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Mars has been a main target for exploration over the last decades, due to its closeness and similarity to Earth. Exploration landers and rovers have laid the foundation for the understanding of the planet, however, they exhibit some limitations that Unmanned Aerial Vehicles (UAVs) would overcome. Thus, this report consists of the design of a swarm of UAVs for the exploration of the red planet, which coordinates with a swarm of rovers and a constellation of orbiters that are briefly described. Firstly, the mission is preliminarily designed to define its location, architecture, objectives, and requirements. Secondly, the single UAV overview is presented, illustrating a preliminary design of all the subsystems involved in order to perform successfully. Thirdly, the swarm of UAVs is defined, introducing pre-flight check procedures. Then, two flight formation algorithms for the swarm of UAVs are suggested, although only one of them is implemented. Fourthly, there is a brief introduction to the multiplatform architecture, focused on communication and connectivity. Finally, conclusions are drawn and and the foundation for future work related to the different chapters of this thesis is included.

The competence to apply ethics in the development of new technologies is currently not addressed in university programs for aerospace engineering at the national level. Therefore, the purpose of this project is to guide future aerospace engineers in making ethical decisions. This project is divided into three different parts. In the first one, different teaching methodologies are studied. Active learning, which includes case studies, is concluded to be the most effective for students. In the second part, using these methodologies, the syllabus for an elective on ethics for the aerospace engineering curriculum has been developed. This syllabus covers important moral concepts in the design, development, testing, and certification processes, as well as the concept of responsibility. Finally, in the third part, a teaching guide has been developed, divided into each session, to carry out the instruction of this course. After all, this project has successfully fulfilled all its initial requirements and developed a course that is ready to be taught.

This thesis presents the design and development process of a PocketQube picosatellite prototype deployment system for an electrodynamic tether in the conditions of a low Earth orbit. The project was undertaken as part of the EU2Space challenge organized by HydraSpace company, with the mechanics team of the Horus mission from the UPC Space Program initiative leading the effort. Through an iterative approach, various methods were proposed and evaluated to address the unique challenges associated with the deployment. The team utilized critical thinking, meticulous analysis, and effective teamwork to navigate the constraints set by the company. The proposed approaches are presented, showcasing the rationale behind each method and the considerations taken into account to meet the stringent requirements set by HydraSpace. Throughout the project, the team encountered numerous difficulties, which provided valuable learning experiences. The successful design and development of a PocketQube picosatellite prototype capable of deploying an electrodynamic tether not only contributes to the EU2Space challenge but also might be the beginning for an understudied topic such as electrodynamic tethers’ utility can be in space missions.

En los últimos años, el número de satélites en el espacio ha crecido debido a la demanda de servicios basados en satélites. Los satélites pueden proporcionar distintos servicios, como por ejemplo, proporcionar servicios de telecomunicaciones (como telefonía, televisión, transmisión de datos, etc), observación de la Tierra, navegación y posicionamiento, meteorología, etc. Hasta el momento, la comunicación entre estaciones terrenas y satélite o entre satélites se ha basado en una comunicación por enlace RF. Sin embargo, recientemente ha despertado la necesidad de mejorar el sistema y permitir el intercambio de una mayor información en los enlaces de subida y bajada (Bit Rate). Además, el gran número de satélites orbitando la Tierra con diferentes finalidades afecta a la disponibilidad limitada del espectro de RF, la cual está firmemente regulada. De esta manera nace un nuevo tipo de comunicación basado en enlaces ópticos (Free Space Optic, FSO). Las comunicaciones FSO utilizan luz láser para transmitir información. Estas señales son transmitidas por un haz de luz que se propaga a través del espacio y es capturado por un receptor óptico. La ventaja de las comunicaciones FSO es que pueden transmitir grandes cantidades de información a velocidades extremadamente altas, superando incluso a las comunicaciones RF. Además, las señales FSO son inmunes a las interferencias electromagnéticas y son muy difíciles de interceptar, lo que las hace altamente seguras. Con el objetivo de analizar el comportamiento de las comunicaciones FSO, y realizar una comparación a nivel técnico y económico con las comunicaciones RF, surge el presente proyecto. En este, se ha propuesto una misión, la cual puede ser llevada a cabo por 4 casos distintos que combinan comunicaciones RF y FSO, además de distintas configuraciones orbitales. Esta misión se basa en el envío de información que una estación en Amazonas recibe (fotos, vídeos, datos, etc). La información enviada desde la estación en Amazonas s

Operating satellites in Very Low Earth Orbit (VLEO) benefit the already expanding New Space industry in applications including Earth Observation and beyond. However, long-term operations at such low altitudes require propulsion systems to compensate for the large aerodynamic drag forces. When using conventional propulsion systems, the amount of storable propellant limits the maximum mission lifetime. The latter can be avoided by employing Atmosphere-Breathing Electric Propulsion (ABEP) system, which collects the residual atmospheric particles and uses them as propellant for an electric thruster. Thus, the requirement of on-board propellant storage can ideally be nullified. At the Institute of Space Systems (IRS) of the University of Stuttgart, an intake, and a RF Helicon-based Plasma Thruster (IPT) for ABEP system are developed within the Horizons 2020 funded DISCOVERER project. To assess possible future use cases, this paper proposes and analyzes several novel ABEP-based mission scenarios. Beginning with technology demonstration mission in VLEO, more complex mission scenarios are derived and discussed in detail. These include, amongst others, orbit maintenance around Mars as well as refuelling and space tug missions. The results show that the ABEP system is not only able to compensate drag for orbit maintenance but also capable of performing orbital maneuvers and collect propellant for applications such as Space Tug and Refuelling. Thus, showing a multitude of different future mission applications., This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 737183. This reflects only the author’s view, and the European Commission is not responsible for any use that may be made of the information it contains, Peer Reviewed, Postprint (author's final draft)

