Javier Cubas

Universidad Politécnica de Madrid | UPM · Instituto Universitario de Microgravedad "Ignacio da Riva"

Robotic Astronomical Observatories (RAOs) have provided very good results in different research projects in astrophysics/astronomy. Their applications in the detection, tracking, and identification of near-Earth objects have contributed to the identification of potentially dangerous objects for our security, such as near-Earth Objects (NEOs), near-...

Attitude determination is a fundamental task of the Attitude Determination and Control Subsystem (ADCS). It involves determining the spacecraft’s orientation with respect to a reference system and calculating its angular velocity, which is essential for understanding where the payload is pointing and the spacecraft’s stability. The determination of...

In the last decade, there has been a significant increase in the use and launch of small satellites. Initially, universities dominated the field, launching small satellites for use in scientific research or as technological demonstrators. However, there has been a gradual increase in the number of small satellites launched for commercial purposes....

This paper studies the performance of a new magnetic attitude control law developed for the UPMsat-2 satellite. The UPMsat-2 control law, which is a modification of the B-dot, allows the satellite to align one axis with the normal to the orbital plane and achieve a target angular velocity, without requiring attitude determination. The study evaluat...

Explaning Solar parameters Extraction Method using analytic approach, The approach was raised by Javier Cubas in his paper "On the analytical approach for modeling photovoltaic systems behavior." The hand writing notes simplify deduction of the formula in details to help researchers to get ready formulas, Which will be used to extract PV solar ce...

In the present paper, the UPMQube PocketQube proposal for the EU2Space challenge is described. This proposal has been developed by a group of master's degree students led by Ph.D. students and professors from the Instituto Universitario de Microgravedad "Ignacio Da Riva" (IDR/UPM) at Universidad Politécnica de Madrid (UPM). PocketQube is a recent n...

This article summarises the work related to the calibration methodology of the Attitude, Control and Determination Subsystem (ADCS) sensors used in the UPMSat-2 mission project, a 50 kg satellite designed and manufactured by the Universidad Polit ́ecnica de Madrid. The ADCS sensors are two fluxgate magnetometers whose calibration is essential to ob...

LiteBIRD is a future satellite mission designed to observe the polarization of the cosmic microwave background radiation in order to probe the inflationary universe. LiteBIRD is set to observe the sky using three telescopes with transition-edge sensor bolometers. In this work we estimated the LiteBIRD instrumental sensitivity using its current desi...

Space-telescopes on board satellites placed in the Sun-Earth second Lagrangian point (L2) observe the sky following a scan strategy that is usually based on a spin-precession motion. In previous studies, the authors have derived analytic solutions for quantities that characterize the observation of each point in the sky in terms of observation time...

Solar panels are a key component for most spacecraft as they provide energy to the vehicle. However, their possible use is not limited only to power generation, as they can also be used as solar sensors for attitude determination. To calculate the direction of the Sun, photovoltaic models (two of them explicit, and the well-known 1-D/2-R equivalent...

Feedhorn- and orthomode transducer- (OMT) coupled transition edge sensor (TES) bolometers have been designed and micro-fabricated to meet the optical specifications of the LiteBIRD high frequency telescope (HFT) focal plane. We discuss the design and optical characterization of two LiteBIRD HFT detector types: dual-polarization, dual-frequency-band...

En este trabajo se muestra de forma resumida el proceso de monitorización y mantenimiento, entendiendo por éste el equilibrado, de la batería del satélite universitario UPMSat-2. Este proceso fue empleado a lo largo de un extenso periodo, ya que entre la entrega de la batería por el fabricante y el lanzamiento del satélite transcurrieron más de cin...

In the present paper, the UPMQube PocketQube proposal for the EU2Space challenge is described. This proposal has been developed by a group of master's degree students led by Ph.D. students and professors from the Instituto Universitario de Microgravedad "Ignacio Da Riva" (IDR/UPM) at Universidad Politécnica de Madrid (UPM). PocketQube is a recent n...

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 a...

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...

PIRAMIDE aimed at boosting academic results from Bachelor and Master students by doing research on space engineering. This project was carried out by professors from the IDR/UPM Institute and the STRAST group. The program was structured into five different case studies: 1) design of a space mission (phase 0/A) in a Concurrent Design Facility (CDF);...

Scientific instruments on board satellites are becoming increasingly sensitive, making it imperative to submit these instruments to a thorough calibration. In-flight calibration could be largely improved by using an ancillary microsatellite flying in formation with the main satellite and emitting a well-defined and known reference signal. Due to th...

