites (7 of them micro-satellites) to be released by the launch vehicle, arranged in the modular SSMS (Small Spacecraft Mission Service) dispenser. UPMSat-2 is an educational, scientific and in-orbit technological demonstration microsatellite project led by the IDR/UPM research institute from Universidad Politécnica de Madrid (UPM), Spain. This mission can be considered as a logical extension of the IDR/UPM Institute activities focused on designing small satellites to be used as educational platforms of first level. Thereby, UPMSat-2 (as well as its precursor, the UPMSat-1) has the main objective to give students the competences for designing, analyzing, manufacturing, integrating, testing and operating the platform. UPMSat-2 also includes a set of scient...

The Master in Space Systems (Máster Universitario en Sistemas Espaciales – MUSE) at UPM (Universidad Politécnica de Madrid) is an academic program organized at Instituto Universitario de Microgravedad “Ignacio Da Riva” (IDR/UPM) research institute. This is a 2-year Project Based Learning (PBL) master program which started in 2014. Since the first year of the MUSE, the students have participated actively in the development and construction of the UPMSat-2, an educational, scientific and in-orbit technological demonstration 50 kg-class microsatellite launched on September 2nd, 2020. Students from MUSE have participated in all phases of the mission, from the design of subsystems to in-orbit operation, and including integration, calibration, and testing. In the present work, the most relevant characteristics of this master program are described, the importance of the satellite’s design and development within the academic tasks being emphasized. Graduated MUSE students have a high employ...

In combination with magnetometers, solar sensors are one of the most used instruments for determining the attitude of small satellites. These devices use the photoelectric effect to produce an electrical current. This electrical current, or the voltage associated with the electrical circuit of the solar sensor, is measured in order to compute the angle of incident of the sun with the normal direction of the sensor. Then, together with the computed angles of other solar sensors on different faces of the satellite, the sun's direction in relation to a spacecraft can be calculated. Solar sensors are simple devices whose low-cost design based on photodiodes can be developed by students. During the design and fabrication process of a solar sensor, one of the most important tasks is the accurate estimation of the sensor response in the space radiative environment. It is possible to simulate the Sun’s radiation spectrum, but the equipment and facilities needed are costly for a universi...

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 al...

Key Science Questions to be Addressed • What are the physical processes shaping planetary atmospheres? • What are exoplanets made of? • How do planets and planetary systems form and evolve? Science Objectives (Chapter 2) Ariel Definition Study Report page 3 Foreword The concept of a mission devoted to atmospheric characterization of exoplanets through transit spectroscopy was first considered in Europe in 2007, shortly after the DARWIN proposal submitted to ESA for the first Cosmic Vision call for L-class missions was rejected because of the need for further scientific and technical developments. Following the decision, both ESA (EP-RAT panel report, October 2010) and the Exoplanetary Community (Blue Dot Team-Barcelona conference, September 2009) started a discussion to define a roadmap for exoplanetary research. Both groups concluded that an intermediate step was needed, both scientifically and technically, before the characterisation of Earth-like planets could be tackled, and recommended a transit spectroscopy mission as a first step to atmospheric characterisation. A short study was undertaken at ESTEC in the context of the ExoPlanet Roadmap Advisory Team mandate under the name ESM (Exoplanet Spectroscopy Mission). Following this study the Exoplanet Characterisation Observatory (EChO) was proposed and accepted for assessment phase study in the context of the ESA Cosmic Vision 2015-2025 programme M3 medium class mission opportunity. Although eventually not selected, the EChO study 1 allowed further development of the technical building blocks and the science case for an eventual transit spectroscopy mission. In response to the call for the next medium class opportunity, Cosmic Vision M4, a proposal was submitted in January 2015: the Atmospheric Remote-sensing InfraRed Large-survey (ARIEL). The mission was one of the three selected in June 2015 for study in a Phase 0/A, a competitive assessment phase 2. ARIEL was eventually selected as M4 in March 2018, and went into Phase B1, the definition study phase. The name of the mission has been changed to Ariel after selection. During Phase B1, the science case was studied in depth and consolidated under auspices of the Science Advisory Team, the bulk of the work being performed in a large number of science working groups in the Ariel Mission Consortium (AMC). The ESA Study Team and AMC reviewed the mission requirements, the technical design and analysis of the complete payload module (including telescope, instruments, guidance system and supporting infrastructure). The AMC developed an end-to-end performance simulator of the complete system. Two industrial contractors (Airbus Defence and Space, France and ThalesAlenia Space, France) reviewed the mission requirements, the technical design and analysis of the s/c and performed a programmatic analysis of the mission. Dedicated iterations were done in conjunction with both industrial and payload studies to harmonise the interfaces between the s/c and the payload, and to consolidate the payload accommodation. Recently the ESA Mission Adoption Review has successfully been concluded. This definition study report presents a summary of the very large body of work that has been undertaken on the Ariel mission over the 30-month period of the Ariel definition phase. As such, it represents the contributions of a large number of parties (ESA, industry, institutes and universities from 17 ESA member states, NASA CASE team), encompassing a very large number of people.