The DISCOVERER project commenced in 2017 with the aim to advance the development of key technologies to enable the commercially viable, sustained operation of satellites in very low Earth orbits (VLEO). Funded by the European Commission through Horizon 2020, the project ends this month. This paper presents an overview of the key achievements and current status of the project. The project set out to advance the development of, and demonstrate, several technologies with the long-term aim of enabling the commercial use of VLEO. These technologies include: 1. aerodynamic materials which encourage specular scattering of the incoming flow to minimise drag and increase the performance of aerodynamic surfaces in the highly rarefied flows experienced in VLEO 2. aerodynamic attitude control methods to compensate for the dynamic flow environment, especially lower in the VLEO altitude range 3. atmosphere breathing electric propulsion (ABEP), combining an optimised atmospheric intake with advanced RF Helicon-based plasma thruster, for drag compensation DISCOVERER’s test satellite, the Satellite for Orbital Aerodynamics Research or SOAR, was deployed from the International Space Station in June 2021 and re-entered the atmosphere in March 2022. The primary aim was to measure the induced drag and lift on different aerodynamic materials candidates in VLEO by exposing panels, coated in various novel and control materials, to the flow at different orientations whilst observing the induced attitude and orbit perturbations produced. Early analysis of the results from the mission shows promising results for the novel materials developed as part of the project. Parallel studies on the long-term survivability of these materials to the space environment have been on-going through exposure tests on the exterior of the International Space Station through the MISSE programme. The project has also been developing a ground-based facility, the Rarefied Orbital Aerodynamics Research facility, to c, Peer Reviewed, Article signat per 30 autors: Peter C.E. Roberts, Nicholas H. Crisp, Steve Edmondson, Antonio Arcos, Georg H. Herdrich, Jonathan Skalden, Silvia Rodriguez-Donaire, Daniel Garcia-Almiñana, Alejandro Macario-Rojas, Katharine L. Smith, Ciara Mcgrath, Sarah J. Haigh, Vitor T.A. Oiko, Brandon E.A. Holmes, Luciana A. Sinpetru, Virginia Hanessian, Simon Christensen, Thomas Kauffman Jensen, Jens Nielsen, Morten Bisgaard, Francesco Romano, Stefanos Fasoulas, Constantin Traub, Konstantinos Papvramidis, Miquel Sureda, Dhiren Kataria, Badia Belkouchi, Alexis Conte, Simon Seminari, Rachel Villain, Postprint (published version)

This project aims to study the quality of communication using nanosatellites in LEO orbits. The objective is to study the signal attenuation by radio frequency (RF) antennas between a nanosatellite and a ground station, or another nanosatellite. For this purpose, a MATLAB simulator is developed that allows the modeling of satellite orbits by using TLEs, orbital elements or Walker constellations. As for the communication parameters, different transmission frequencies and atmospheric propagation models can be used. As for the antennas, two different types are used: parabolic reflectors for ground stations and patch antennas for satellites. The quality of a communication link is determined by two different methods: using the received power or the signal-to-noise ratio in reception. In the case of received power, this should be higher than the sensitivity of the transceiver under study, while signal-to-noise takes into account different digital modulations that determine the probability of message loss. Thanks to this simulator, it is possible to obtain results that determine the visibility times between satellites and/or ground stations, and to determine if the communication for a given link meets the minimum communication requirements, as well as to calculate the transmission power necessary to meet these requirements. It also performs a 3D representation in which the orbits of the satellites as well as the ground stations can be observed.

Very Low Earth Orbits (VLEOs), those below 450 km, present a number of benefits and challenges for the development and operation of Earth observation spacecraft at both the system and mission level. This paper examines the design of constellations of satellites for operation in VLEO for Earth observation considering both system and mission level trade-offs. The resulting analysis identifies general design trends and proposes suitable mission architectures for Earth observation from VLEO. The principal benefit for satellites operating in VLEO is that the reduction in the distance to the Earth’s surface allows better imaging resolution to be achieved using smaller and less powerful payloads. This has corresponding benefits for the system mass and cost. However, the sustained and controlled operation of spacecraft in VLEO is challenging due to the increased atmospheric density at these altitudes, which increases propulsive and attitude control requirements. Technologies to facilitate the commercially viable operation of spacecraft in VLEO are currently being developed, for example materials to facilitate drag-reduction and aerodynamic control and atmosphere-breathing electric propulsion systems (ABEP), each of which influence the design of other sub-systems, requiring, for example, varying levels of power or new geometric considerations. At the mission level, the reduction in altitude has a generally negative influence on the coverage and revisit characteristics of a given satellite. However, deployment of these satellites in constellations can provide improvements in the overall system metrics. Systems operating in VLEO may also benefit from improved launch vehicle capability and assured end-of-life deorbit. It is clear, therefore, that important and non-intuitive trade-offs between the satellite platform design, constellation configuration, and total cost arise in the design of these systems. This paper uses combined platform-level system modelling and mission analys, Peer Reviewed, Postprint (published version)

CubeSats are making space exploration more accessible are are being launched in greater numbers than ever before. In order to enable their use for optical communication links between satellite constellations, precise and reliable attitude determination and control systems (ADCS) are needed. The present thesis describes the development of a mechanical reaction wheel assembly that is built from off-the-shelf and additively manufactured components for the attitude control of CubeSats. Furthermore, a numerical simulation model has been set up to simulate the attitude dynamics of a nanosatellite and validate its attitude control by a reaction wheel-based ADCS. As results of the thesis, parts for a complete mechanical assembly have been manufactured. It has been shown through simulations that the chosen reaction wheel configurations are able to effectively control the attitude of a nanosatellite even in case of a reaction wheel failure.

The Satellite for Orbital Aerodynamics Research (SOAR) is a 3U CubeSat that has been designed to investigate the aerodynamic performance of different materials and perform demonstrations of aerodynamic attitude control manoeuvres in very low Earth orbit (VLEO). SOAR was deployed from the ISS on 14th June 2021 into a naturally decaying orbit and deorbited on 14th March 2022. This paper provides an overview of the operations performed during the mission and presents preliminary experimental results obtained from this spacecraft. SOAR was designed and launched within the frame of DISCOVERER, a Horizon 2020 project that aimed to support the development of a new class of commercially viable spacecraft operating in VLEO, i.e., orbits below 450 km in altitude. Operating in these lower altitude orbits has several benefits to the design of spacecraft, particularly for Earth observation and communications applications. However, development of spacecraft that can operate sustainably at these altitudes requires advancement in foundational technologies, for example atmosphere-breathing electric propulsion (ABEP) and novel aerodynamic materials. The primary aim of SOAR was to characterise the aerodynamic performance of different materials at very low altitudes and accomplished this task using a set of steerable fins that exposed different materials to the oncoming flow and an ion and neutral mass spectrometer (INMS) to provide in-situ measurements of atmospheric properties. SOAR was also designed to perform novel aerodynamic attitude control manoeuvres and measurements of thermospheric winds. Two of the materials carried to orbit were selected for their atomic oxygen erosion resistance and potential improvement in aerodynamic performance. The identification of such materials would allow for a reduction in the drag experienced in VLEO, the design of atmospheric intakes with greater efficiency used for ABEP, and implementation of enhanced aerodynamic attitude and orbit control. Ong, Peer Reviewed, Postprint (published version)

