#### Simple mathematical approach to solar cell/panel behavior based on datasheet information

• Cubas Cano, Javier
new explicit mathematical expression is used to describe the behavior of a photovoltaic device (solar cell/panel), that is, its I-V curve, based on the characteristic points normally included in the manufacturers’ datasheets. This expression consists of two simple equations, one for voltage levels lower than the voltage at the maximum power point, V < Vmp, and the other one for voltage levels above this point, V > Vmp. The first equation is defined with two of the three characteristic points (short circuit and maximum power points), whereas the second one is defined with the current and voltage levels at maximum power point, the open circuit voltage, and a constant that can be adjusted based on: 1) the best fitting to the data within the bracket [Vmp, Voc], or 2) one point within this bracket, or 3) the slope of the I-V curve at the open circuit point, or 4) an estimation of that slope. Results of the solar cell/panel behavior analysis obtained with the proposed methodology, are similar to the ones obtained with the well-known 1-diode/2-resistor equivalent circuit model, in terms of accuracy.
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#### On the cup anemometer working condition monitoring

• Martínez, Alejandro
• Vega Ramiro, Enrique
• Meseguer, Encarnación
• García, Luis
• Sanz Andres, Angel Pedro
The analysis of the harmonic terms related to the rotational speed of a cup anemometer is a way to detect anomalies such as wear and tear, rotor non-symmetries (rotor damage) or problems at the output signal system. The research already done in this matter at the IDR/UPM Institute is now taken to cup anemometers working on the field. A 1-2 year testing campaign is being carried out in collaboration with Kintech Engineering. 2 Thies First Class Advanced installed at 58 m and 73 m height in a meteorology tower are constantly monitored. The results will be correlated to the anemometer performance evolution studied through several calibrations planned to be performed along the testing campaign.
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#### Estudio de la influencia del sistema de referencia en la evaluación de parámetros de acabado superficial

• Sanz Lobera, Alfredo
• Fernández, R.
• Nuñez, P.J.
In the present paper the influence of the reference system with regard to the characterization of the surface finishing is analyzed. The effect of the reference system’s choice on the most representative surface finishing parameters (e.g. roughness average Ra and root mean square values Rq) is studied. The study can also be applied to their equivalent parameters in waviness and primary profiles. Based on ISO and ASME standards, three different types of regression lines (central, mean and orthogonal) are theoretically and experimentally analyzed, identifying the validity and applicability fields of each one depending on profile’s geometry
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#### Design and development of a 5-Channel Arduino-Based Data Acquisition System (ABDAS) for experimental aerodynamics research

• Vidal Pardo, Antonio
In this work, a new and low-cost Arduino-Based Data Acquisition System (ABDAS) for use in an aerodynamics lab is developed. Its design is simple and reliable. The accuracy of the system has been checked by being directly compared with a commercial and high accuracy level hardware from National Instruments. Furthermore, ABDAS has been compared to the accredited calibration system in the IDR/UPM Institute, its measurements during this testing campaign being used to analyzed two different cup anemometer frequency determination procedures: counting pulses and the Fourier transform. The results indicate a more accurate transfer function of the cup anemometers when counting pulses procedure is used.
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#### CDF as a tool for space engineering master's student collaboration and concurrent design learning