Mubody is an astrodynamics open-source Python library focused on the libration points. Such points result from the equilibrium of the gravitational forces between two massive bodies as the Sun and Earth, for example. The library is mainly intended for the generation of orbits in these regions, which is not a straightforward process, specially if pe...

In the present work, a method for magnetometer calibration through least squares fitting is presented. This method has been applied over the magnetometer’s data set obtained during the integration tests of the Attitude Determination and Control Subsystem (ADCS) of UPMSat-2. The UPMSat-2 mission is a 50-kg satellite designed and manufactured by the...

Attitude determination represents a fundamental task for most of the spacecrafts. It relies on three basic aspects: 1) sensors selection, 2) relevant environmental conditions estimation, and 3) algorithms that relate the sensor measurements to the expected conditions in the reference frame. Each one has its own impact on the accuracy that the syste...

PIRAMIDE aimed at boosting academic results from Bachelor and Master students by doing research on space engineering. This project was carried out by professors from the IDR/UPM Institute and STRAST group. The program was structured into five different case studies: 1) Design of a space mission (phase 0/A) in a Concurrent Design Facility (CDF); 2)...

Nanostar emerges as a project funded by INTERREG-SUDOE through the European Regional Development Fund (ERDF) aiming to develop a collaborative platform in Europe for nanosatellite hands-on education and training in space engineering. One of the major project goals was to develop a set of open-source tools for nanosatellite subsystems design, which...

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 Spacecraf...

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 yea...

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...

The thermal modeling of small satellites (up to 100 kg) is crucial for predicting and managing their operation, and may present significant differences when compared to the thermal modeling carried out in relation to larger spacecraft. In this article, the modeling of their solar panels is underlined as one of these differences. The efficiency of s...

By the end of 2019, Technical University of Madrid (Universidad Politécnica de Madrid - UPM) from Spain granted support to the 1-year innovative educational project PIRAMIDE, within the call for projects Innovative Education Program of UPM . PIRAMIDE aimed at boost academic results from Bachelor and Master students by doing research on space engine...

In this work, the use of a calibration satellite (L2-CalSat) flying in formation with a Cosmic Microwave Background (CMB) polarization mission in an orbit located at the second Lagrange point, is proposed. The new generation of CMB telescopes are expected to reach unprecedented levels of sensitivity to allow a very precise measurement of the B-mode...

In this paper, we propose very simple analytical methodologies for modeling the behavior of photovoltaic (solar cells/panels) using a one-diode/two-resistor (1-D/2-R) equivalent circuit. A value of a = 1 for the ideality factor is shown to be very reasonable for the different photovoltaic technologies studied here. The solutions to the analytical e...

The most relevant results from the IDR/UPM Institute research on solar cells/panels and Li-ion batteries performance are reviewed in this paper. The aim of this work is to present the possibilities of the mathematical procedures developed for space applications, with a view to extend their use to other industrial sectors. The research at the IDR/UP...

Este trabajo está ligado al Proyecto de Innovación educativa PIRAMIDE (Proyectos de Investigación Realizados por Alumnos de Máster/Grado para la Innovación y el Desarrollo Espacial), dirigido por los Profesores Elena Roibás-Millán y Santiago Pindado. El informe se desarrolló en 2019/2020 como parte del trabajo desarrollado por el grupo 4, dedicado...

In this article, simplified and easy-to-work-with equations for the Lambert W-function are derived. This function is widely used to solve equations related to photovoltaic systems. More specifically, this mathematical function represents a useful tool when modeling solar cells/panels performance (that is, the current-voltage curve) by analytical ap...

To progress towards as quick as possible feasible pre-design of space missions, spacecraft early design today is organized gathering together experts from different spacecraft subsystems that share information (and results). This Concurrent Design (CD) approach needs accurate but quick solutions from all subsystems involved in each phase of that mi...

LiteBIRD is a JAXA-led Strategic Large-Class mission designed to search for the existence of the primordial gravitational waves produced during the inflationary phase of the Universe, through the measurements of their imprint onto the polarization of the cosmic microwave background (CMB). These measurements, requiring unprecedented sensitivity, wil...

LiteBIRD, the Lite (Light) satellite for the study of B-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission for primordial cosmology and fundamental physics. JAXA selected LiteBIRD in May 2019 as a strategic large-class (L-class) mission, with its expected launch in the late 2020s using JAXA's H3 rocket. L...