Earth Observation (EO) is key for climate and environmental monitoring at global level, and in specific regions where the effects of global warming are more noticeable, such as in polar regions, where ice melt is also opening new commercial maritime routes. Soil moisture is also useful for agriculture and monitoring the advance of desertification, as well as biomass and carbon storage. Global Navigation Satellite System - Reflectometry (GNSS-R) and L-band microwave Radiometry are passive microwave remote sensing techniques that can be used to perform these types of measurements regardless of the illumination and cloud conditions, and -since they are passive- they are well suited for small satellites, where power availability is a limiting factor. GNSS-R was tested from space onboard the UK-DMC and the UK TechDemoSat-1, and several missions have been launched using GNSS-R as main instrument, as CyGNSS, BuFeng-1, or the FSSCAT [1] mission. These missions aim at providing soil moisture [2], ocean wind speed [3], and flooding mapping of the Earth. L-band microwave radiometry data has also been retrieved from space with SMOS and SMAP missions, obtaining sea ice thickness, soil moisture, and ocean salinity data [4]. The 3Cat-4 mission was selected by the ESA Academy "Fly your Satellite" program in 2017. It aims at combining both GNSS-R and L-band Microwave Radiometry at in a low-power and cost-effective 1-Unit (1U) satellite. Moreover, the 3Cat-4 can also detect Automatic Identification System (AIS) signals from vessels. The single payload is the Flexible Microwave Payload 1 (FMPL-1) [5] that performs the signal conditioning and signal processing for GNSS-R, L-Band microwave radiometry and AIS experiments. The spacecraft has three payload antennas: (1) a VHF monopole for AIS signals; (2) an uplooking antenna for the direct GPS signals; (3) a downlooking antenna that captures reflected GPS signals, and for the Microwave Radiometer. The downlooking antenna is a deployable h

CubeSat reliability is still considered an obstacle due to the sizeable fail rates generally attributed to the dead-on-arrival cases and early subsystem malfunctions. Thus, as CubeSats' primary purpose moves from technological demonstrations and university projects to missions where a significant risk of failure is not acceptable, an inexpensive method to emulate low Earth orbit constellations is being researched. The results presented have been developed in the framework of the PLATHON research project, which intends to develop a hardware-in-the-loop emulation platform for nanosatellite constellations with optical inter-satellite communication and ground-to-satellite links. Consequently, a crucial aspect of this project is to have a sufficiently precise orbital propagator with real-time manoeuvring control and graphical representation. NASA's OpenSatKit, a multi-faceted open-source platform with an inbuilt propagator known as 42, has been chosen to analyse the programme's feasibility in order to create a constellation testing bench. As an initial development of a software-in-the-loop application, the pre- processing of files has been automated; enhanced Attitude Determination and Control System manoeuvres have been added and configured through bidirectional socket interfaces, and the results format has been modified to be easily post-processed with MATLAB and Simulink

The main purpose of this dissertation is to mechanically design an ADCS system based on Reaction Wheels for a 1U CubeSat. This document contains brief analysis of the current technologies behind attitude control in space. To aid with the mechanical design, an analysis of the components of the ADCS system is carried out, which allows to provide enough knowledge so as to establish design requirements that the reaction wheel shall comply with. The process behind the mechanical design of the reaction wheel and two different ADCS system configuration is included, as well as a description of its assembly and integration into a 1U CubeSat. Finally, with the aim of identifying the capabilities of each configuration, a software is developed. The latter, despite not contemplating disturbances and space manoeuvres, allows to verify if each configuration is capable of controlling the rotation along the three main axis of rotation of the CubeSat.

Challenging space missions include those at very low altitudes, where the atmosphere is the source of aerodynamic drag on the spacecraft, that fnally defnes the mission’s lifetime, unless a way to compensate for it is provided. This environment is named Very Low Earth Orbit (VLEO) and it is defned for h < 450km. In addition to the spacecraft’s aerodynamic design, to extend the lifetime of such missions, an efcient propulsion system is required. One solution is Atmosphere-Breathing Electric Propulsion (ABEP), in which the propulsion system collects the atmospheric particles to be used as propellant for an electric thruster. The system could remove the requirement of carrying propellant on-board, and could also be applied to any planetary body with atmosphere, enabling new missions at low altitude ranges for longer missions’ duration. One of the objectives of the H2020 DISCOVERER project, is the development of an intake and an electrode-less plasma thruster for an ABEP system. This article describes the characteristics of intake design and the respective fnal designs based on simulations, providing collection efciencies up to 94%. Furthermore, the radio frequency (RF) Helicon-based plasma thruster (IPT) is hereby presented as well, while its performances are being evaluated, the IPT has been operated with single atmospheric species as propellant, and has highlighted very low input power requirement for operation at comparable mass fow rates P ~ 60w., Peer Reviewed, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (author's final draft)

Recent climate changes have had widespread impacts on human and natural systems resulting in an increasing frequency of ecosystem disasters such as floods and droughts, windstorms or fires. They can be monitored either with space-borne or in-situ measurements and in some way be predicted in order to reduce their impact. Nevertheless, these monitoring systems are not optimal for an early detection and constant monitoring. The next generation Internet of Things (IoT) will be the key enablers for future effective disaster management infrastructures that enables to integrate large and wide technologies in satellite missions. A promising protocol in this line is NB-IoT. This new protocol has become a solution inside the LPWA networks, offering low power consumption and long battery life, transmitting data at low bit rates over long distances and scalability between others. Earth Observation satellites could take advantage of this new type of communications to achieve novel applications and provide fast responses to natural disasters monitorization. A Distribute Satellite System Simulator able to reproduce a constellation of EO satellites monitoring natural hazards with the benefit from a NB-IoT networks will be the focus of this project. The project will contribute to the DSS-SIM, a satellite simulator from i2Cat, originally from UPC. As a first step, the orbit prediction will be improved to an SGP4 model, since it only provided a two-body Kepler model. This will be done by embedding the Satellite Toolbox from Julia language in the DSS-SIM. Unfortunately, non-expected results will result in finally using a C++ solution for this orbital model upgrade. After then, the NB-IoT scenario will be included in the main source code. This scenario has been first studied and justified. A Planet Labs constellations will be justified as the satellites studied to benefit from NB-IoT networks. The Earth location where monitoring sensors is presented too with the study developed of the m