• Bermejo, J.
• Álvarez, J.M.
• Arcenillas, P.
• Roibas-Millan, Elena
• Cubas Cano, Javier
The IDR/UPM Institute (Instituto Universitario de Microgravedad ‘Ignacio da Riva’) established a Concurrent Design Facility (CDF) for space mission design in 2011. This facility is used primarily for academic purposes within the Master in Space Systems (MUSE) 1 organized and managed by IDR/UPM also. This CDF is based on the Open Concurrent Design Tool (OCDT) from ESA, which allowed a group of students from the master to participate in the Concurrent Engineering Challenge organized by ESA Academy in September 2017. Since the early days of this facility, the development of tools and utilities for space mission design has been conducted by aerospace engineering students at IDR/UPM under the direction of professors. At present, MUSE students are programming a new set of models for the main spacecraft subsystems, to analyze space missions beyond Earth. In order to make easier for MUSE students to achieve a proper level of knowledge and experience in Concurrent Design, a frame of cooperation has been established between the students from the first year, who are new to concurrent engineering, and second-year students, that have gathered a significant level of experience in the previous year. This cooperation enables the comprehensive and resource-effective use of the CDF and ensures the success in the academic skills related to space systems engineering and mission design. It should be also said that this cooperation between two different year students is carried out through different activities conducted in the CDF, involving Concurrent Design (CD) of space missions, and working with the available material of own creation. Through this method, collaboration and communications skills are improved. Additionally, Concurrent Design concepts are more easily learnt. In the present work the activities in relation to this process of cooperation are described, how they fit in the master’s academic program, and the results of the method implementation during the academic year 2017/2018. It also includes the working methodology employed in the CDF, developed mainly by students and that is being improved progressively with each new student generation.
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#### The spanish contribution to the 1st ESA academy's concurrent engineering challenge : design of the moon explorer and observer of water-ice (meow) mission

• Roibás Millán, Elena
• Sorribes Palmer, Felix
• Chimeno Manguan, Marcos
• Cubas Cano, Javier
The IDR/UPM Institute1 (Instituto Universitario de Microgravedad ‘Ignacio da Riva’) joined the 1st European Space Agency (ESA) Academy’s Concurrent Engineering Challenge in September 2017. The aim of this Challenge was to gather around students of different ESA members or associated States to design a mission in the ESA Educational Concurrent Design Facility (CDF). Three more groups from Universidad Politécnica de Madrid (Spain), Politecnico di Torino (Italy), and University of Strathclyde (United Kingdom) were invited to join the Challenge. The purpose of this exercise was the design of a mission proposed by ESA. Universidad Politécnica de Madrid (UPM) was represented by students and professors from the Master in Space Systems (Máster Universitario en Sistemas Espaciales - MUSE2), who successfully developed a full mission (Moon Explorer and Observer of Water-ice -MEOW-), which is described in the present work. This mission fulfilled all ESA requirements. In this paper the educational point of view is described (students preparation, challenges encountered, lessons learned, etc.).
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#### UPMSat-2 ACDS magnetic sensors test campaign

• Rodríguez-Rojo, Elena
• Cubas Cano, Javier
• Piqueras Carreño, Javier
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.
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#### Lithium-ion battery performance modeling based on the energy discharge level

• Porras Hermoso, Ángel Luis
• Cubas Cano, Javier
In the present work, a new model for Li-ion battery performance is proposed. This model is based on the energy discharge level (in relation to full capacity), and was developed after testing carried out on the battery of the UPMSat-2 satellite. These thermal vacuum chamber tests showed extremely high energy efficiencies. The results from the proposed model reproduce the test results (discharging/charging processes) of a 17.2 A centerdot h Li-ion battery.
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Proyecto:

#### Ultra-violet imaging of the night-time earth by EUSO-Balloon towards space-based ultra-high energy cosmic ray observations

