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In 2021, the Space Systems Laboratory of the University of Pisa (UniPi) started a student-oriented high-altitude ballooning programme intended to provide an opportunity for hands-on experience in support of the teaching of scientific and technical courses. The programme provides mentoring on scientific, technical and management issues, along with financial support and assistance with integration and launch on a sounding balloon platform. The goal is to conduct flying experiments in the stratosphere, retrieve them after landing and process the results; by doing so, the students experience all phases of a scientific mission project, from conceptual design to realisation, operations and post-flight analysis. Following a call for proposal open to all students of the UniPi across all study areas, three experiments were selected featuring multidisciplinary teams. This paper summarises the features of the programme’s first edition and presents the main lessons learned.

Prospecting is a necessary pre-requisite of future asteroid mining ventures. It is generally assumed that inspection for the purpose of identifying the asteroid composition can be effectively accomplished from a distance through remote sensing. To be carried out in a timely and economically viable way, prospecting is best performed by devising trajectories such that a single spacecraft manages to fly by as many asteroid as possible, yet seeking to minimize a cost function that we assume to be coincident with propellant consumption. In this paper, we present a method to identify trajectory sequences to multiple asteroids. We restrict our analysis to Near-Earth Asteroids (NEAs), i.e.,, those with perihelion at less than 1.3 AU from the Sun, focusing on Apollo class NEAs only. The volume of space where encounter seeking takes place is a torus-shaped 3-D region in the proximity of the ecliptic. Under the assumption of using impulsive maneuvers to connect ballistic coast arcs, we show that a deterministic building blocks approach is successful in finding a significant number of multi-flyby mission profiles with the desired characteristics. Using this scheme, it is possible to envisage realistic asteroid prospecting missions using a single launch to deploy a number of small spacecraft, with tens—or possibly hundreds—of asteroids visited in a few years.

Asteroid mining is one of the most promising private space ventures of the near future. Near-Earth Asteroids (NEAs), i.e. those with perihelion at less than 1.3 AU from the Sun, are among the best candidates for such venture. In preparation of mining expeditions, it is likely that prospector missions will be carried out well in advance so to assess the accessibility, potential for revenues and possible critical issues of target asteroids. This work is concerned with the problem of the feasibility of a single spacecraft prospector mission capable of visiting as many NEAs as possible in one shot, focusing on Apollo-class asteroids only. The search of possible trajectories is done assuming a chemically propelled spacecraft with realistic specific impulse and propellant mass ratio, so to allow for a credible mission design with a reasonable, cost-effective total duration. In order to restrict the number of possible trajectories, only those that lie in the plane of the ecliptic are examined; such trajectories can be reached from the Earth without expensive plane change maneuvers. The search for a maximum number of encounters is thus restricted to those occurring where the asteroid orbit crosses the ecliptic. A deterministic building blocks approach is adopted, dividing the optimization problem in two parts: a local optimization for possible target determination; and a global optimization for the choice of the overall trajectory. It is found that the combined approach leads to the identification of viable trajectories, able to perform a number of encounters that depends on the launch epoch; as an example, in one test case two different sets of 21 NEA’s each were identified that could be reached with a single launch, with a slightly different propellant expenditure. It is concluded that the method is well suited to perform feasibility studies of NEA missions with good accuracy and moderate computational cost.

The paper presents the evolution and trends in the Master’s-level studies in aerospace engineering in Italy, looking at the past 20 years. In the year 2000, a major reform of the higher education in engineering took place in Italy, with the introduction of the so-called ‘Bologna system’ and the clear separation of Bachelor’s and Master’s degree studies. With this reform, a relatively high flexibility was given to universities to define their programme structures. The ministerial rules defined only broad subject areas within which courses and credits should be allocated. This reform allowed the diversification of the educational profile within each university and, even more relevant, allowed the creation of mobility across the country between Bachelor’s and Master’s study programmes. The paper will show the basic facts and figures in the six Italian universities participating in the Partnership of a European Group of Aeronautics and Space UniversitieS (PEGASUS) network (Politecnico di Milano, Politecnico di Torino, Università di Pisa, Università degli Studi di Napoli ‘Federico II’, Sapienza Università di Roma and Alma Mater Studiorum – Università di Bologna), elaborating on the impact of the potential workforce for the sector. Data have been collected from the official open data repository of the Italian Ministry of University, supplemented by information provided by the six universities under analysis. The comparative analysis shows two major results: the positive impact of the reform on the overall Italian higher education and, specifically, a greater appreciation of the aerospace curricula proposed in accordance with the new system.