To achieve a feasible lifetime of several years, most satellites are deployed in orbits higher than 400 km. Drag of residual atmosphere causes a slow orbit decay, resulting in the deorbit of the spacecraft. However, e.g. optical instruments or communication devices would significantly benefit from lower altitudes in the range of 150-250 km. A solution to achieve this could be the application of atmosphere-breathing electric propulsion (ABEP), where the residual atmosphere is used to generate continuous thrust that compensates the drag. Within the EU-funded DISCOVERER project, the Institute of Space Systems (IRS) developed an electrode-less RF Helicon-based Plasma Thruster (IPT) suitable for such applications. Ignition and preliminary discharge characterizations of the IPT have been carried out at IRS facilities, using argon, nitrogen and oxygen. To further characterize the plasma plume, a torsional pendulum has been designed to determine the momentum flux in the plasma jet, as well as a three-axis magnetic B-dot probe to carry out time-varying magnetic field measurements. Various intake designs were investigated, opening the possibility to conduct studies on potential satellite platforms. A design study for an Earth Observation and Telecommunication satellite operating at 150-250 km with an extended mission lifetime is currently being carried out. The first system assessment focused on the comparison of different spacecraft configurations (“slender body” and “flat body”) and intake designs (specular or diffuse) with regard to overall drag and ABEP performance requirements. In this contribution, the proposed thruster characterization methods and the current status of the system assessment are presented. Upcoming experimental studies of the ABEP system and additional activities planned on system assessment are outlined., The part of the described work performed under the DISCOVERER project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 737183. This reflects only the author’s view and the European Commission is not responsible for any use that may be made of the information it contains. Part of the work is also performed under the RamCLEP project with the name "Technology Enhancement of Atmosphere-Breathing Cathode-Less Electric Propulsion“ and has received funding from ESA under the ITT AO/1-10597/20/NL/MG., Peer Reviewed, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

This work aims at studying the mechanical behaviour of nano- and pico-satellites, with CubeSats and PocketQubes as the references, and designing and producing a deployment system for PocketQubes, to be integrated in a CubeSat platform. Through this project, the 3Cat-4 spacecraft will be analysied in order to assess the impact of changes made to its architecture, both at system and subsystem level, and the results evaluation will aid in decision making regarding modifications of the mechanical components. The analyses will serve as the reference for the mechanical testing during the Environmental Test Campaign (ETC). Additionally, the response of the spacecraft against the different vibro-acoustic and mechanical loads will serve as the starting point for the design of a PocketQube P-POD (Poly-Picosatellite Orbital Deployer), which will be a major subsystem integrated in 3Cat-8, a new mission of the NanoSat Lab currently in Phase B.

Descripció del recurs: 27 juliol 2022, The 4th Symposium on Space Educational Activities (4th SSEA) was hosted at the Universitat Politècnica de Catalunya (UPC) · BarcelonaTech in Barcelona, Spain, from 27th – 29th April 2022. It was co-organized by the European Space Agency (ESA) and the UPC. The event represented the 4th edition of a successful Space Education symposium that began at the University of Padova, Italy, in 2015, followed by the 2nd Symposium hosted by the Budapest University of Technology and Economics, Hungary, in 2018, and the 3rd Symposium hosted by the University of Leicester, UK, in 2019. This long-awaited edition exceeded all expectations and gathered more than 500 attendees in Barcelona. The 4th SSEA Organizing Committee developed a compelling outreach campaign that reached to more than 2000 departments and universities. It raised support from more than 10 private companies, and it had wide support from the local, regional and country-level institutions. During the three days of the event in UPC’s venue Edifici Vèrtex, the attendees engaged in fruitful research discussions, established connections among the European sector and learned from the latest projects in space education and student-led projects. The transformation of the space sector, as a result of new technology, business and policy trends, creates new challenges for the education system, which must adapt to new sector needs. NewSpace, artificial intelligence, machine learning, additive manufacturing… All these advances create new needs for a more interdisciplinary education. This is the real meaning of an event like the Symposium on Space Educational Activities. Here we present the symposium proceedings that summarize all the presentations held during the event. We also introduce a summary of the symposium organization, events and awards., 1

The main objective of this thesis is the design and additive manufacture of various assemblies of Reaction Wheels for the Attitude Control Subsystem of a 1U CubeSat. A CubeSat is a small satellite which dimensions are 10 × 10 × 10 cm and weights 1 kg. These nanosatellites make space exploration more accessible since a lower volume of materials is needed. The mathematical models to perform numerical simulations of the reaction wheels consist of the dynamics and kinematics equations used to describe the satellite, here a quaternion representation is used. Furthermore, the derivation of the distribution matrices of each reaction wheel configuration are presented, the considered configurations are: Orthogonal, NASA Standard, Pyramid and Tetrahedral. Thereafter, the control law used for the simulation model is introduced. It was chosen to apply the typical control law for spacecraft attitude, a PD controller. This is then expressed in the quaternion feedback control, including a counteract for the gyroscopic effect of the rotating body. The Reaction Wheels mechanical design and the simulation model were established. In the mechanical design, the motor selected is the Maxon 20 EC flat. From this motor, four reaction wheel concepts are created, each one of them has a version for the NASA Standard and the Pyramid configuration. These configurations are chosen because they offer redundancy and are suitable to fit in the CubeSat constraints. The fifth concept C5 is for another motor of interest due to its reduced size. Successively, the simulation model is introduced, with an explanation of each block with their inputs and outputs. Subsequently, the concepts were 3D printed and manually assembled. Thereafter, the simulation results showed that the chosen reaction wheels can efficiently control the attitude of the satellite even when one wheel of the redundant system fails. The outcomes for this thesis are that Concept 4 of the mechanical design is the most convenient since it