• Abdellaoui, G.
• Abe, S.
• Ahriche, A.
• Allard, D.
• Allen, L.
• Alonso, G.
• Anchordoqui, L.
• Anzalone, A.
• Arai, Y.
• Asano, K.
• Atallah, R.
• Attoui, H.
• Ave Pernas, M.
• Bacholle, S.
• Bakiri, M.
• Baragatti, P.
• Barrillon, P.
• Belloti, R.
• Belov, A.
• Belov, K.
• Benmessai, K.
• Bertaina, M.
• Biermann, P.L.
• Biktemerova, S.
• Bisconti, F.
• Blanc, N.
• Blçcki, J.
• Blin-Bondil, S.
• Bobik, P.
• Bogomilov, M.
• Bozzo, E.
• Briz, S.
• Bruno, A.
• Caballero, K.S.
• Cafagna, F.
• Campana, D.
• Capdevielle, J.-N.
• Capel, F.
• Caramete, A.
• Caramete, L.
• Carlson, P.
• Caruso, R.
• Casolino, M.
• Cassardo, C.
• Castellina, A.
• Catalano, C.
• Catalano, O.
• Cellino, A.
• Chikawa, M.
• Chiritoi, G.
• Christl, M.J.
• Connaughton, V.
• Conti, L.
• Cordero, G.
• Cotto, G.
• Crawford, H.J.
• Cremonini, R.
• Csorna, S.
• Cummings, A.
• Dagoret-Campagne, S.
• Castro, A.J. de
• De Donato, C.
• Taille, C. de la
• De Santis, C.
• Peral, L. del
• Di Martino, M.
• Diaz Damian, A.
• Djemil, T.
• Dutan, I.
• Ebersoldt, A.
• Ebersoldt, A.
• Ebisuzaki, T.
• Engel, R.
• Eser, J.
• Fenu, F.
• Fernández- González, S.
• Ferrarese, S.
• Flamini, M.
• Fornaro, C.
• Fouka, M.
• Franceschi, A.
• Franchini, Sebastián
• Fuglesang, C.
• Fujii, T.
• Fujimoto, J.
• Fukushima, M.
• Galeotti, P.
• García Ortega, E.
• Garipov, G.
• Gascón, E.
• Genci, J.
• Giraudo, G.
• Gorodetzky, P.
• Greg, R.
• Guarino, F.
• Guzmán, A.
• Hachisu, Y.
• Haiduc, M.
• Harlov, B.
• Haungs, A.
• Hernández Carretero, J.
• Hidber Cruz, W.
• Ikeda, D.
• Inoue, N.
• Inoue, S.
• Isgrò, F.
• Itow, Y.
• Jammer, T.
• Jeong, S.
• Joven, E.
• Judd, E.G.
• Jung, A.
• Jochum, J.
• Kajino, F.
• Kajino, T.
• Kalli, S.
• Kaneko, I.
• Karczmarczyk, J.
• Katahira, K.
• Kawai, K.
• Kawasaki, Y.
• Khales, H.
• Khrenov, B.A.
• Kim, Jeong-Sook
• Kim, Soon-Wook
• Kleifges, M.
• Klimov, P.A.
• Kolev, D.
• Krantz, H.
• Kreykenbohm, I.
• Krizmanic, J.F.
• Kudela, K.
• Kurihara, Y.
• Kusenko, A.
• Kuznestov, E.
• La Barbera, A.
• Lachaud, C.
• Lahmar, H.
• Lakhdari, F.
• Lee, J.
• Licandro, J.
• López Campano, L.
• López, F.
• Maccarone, M.C.
• Mackovjak, S.
• Mahdi, M.
• Maravilla, D.
• Marcelli, L.
• Marcos, J.L.
• Marini, A.
• Marszal, W.
• Martens, K.
• Martin, Y.
• Martínez, O.
• Matthews, J.N.
• Mebarki, N.
• Medina-Tanco, G.
• Mendoza, M.A.
• Menshikov, A.
• Merino, A.
• Meseguer, J.
• Meyer, S.S.
• Mimouni, J.
• Miyamoto, H.
• Mizumoto, Y.
• Monaco, A.
• Morales de los Ríos, J.A.
• Moretto, C.
• Nagataki, S.
• Naitamor, S.
• Napolitano, T.
• Nava, R.
• Neronov, A.
• Nomoto, K.
• Nonaka, T.
• Ogawa, T.
• Ogio, S.
• Ohmori, H.
• Olinto, A.V.
• Orleanski, P.
• Osteria, G.
• Pagliaro, A.
• Painter, W.
• Panasyuk, M.I.
• Panico, B.
• Parizot, E.
• Park, I.H.
• Pastircak, B.
• Patzak, T.
• Paul, T.
• Pérez Grande, Isabel
• Perfetto, F.
• Peter, T.
• Picozza, P.
• Piotrowski, L.W.
• Piraino, S.
• Placidi, L.
• Plebaniak, Z.
• Pliego, S.
• Pollini, A.
• Polonsky, Z.
• Popescu, E.M.
• Prat, P.
• Prévôt, G.
• Prieto, H.
• Puehlhofer, G.
• Putis, M.
• Rabanal, J.
• Reyes, M.
• Ricci, M.
• Rodríguez Frías, M.D.
• Ronga, F.
• Roudil, G.
• Rusinov, I.
• Rybczynski, M.
• Sabau, M.D.