LiteBIRD has been selected as JAXA's strategic large mission in the 2020s, to observe the cosmic microwave background (CMB) $B$-mode polarization over the full sky at large angular scales. The challenges of LiteBIRD are the wide field-of-view (FoV) and broadband capabilities of millimeter-wave polarization measurements, which are derived from the s...

LiteBIRD, the Lite (Light) satellite for the study of B-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission for primordial cosmology and fundamental physics. JAXA selected LiteBIRD in May 2019 as a strategic large-class (L-class) mission, with its expected launch in the late 2020s using JAXA's H3 rocket. L...

LiteBIRD has been selected as JAXA’s strategic large mission in the 2020s, to observe the cosmic microwave background (CMB) B-mode polarization over the full sky at large angular scales. The challenges of LiteBIRD are the wide field-of-view (FoV) and broadband capabilities of millimeter-wave polarization measurements, which are derived from the sys...

LiteBIRD is a JAXA-led Strategic Large-Class mission designed to search for the existence of the primordial gravitational waves produced during the inflationary phase of the Universe, through the measurements of their imprint onto the polarization of the cosmic microwave background (CMB). These measurements, requiring unprecedented sensitivity, wil...

La modelización del comportamiento de paneles solares es un aspecto de especial interés para gran cantidad de proyectos espaciales. En el Instituto IDR/UPM se ha constatado en los últimos años la necesidad de contar con modelos de simulación lo más simples posible (sin devaluar su precisión) ante la necesidad de realizar cálculos en procesos de dis...

El satélite universitario UPMSat-2 fue lanzado el 2 de septiembre de 2020 desde la Guayana Francesa en un vehículo lanzador VEGA, dentro de la misión VV16, que incluía la puesta en órbita de 7 micro-satélites y 46 nano-satélites. Con este hito se completaba la primera parte de una misión que comenzó oficialmente en 2011, y que había sido precedida...

Correct thermal modelling is crucial for smallsats. They can experience higher variations of temperatures and their components usually have a lower range of safe operating temperatures, especially if they are COTS (Commercial-Off-The-Shelf). This can make the thermal design more difficult and also, in certain aspects, very different when compared t...

Nowadays most universities are focused in the development and use of innovative educational programs, in a search for improvements in their academic plans. Within innovative educational techniques, Research-Based Learning (RBL) is focused on the generation of didactic experiences based on the scientific method (questions formulation, finding of ans...

In this paper, the first work carried out at the IDR/UPM Institute within the frame of the educational innovation project PIRAMIDE is presented. This work is related to photovoltaic behavior modeling simplification. The aim is to derive simplified and easy-to-work-with equations for the Lambert W-function. This mathematical function represents a qu...

In this paper the work carried out at the IDR/UPM Institute on photovoltaic devices' performance is outlined. The aim of the work is to demonstrate the possibilities of the mathematical procedures developed beyond the space applications, in order to show them to other industrial sectors. The work carried out at the IDR/UPM Institute have been drive...

The last integration and testing procedures of the UPMSat-2 are described in this presentation.

The determination of analytical solutions is a vital step in understanding the different physical systems and building confidence in the numerical methods that are required for more complex models. In the present work, analytical solutions are derived for axisymmetric and near-axisymmetric rigid body problems. The formulation proposed is based on a...

In this article, a magnetic control without attitude determination for spinning spacecraft is presented. The control only uses magnetorquers as actuators and sun-sensors and magnetometers as sensors. An equilibrium angular velocity is reached by using two magnetic moments at the same time; the first one is a B-dot control that produces a despinning...

The new generation of cosmic microwave background (CMB) telescopes have reached unprecedented levels of sensitivity. These telescopes measure several cosmological parameters with different levels of accuracy. In particular, considerable effort has been made to measure the B-mode polarization, which is related to the inflationary process of the univ...

In the present paper the work carried out in relation to the Attitude, Control and Determination Subsystem (ACDS) of the UPMSat-2 is summarized. This engineering project is integrated within the UPMSat-2 mission framework. This 50-kg satellite has been designed and manufactured by the Polytechnic University of Madrid (Universidad Politécnica de Mad...

The present document summarizes the work carried out by the IDR/UPM Institute in relation to the development of Analytical models of Li-ion batteries. The proposed models are based on the energy discharge level (in relation to full capacity). This represents a new approach in relation to battery assessment with applications at the design phases of...

When compared with Cartesian coordinates, curvilinear coordinates have shown significant superior accuracy when applied to a linear model for relative motion in a circular reference orbit. Experts assume the same superiority for an elliptical reference orbit. However, the curvilinear model in an elliptical reference orbit has not been established,...

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 propos...

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 Desig...

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 T...

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...