The Satellite for Orbital Aerodynamics Research (SOAR) is a 3U CubeSat that has been designed to investigate the aerodynamic performance of different materials at low orbital altitudes. The spacecraft has been developed within the scope of DISCOVERER, a Horizon 2020 project that aims to develop foundational technologies to enable sustainable operations of Earth observation spacecraft in very low Earth orbits (VLEO) i.e., those below 450 km. SOAR features two payloads: i) a set of steerable fins that can expose different materials to the oncoming atmospheric flow developed by The University of Manchester, and ii) a forward-facing ion and neutral mass spectrometer (INMS) that provides in-situ measurements of the atmospheric density, flow composition, and velocity from the Mullard Space Science Laboratory (MSSL) of University College London. These payloads enable characterisation of the aerodynamic performance of different materials at very low altitudes with the aim to advance understanding of the underlying gas-surface interactions in rarefied flow environments. The satellite will also be used to test novel aerodynamic attitude control methods and perform atmospheric characterisation in the VLEO altitude range. SOAR will perform the first in-orbit test of two novel materials that are expected to have atomic oxygen erosion resistance and drag-reducing properties, providing valuable in-orbit validation data for ongoing ground-based experimentation. Such materials hold the promise for extending operations at lower altitudes with benefits particularly for Earth observation and communications satellites that can correspondingly be reduced in size and cost. The platform for SOAR is largely based on GOMX-3 heritage and the spacecraft was assembled, integrated, and tested by GomSpace A/S. The satellite was launched on the SpX-22 commercial resupply service mission to the International Space Station in on 3rd June 2021 was subsequently deployed into orbit on the 14th June 202, Article signat per 30 autors/res: Nicholas H. Crisp, Alejandro Macario-Rojas, Peter C.E. Roberts, Steve Edmondson, Sarah J. Haigh, Brandon E.A. Holmes, Sabrina Livadiotti, Vitor T.A. Oiko, Katharine L. Smith, Luciana A. Sinpetru, Jonathan Becedas, Valeria Sulliotti-Linner, Simon Christensen, Virginia Hanessian, Thomas K. Jensen, Jens Nielsen, Morten Bisgaard, Yung-An Chan, Georg H. Herdrich, Francesco Romano, Stefanos Fasoulas, Constantin Traub, Daniel Garcia-Almiñana, Silvia Rodriguez-Donaire, Miquel Sureda, Dhiren Kataria, Badia Belkouchi, Alexis Conte, Simon Seminari, Rachel Villain, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

The motivation of this thesis is to solve the two main problems of space exploration: the lack of fuel to perform space exploration beyond the Moon or Mars, and the limitations generated by the launching of large amounts of fuel from Earth to perform long distance missions. In this thesis we study the possibility of using lunar resources to produce fuel from them and not needing the raw material from Earth, the location of these resources on the Moon and the different methods to extract them. In order to favor a reliable study, a propulsive characterization test is carried out with a fuel composed only of resources available on the Moon: aluminum and oxygen. For this test, a hybrid rocket will be designed and manufactured to test the fuel. The results of this test will be used to study the effectiveness of this combination of lunar materials as a propellant. Obtaining feasible results in the test would be a milestone in space research, since it is estimated that the use of lunar resources for fuel production would drastically reduce the cost of space missions, thus allowing the possibility of solar system exploration and a future space economy. The fact of being able to obtain fuel from the Moon would expand our frontiers since it opens the door to the idea of being able to obtain it also from different bodies of the solar system. Thus, this thesis is a good starting point for future research on obtaining rocket fuel from the raw materials of other planets or asteroids, and consequently, to the long-term goal of establishing a sustainable presence on the Moon

Challenging space missions include those at very low altitudes, where the atmosphere is source of aerodynamic drag on the spacecraft. To extend the lifetime of such missions, an efficient propulsion system is required. One solution is Atmosphere-Breathing Electric Propulsion (ABEP) that collects atmospheric particles to be used as propellant for an electric thruster. The system would minimize the requirement of limited propellant availability and can also be applied to any planetary body with atmosphere, enabling new missions at low altitude ranges for longer times. IRS is developing, within the H2020 DISCOVERER project, an intake and a thruster for an ABEP system. The article describes the design and simulation of the intake, optimized to feed the radio frequency (RF) Helicon-based plasma thruster developed at IRS. The article deals in particular with the design of intakes based on diffuse and specular reflecting materials, which are analysed by the PICLas DSMC-PIC tool. Orbital altitudes and the respective species based on the NRLMSISE-00 model (O, , , He, Ar, H, N) are investigated for several concepts based on fully diffuse and specular scattering, including hybrid designs. The major focus has been on the intake efficiency defined as , with the incoming particle flux, and the one collected by the intake. Finally, two concepts are selected and presented providing the best expected performance for the operation with the selected thruster. The first one is based on fully diffuse accommodation yielding to and the second one based on fully specular accommodation yielding to . Finally, also the influence of misalignment with the flow is analysed, highlighting a strong dependence of in the diffuse-based intake while, for the specular-based intake, this is much lower finally leading to a more resilient design while also relaxing requirements of pointing accuracy for the spacecraft., Article signat per 32 autors/es: F. Romano, J. Espinosa-Orozco, M. Pfeiffer, G. Herdrich, N.H. Crisp, P.C.E. Roberts, B.E.A. Holmes, S. Edmondson, S. Haigh, S. Livadiotti, A. Macario-Rojas, V.T.A. Oiko, L.A. Sinpetru, K. Smith, J. Becedas, V. Sulliotti-Linner, M. Bisgaard, S. Christensen, V. Hanessian, T. Kauffman Jensen, J. Nielsen, Y.-A. Chan, S. Fasoulas, C. Traub, D. García-Almiñana, S. Rodríguez-Donaire, M. Sureda, D. Kataria, B. Belkouchi, A. Conte, S. Seminari, R. Villain., Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

This study talks about the process of integration and verification of a nanosatellite, the 3CAT-4, developed in the NanoSat Lab laboratory in the UPC. In the study the latest refurbishments of the satellite have been introduced, changes that lead to a series of structural analisis tests of every subsystem to qualify them, and finally to integrate a replica of the entire satellite to which a study of the vibrations profile has been made in preparation for the future launch.