Key Science Questions to be Addressed • What are the physical processes shaping planetary atmospheres? • What are exoplanets made of? • How do planets and planetary systems form and evolve? Science Objectives (Chapter 2) Ariel Definition Study Report page 3 Foreword The concept of a mission devoted to atmospheric characterization of exoplanets through transit spectroscopy was first considered in Europe in 2007, shortly after the DARWIN proposal submitted to ESA for the first Cosmic Vision call for L-class missions was rejected because of the need for further scientific and technical developments. Following the decision, both ESA (EP-RAT panel report, October 2010) and the Exoplanetary Community (Blue Dot Team-Barcelona conference, September 2009) started a discussion to define a roadmap for exoplanetary research. Both groups concluded that an intermediate step was needed, both scientifically and technically, before the characterisation of Earth-like planets could be tackled, and recommended a transit spectroscopy mission as a first step to atmospheric characterisation. A short study was undertaken at ESTEC in the context of the ExoPlanet Roadmap Advisory Team mandate under the name ESM (Exoplanet Spectroscopy Mission). Following this study the Exoplanet Characterisation Observatory (EChO) was proposed and accepted for assessment phase study in the context of the ESA Cosmic Vision 2015-2025 programme M3 medium class mission opportunity. Although eventually not selected, the EChO study 1 allowed further development of the technical building blocks and the science case for an eventual transit spectroscopy mission. In response to the call for the next medium class opportunity, Cosmic Vision M4, a proposal was submitted in January 2015: the Atmospheric Remote-sensing InfraRed Large-survey (ARIEL). The mission was one of the three selected in June 2015 for study in a Phase 0/A, a competitive assessment phase 2. ARIEL was eventually selected as M4 in March 2018, and went into Phase B1, the definition study phase. The name of the mission has been changed to Ariel after selection. During Phase B1, the science case was studied in depth and consolidated under auspices of the Science Advisory Team, the bulk of the work being performed in a large number of science working groups in the Ariel Mission Consortium (AMC). The ESA Study Team and AMC reviewed the mission requirements, the technical design and analysis of the complete payload module (including telescope, instruments, guidance system and supporting infrastructure). The AMC developed an end-to-end performance simulator of the complete system. Two industrial contractors (Airbus Defence and Space, France and ThalesAlenia Space, France) reviewed the mission requirements, the technical design and analysis of the s/c and performed a programmatic analysis of the mission. Dedicated iterations were done in conjunction with both industrial and payload studies to harmonise the interfaces between the s/c and the payload, and to consolidate the payload accommodation. Recently the ESA Mission Adoption Review has successfully been concluded. This definition study report presents a summary of the very large body of work that has been undertaken on the Ariel mission over the 30-month period of the Ariel definition phase. As such, it represents the contributions of a large number of parties (ESA, industry, institutes and universities from 17 ESA member states, NASA CASE team), encompassing a very large number of people.