• Sáez Cano, G.
• Sagawa, H.
• Sahnoune, Z.
• Saito, A.
• Sakaki, N.
• Salazar, H.
• Sanchez Balanzar, J.C.
• Sanchez, J.L.
• Santangelo, A.
• Sanz Andres, Angel Pedro
• Sanz Palomino, M.
• Saprykin, O.
• Sarazin, F.
• Sato, M.
• Schanz, T.
• Schieler, H.
• Scotti, V.
• Selmane, S.
• Semikoz, D.
• Serra, M.
• Sharakin, S.
• Shimizu, H.M.
• Shinozaki, K.
• Shirahama, T.
• Spataro, B.
• Stan, I.
• Sugiyama, T.
• Supanitsky, D.
• Suzuki, M.
• Szabelska, B.
• Szabelski, J.
• Tajima, N.
• Tajima, T.
• Takahashi, Y.
• Takami, H.
• Takeda, M.
• Takizawa, Y.
• Talai, M.C.
• Tenzer, C.
• Thomas, S.B.
• Tibolla, O.
• Tkachev, L.
• Tokuno, H.
• Tomida, T.
• Tone, N.
• Toscano, S.
• Traïche, M.
• Tsenov, R.
• Tsuno, K.
• Tubbs, J.
• Turriziani, S.
• Uchihori, Y.
• Valdés García, J.F.
• Vallania, P.
• Vankova, G.
• Vigorito, C.
• Villaseñor, L.
• Vlcek, B.
• Von Ballmoos, P.
• Vrabel, M.
• Watanabe, J.
• Watts Jr, J.
• Weber, M.
• Weigand Muñoz, M.
• Weindl, A.
• Wiencke, L.
• Wille, M.
• Wilms, J.
• Wlodarczyk, Z.
• Yamamoto, T.
• Yang, J.
• Yano, H.
• Yashin, I.V.
• Yonetoku, D.
• Yoshida, S.
• Young, R.
• Zgura, I.S.
• Zotov, M.Yu.
• Zuccaro Marchini, A.
The JEM-EUSO (Joint Experiment Missions for the Extreme Universe Space Observatory) program aims at developing Ultra-Violet (UV) fluorescence telescopes for efficient detections of Extensive Air Showers (EASs) induced by Ultra-High Energy Cosmic Rays (UHECRs) from satellite orbit. In order to demonstrate key technologies for JEM-EUSO, we constructed the EUSO-Balloon instrument that consists of a  ∼ 1 m2 refractive telescope with two Fresnel lenses and an array of multi-anode photo-multiplier tubes at the focus. Distinguishing it from the former balloon-borne experiments, EUSO-Balloon has the capabilities of single photon counting with a gate time of 2.3 μs and of imaging with a total of 2304 pixels. As a pathfinder mission, the instrument was launched for an 8 hour stratospheric flight on a moonless night in August 2014 over Timmins, Canada. In this work, we analyze the count rates over  ∼ 2.5 hour intervals. The measurements are of diffuse light, e.g. of airglow emission, back-scattered from the Earth’s atmosphere as well as artificial light sources. Count rates from such diffuse light are a background for EAS detections in future missions and relevant factor for the analysis of EAS events. We also obtain the geographical distribution of the count rates over a  ∼ 780 km2 area along the balloon trajectory. In developed areas, light sources such as the airport, mines, and factories are clearly identified. This demonstrates the correct location of signals that will be required for the EAS analysis in future missions. Although a precise determination of count rates is relevant for the existing instruments, the absolute intensity of diffuse light is deduced for the limited conditions by assuming spectra models and considering simulations of the instrument response. Based on the study of diffuse light by EUSO-Balloon, we also discuss the implications for coming pathfinders and future space-based UHECR observation missions.
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