En aquesta tesis, es realitza un estudi físic dels magnetorquers per tal de controlar l'actitud de nanosatèl·lits CubeSat en òrbita terrestre baixa. S'estudia el camp magnètic terrestre en algunes òrbites terrestres baixes. Es dissenyen alguns magnetorquers amb els paràmetres físics requerits. Finalment, es realitzen algunes simulacions teòriques i pràctiques referents a la orientació d'un CubeSat orbitant en les òrbites estudiades en el qual la seva orientació és controlada a través dels magnetorquers prèviament dissenyats., En esta tesis, se realiza un estudio físico de los magnetorquers para controlar la actitud de nanosatélites CubeSat en órbita terrestre baja. Se estudia el campo magnético terrestre en algunas órbitas bajas. Se diseñan algunos magnetorquers con los parámetros físicos requeridos. Finalmente, se realizan algunas simulaciones teóricas y prácticas referentes a la orientación de un CubeSat orbitando en las órbitas estudiadas en el cual su orientación es controlada mediante los magnetorquers previamente diseñados., In this thesis, a physical study of magnetorquers for attitude control of CubeSat nanosatellites at low Earth orbit is developed. Earth's magnetic field at low Earth orbit is studied. Some magnetorquers are designed according to the required physical parameters. Finally, some theoretical and practical simulations related to the orientation of a CubeSat orbiting at the studied orbits and controlled (in terms of orientation) by the designed magnetorquers are done.

The use of very low Earth orbits (VLEO), for communications and remote sensing satellites, offers a number of significant payload and platform benefits. Imaging from these altitudes allows higher resolution or smaller optical payloads, whilst radar also benefits from improved link budgets leading to smaller antennas and lower transmission power. Communications payloads also have improved link budgets, reduced latency, and improved frequency reuse factors. Platform benefits include a more benign radiation environment, lower cost per kilogram to launch satellites, and atmospheric drag makes the environment inherently sustainable, simultaneously removing debris objects and ensuring satellites are quickly removed from orbit at the end of their operational lives. However, the impact of drag on satellite and mission operations must also be addressed. The DISCOVERER project, which commenced in 2017, is addressing the following key questions about technologies that would enable the commercially viable and sustained operation of satellites in VLEO: 1. Are there materials or processes which reduce the induced drag on spacecraft surfaces? 2. Are there propulsion methods which use the residual atmospheric gas as a propellant, providing drag compensation whilst removing the lifetime limits caused by carrying a limited amount of propellant? 3. How can we improve our understanding of, and make best use of, the orbital aerodynamics of a space platform and its ability to perform attitude control manoeuvres? 4. And what are the new opportunities that these technologies may bring to the market? This paper provides highlights from the developments made during the DISCOVERER project to date, demonstrating the potential for a new, commercially attractive, class of aerodynamic satellites operating in VLEO., Article signat per 30 autors: Peter C.E. Roberts, Nicholas H. Crisp, Vitor T.A. Oiko, Steve Edmondson, Francesco Romano, Silvia Rodriguez-Donaire, Daniel Garcia-Almiñana, Sarah J. Haigh, Brandon E.A. Holmes, Sabrina Livadiotti, Alejandro Macario-Rojas, Katharine L. Smith, Luciana A. Sinpetru, Jonathan Becedas, Valeria Sulliotti-Linner, Simon Christensen, Thomas K. Jensen, Jens Nielsen, Morten Bisgaard, Yung-An Chan, Georg H. Herdrich, Stefanos Fasoulas, Constantin Traub, Miquel Sureda, Dhiren Kataria, Badia Belkouchi, Alexis Conte, Simon Seminari, Rachel Villain, Ameli Schwalber., Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

Desde el comienzo de la era espacial, la filosofía de diseño de satélites estuvo dominada por diseños conservadores construidos con componentes altamente duraderos para soportar condiciones ambientales extremas. Durante las últimas dos décadas, la aparición de los CubeSats ha cambiado esta filosofía permitiendo todo un mundo de nuevas posibilidades. El despliegue de grandes constelaciones de CubeSats en órbita terrestre baja (LEO, en inglés) revolucionará el sector espacial al permitir ciclos de innovación más rápidos y económicos. Sin embargo, la confiabilidad de los CubeSats todavía se considera un obstáculo debido a las considerables tasas de fallo entre universidades y empresas, generalmente atribuidas a casos de pérdida completa de misión tras la eyección del desplegador orbital y al fallo de los subsistemas. Esta tesis se desarrolla en el marco del proyecto de investigación PLATHON, que pretende desarrollar una plataforma de emulación Hardware-in-the-loop para constelaciones de nanosatélites con comunicación óptica entre satélites y enlaces tierra-satélite. Un aspecto crucial de este proyecto es tener un propagador orbital suficientemente preciso con control de maniobras y representación gráfica en tiempo real. Los programas de propagadores disponibles se han analizado para seleccionar el sistema OpenSatKit de la NASA, una plataforma multifacética con un propagador incorporado conocido como 42. El propósito de esta disertación es analizar la viabilidad de implementación del programa para la creación de un banco de pruebas de constelaciones en comparación con un propagador previo desarrollado en MATLAB/Simulink. La documentación inicial es un enfoque de exploración para examinar las capacidades del 42 en distintos escenarios con objeto de adaptar el sistema PLATHON al funcionamiento interno y las limitaciones del programa. Las modificaciones y simulaciones del programa allanan el camino para el futuro desarrollo de la red interconectada PLATHON; específicamente, Since the beginning of the space age, satellite design philosophy was dominated by conservative designs built with highly reliable components to endure extreme environmental conditions. During the last two decades, the dawn of the CubeSats has changed this philosophy enabling a whole world of new possibilities. The deployment of monumental CubeSat constellations in low Earth orbit is set to revolutionise the space sector by enabling faster and economical innovation cycles. However, CubeSat reliability is still considered an obstacle due to the sizeable fail rates among universities and companies, generally attributed to the dead-on-arrival cases and subsystem malfunctions. This thesis is developed in the framework of the PLATHON research project that intends to develop a Hardware-in-the-loop emulation platform for nanosatellite constellations with optical inter-satellite communication and ground-to-satellite links. A crucial aspect of this project is to have a sufficiently precise orbital propagator with real-time manoeuvring control and graphical representation. The available propagator programmes are analysed to select NASA’s OpenSatKit, a multi-facet platform with an inbuilt propagator known as 42. The purpose of this dissertation is to analyse the implementation feasibility of the programme for the creation of a constellation testing bench compared to previously selfdeveloped propagators based on MATLAB/Simulink. The initial documentation is a scouting approach to examine 42’s capabilities under distinct scenarios to adapt the PLATHON system to the programme’s inner workings and constraints. The programme modifications and simulations pave the way for the future development of the interconnected PLATHON network; specifically, the inter-process communication capabilities have been tested to imitate the inputs of spacecraft attitude control systems through bidirectional socket interfaces.

Aquest treball presenta l'estudi numèric de viabilitat de l'arquitectura de missió proposada per l'equip 4DCube de l'IEEC per a monitorització in situ de fragments petits de brossa espacial (<10 cm) des de nanosatèl·lits. L'estudi ha desenvolupat una simulació de l'òrbita dels satèl·lits juntament amb les d'una població generada de vora 700k objectes, i ha conclòs que el nombre esperat de deteccions és de l'ordre de 100k a l'any. La població s'ha generat per a ajustar-se a les estimacions de densitat d'objectes d'entre 1 i 10 cm segons el model MASTER de l'ESA, i l'algoritme de generació ha estat discutit i confirmat amb enginyers de l'Oficina de Brossa Espacial de la mateixa agència. La simulació ha estat escrita en llenguatge C utilitzant OpenMPI per a permetre'n la paral·lelització, i ha estat executada en un clúster de 32 nuclis de l'ICCUB. Els resultats suggereixen que, considerant la incertesa deguda a la tècnica de la paral·laxi, una determinació d'òrbita preliminar precisa és viable, almenys, per a alguns milers d'objectes a l'any. En aquest sentit, s'ha proposat una generalització del mètode de Herrick-Gibbs, per a determinació d'òrbita preliminar amb qualsevol conjunt de 2n+1 observacions, i els resultats suggereixen que podria ser un ordre més precís que el promitjat de les formulacions clàssiques dels mètodes de Herrick-Gibbs i de Lambert-Gauss respecte el nombre d'observacions consecutives. A més a més, algunes tècniques senzilles de classificació basades en Machine Learning com l'algoritme KNN permeten predir la precisió esperada en la determinació d'òrbites amb taxes d'encert superiors al 95%., This thesis presents the numerical feasibility study of the mission architecture proposed by IEEC's 4DCube team for small space debris (<10 cm) in-situ monitoring from nanosatellites. The study has developed a simulation of the satellites' orbits together with a generated population of 700k debris objects, and concluded that the number of annual detections is expected to be in the order of 100k objects. The population has been generated to be compliant with the density estimations of debris in the 1-10 cm size range according to ESA's MASTER model, and the generation algorithm has been discussed with and confirmed by ESA's Space Debris Office engineers. The simulation has been written in C language using OpenMPI to allow parallelisation, and run in a 32-core cluster at ICCUB. The results suggest that, after considering the uncertainty due to the parallax technique, accurate preliminary orbit determination would be feasible for a few thousand objects per year. In this regard, a generalisation of the Herrick-Gibbs method for preliminary orbit determination valid for any set of 2n+1 observations has been proposed, and the results suggest that it may be accurate by a greater order of magnitude than the averaged classical formulation of the Herrick-Gibbs and Lambert-Gauss methods with respect to the number of consecutive observations. Also, simple classification techniques based on Machine Learning such as the KNN algorithm are able to predict the expected accuracy in the orbit determination with the only information of the observation parameters, with accuracies over 95%.

This project covers the entire design, construction, and release of a software artifact written in Python, which features a graphical user interface, and a MATLAB astrodynamics core. The software is to be used on mission design tasks, mainly focused on sustained human interplanetary mission design.

Today, our calling to explore the universe is even greater than fifty years ago, this calls out for a new design in our propulsion systems in order to achieve a sustainable, reusable and Earth-conditions independent. Sixty years ago, the worldwide known as the space race started. The first step on the Moon by a Homo Sapiens Sapiens was the end point on that race and unfortunately the end of the interest in the conquest of space and space exploration, until now. Humankind finds thyself again in the verge of a new space race, now to make ourselves multi-planetary species, setting foot on Mars in the next decade. So far, the journey has been challenging and full of technology advancements, however, in order to avoid another half century of human space inactivity rather than the ISS, new advancements need to be done. The urge to re-conquer the Moon and settle there a human base will be key for the global economy of the country that achieves that goal and will be the beginning of a new space era. In the next decades, the rise of interest in the cosmic bodies that surround Earth will be exponential due to the resources those provide and the constant quenching of Earth resources; thus, the era of cosmic bodies exploitation of materials and human settlements will start if not already started. The figure below shows the known space missions along the decades and it can be observed the continuous increment of missions along the years and it will keep increasing in the following decades. However, in order to let this new space episode start, the most pressing needs of the old space episode need to be tackled. That is why, throughout this master’s thesis, it is aimed to achieve a first approach on the future of in-situ resources utilization propulsion systems, with the final goal of designing and testing a functional propulsion system that would match the requirements settled; paving the way to a thorough research on alternative rockets independent from the resources of Earth a

The Satellite for Orbital Aerodynamics Research (SOAR) is a CubeSat mission, due to be launched in 2021, to investigate the interaction between different materials and the atmospheric flow regime in very low Earth orbits (VLEO). Improving knowledge of the gas–surface interactions at these altitudes and identification of novel materials that can minimise drag or improve aerodynamic control are important for the design of future spacecraft that can operate in lower altitude orbits. Such satellites may be smaller and cheaper to develop or can provide improved Earth observation data or communications link-budgets and latency. In order to achieve these objectives, SOAR features two payloads: (i) a set of steerable fins which provide the ability to expose different materials or surface finishes to the oncoming flow with varying angle of incidence whilst also providing variable geometry to investigate aerostability and aerodynamic control; and (ii) an ion and neutral mass spectrometer with time-of-flight capability which enables accurate measurement of the in-situ flow composition, density, velocity. Using precise orbit and attitude determination information and the measured atmospheric flow characteristics the forces and torques experienced by the satellite in orbit can be studied and estimates of the aerodynamic coefficients calculated. This paper presents the scientific concept and design of the SOAR mission. The methodology for recovery of the aerodynamic coefficients from the measured orbit, attitude, and in-situ atmospheric data using a least-squares orbit determination and free-parameter fitting process is described and the experimental uncertainty of the resolved aerodynamic coefficients is estimated. The presented results indicate that the combination of the satellite design and experimental methodology are capable of clearly illustrating the variation of drag and lift coefficient for differing surface incidence angle. The lowest uncertainties for the drag coeffic, Peer Reviewed, Postprint (author's final draft)

CubeSats have revolutionized Earth Observation and space science, although their small size severely restricts satellite performance and payload. Antenna deployment from a stowed configuration in these small-satellites remains a great challenge. This paper presents the design, optimization, and testing of an L-band helix antenna deployment system for the 3 Cat-4, a 1U CubeSat developed at the NanoSat Lab (UPC). The 506-mm-long antenna is packed into a 26.8 mm gap together with a tip mass that provides a gravity gradient for nadir-pointing. The 3 Cat-4 Nadir Antenna Deployment Subsystem (NADS) melts dyneema strings to release the antenna in successive steps. PTFE coated fiberglass ensures the helix’s nominal diameter and pitch while a security locking mechanism serves as a redundant system for holding it in place before deploying. Our novel methodology optimizes the number and length of the NADS deployment steps. A slow-motion camera and image recognition software track the velocity and acceleration of the antenna sections by means of tracking dots. Kinematic analysis of the antenna resulted in a final design of four length steps: 90, 300, 420 and 506 mm. Our methodology for calculating these values can be widely applied for measuring many deployment system’s kinematic properties. The NADS performance is tested by characterizing antenna rigidity, analyzing helix behavior after one year in stowed configuration, and by testing the deployment mechanism in a thermal vacuum chamber at -35°C, the most critical temperature stress scenario. All test results are satisfactory. The final design of the NADS deployment mechanism is light, stable, reliable, affordable, highly scalable, and can be used in many antenna configurations and geometries. The 3 Cat-4 mission was selected by the ESA Academy to be launched in Q4 2021., Postprint (published version)

El proyecto se basa en realizar un software en MATLAB, u otra plataforma a determinar, que integre un simulador de órbitas, que ya se ha desarrollado en un proyecto anterior, en una plataforma de cubesats en el laboratorio, que se van a enviar datos entre ellos. La plataforma consta de un conjunto de nanosatélites en forma de cubo de 1x1x1 dm de dimensión (cubesat). Además de los datos entre cubesats, cada uno enviará, mediante bluetooth, información on-line del consumo de baterías, ángulo de inclinación y estado de la comunicación con otro cubesat. El simulador presentará en pantalla la posición de los cubesats en función de los datos de lanzamiento (simulados) y el tiempo transcurrido desde el mismo. También girará los cubesats según el ángulo real que tenga, en coordenadas terrestres, cada cubesat de la plataforma del laboratorio. Este ángulo se obtiene mediante subsistemas ya desarrollados con anterioridad a este proyecto. También mostrará datos de carga de batería y de consumo en el acto de comunicación de datos, que se obtendrán del subsistema de potencia que se diseña en otro proyecto.

Challenging space missions include those at very low altitudes, where the atmosphere is source of aerodynamicdrag on the spacecraft. To extend such missions lifetime, an efficient propulsion system is required. Onesolution is Atmosphere-Breathing Electric Propulsion (ABEP). It collects atmospheric particles to be usedas propellant for an electric thruster. The system would minimize the requirement of limited propellantavailability and can also be applied to any planet with atmosphere, enabling new mission at low altituderanges for longer times. Challenging is also the presence of reactive chemical species, such as atomic oxygenin Earth orbit. Such species cause erosion of (not only) propulsion system components, i.e. acceleration grids,electrodes, and discharge channels of conventional EP systems. IRS is developing within the DISCOVERERproject, an intake and a thruster for an ABEP system. The paper describes the design and implementationof the RF helicon-based inductive plasma thruster (IPT). This paper deals in particular with the design andimplementation of a novel antenna called the birdcage antenna, a device well known in magnetic resonanceimaging (MRI), and also lately employed for helicon-wave based plasma sources in fusion research. This isaided by the numerical tool XFdtd®. The IPT is based on RF electrodeless operation aided by an externallyapplied static magnetic field. The IPT is composed by an antenna, a discharge channel, a movable injector,and a solenoid. By changing the operational parameters along with the novel antenna design, the aim is tominimize losses in the RF circuit, and accelerate a quasi-neutral plasma plume. This is also to be aided by theformation of helicon waves within the plasma that are to improve the overall efficiency and achieve higherexhaust velocities. Finally, the designed IPT with a particular focus on the birdcage antenna design procedureis presented, This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 737183, Peer Reviewed, Postprint (author's final draft)

The AOCS is the system needed in order to know the orientation of our space vehicle and be able to control it so it is possible to reach the desired pointing and given this, began with the execution of scientific missions. In the case of this project the AOCS system will be only consists of a gravity boom, so the attitude control of this 3U CubeSat will be passive trough the gravity gradient torque. For the simulations that take place in this study, the software MATLAB will be used as a vehicle to analyse the AOCS system. This same software will allow to determine the inertia and other characteristics of the 3U Cubesat, which will be fundamental to the subsequent calculations in order to obtain the gravity boom influence in the spacecraft stabilization. This document will explain the physics behind the spacecraft model, the calculations needed in order to obtain its inertia values and also the equations needed to model the space environment and the forces that are needed for the chosen analysis. Also the algorithms designed in MatLab will be presented in form of Annex, being the calculations for the plots, inertia, angular deviations, ... The results have the goal of determining if the use of the gravity boom is enough to control the attitude of the Cubesat, so diverse configurations for the satellite will be simulated, with variations on the mass of the gravity boom and the length of the cable that links it with the CubeSat body. As it shows in the conclusion section, the configuration where mgb= 1 kg and lcb= 2.5 m seems to meets the requirements of pointing for medium/low accuracy, but if the use of some sensor was to be considered (such as sun sensor or star trackers), missions with the need for a high accuracy system could be feasible as the nadir pointing obtained has a very low angular deviation. However, even though the results for this values are successful, any increase in both variables characterstics lead to the instability of the CubeSat and can not be

The DISCOVERER project is developing technologies to enable commercially-viablesustained-operation of satellites in very low Earth orbitsfor communications and remote sensing applications. Operatingcloser to the surface of the Earthsignificantly reduceslatency for communications applications and improves link budgets, whilstremote sensing also benefitsfrom improved link budgets,the ability to havehigher resolution or smaller instruments, all of which providecost benefits. In addition, all applications benefit from increased launch mass to lower altitudes, whilst end-of-life removal is ensured due to the increased atmospheric drag. However, this drag must also be minimised and compensated for. DISCOVERER is developing several critical technologies to enable commercially-viable operations in at these lower altitudesincluding aerodynamic materials, aerodynamic attitude and orbitcontrol methods, atmosphere breathing electric propulsion and an in-situenvironment monitoring payload. Thecurrentstatus of these developments are summarised, along with the plans for thecoming year., The DISCOVERER project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 737183., Postprint (published version)