Traditionally, the overlap between electronics and aerospace technology was limited to avionics, radars, satellites, and telecommunications. Sensors networks are emerging as an additional area of relevant interaction. In fact, in addition to the classical paradigm in which on-board sensors improve the navigation and control of aerial vehicles, e.g., in the fly-by-wire context, novel paradigms of cooperation between fixed networks of ground sensors and airborne ones are emerging today, especially for monitoring the environment. In this paper, we review current development trends and open challenges with reference to practical examples. We focus on the role of sensor miniaturization, energy harvesting, energy-aware communication architectures, and data fusion. Multidisciplinary development teams, with expertise spanning from microelectronics and data analysis, to operation of UAV swarms are expected to be necessary to address these challenges.

Sounding balloons have proven to be a very effective low-cost method to bring scientific and commercial payloads to the near-space environment. In the frame of our ongoing effort towards the development of a small stratospheric platform with autonomous flying capabilities, we have undertaken the design and manufacture of a flight experiment to verify the possibility to perform onboard attitude determination using the solar cell power output measurements to complement the inertial sensor. The system is based on six low-cost terrestrial solar cells placed on the sides of a box-shaped gondola, lifted to about 34 km altitude by a weather balloon. We describe the system architecture, the results of the first experimental flight and the post-landing attitude reconstruction.

The importance of earth observation (EO) from space is felt today more than ever in many different fields of human activity. Governments, international organizations, military bodies, private industry, and even individuals benefit every day of the products of spaceborne remote sensing technology. In this paper, we present a brief overview of some of the main trends in the EO scenario, focusing on the emergence of a new paradigm for EO space systems namely: the ongoing, disruptive shift from large satellites to constellations of small spacecraft, fueled by the recent introduction of several key technologies, such as for instance electric propulsion. We present the outline of a tool specifically conceived to assist the system architect in the early design phase of an EO constellation of microsatellites equipped with electric thrusters. A case study is presented for the application of a multisegmented constellation, with visual, thermal infrared, and radar components to remotely monitor a national railway network. We conclude that, in spite of the complexity of modern small satellite constellations, preliminary design can be successfully performed in a simplified and effective way.

The goal of this study is to design a dedicated, low cost satellite mission for environmental monitoring of the Amazon basin. The mission design is based on the unique characteristics of the small Brazilian launcher VLM-1. Launched from the near-equatorial Alcantara Launch Center, the vehicle allows for direct injection of about 150 kg in equatorial LEO, a low Earth orbit with zero (or near-zero) inclination. Such orbital configuration, actually used very seldom because of its limited ground coverage (restricted to equatorial regions only), proves to be ideal for near-continuous monitoring of the Amazon region. We present a possible microsatellite constellation that allows for high quality multispectral imaging of the Amazon basin with near-continuous coverage.

The recent explosion in proposed microsatellite missions is based on the possibility to mass-produce cheap platforms capable to deliver acceptable performance over a limited lifetime. The assumption behind such scheme is that individual microsatellites are expected/allowed to fail in reasonable numbers, the resulting degradation of constellation performance being limited due to the large population of active spacecraft. We argue that cheap platforms do not necessarily need to be seen as disposable assets, so that low cost constellations featuring a low number of microsatellites may nevertheless be capable of remarkable performance. The key technology needed to enable such feat is low power electric propulsion, whereby microsatellites are allowed to acquire and maintain precisely tuned orbital locations, compensate atmospheric drag to fly longer, and de-orbit safely at end of life. A number of such microsatellites may be fitted with an instrument each from a suite of different sensors operating in various spectral bands. The constellation would operate as an actively controlled system, with the individual instruments providing well coordinated raw data that may be processed using data fusion techniques to yield the final product. Starting from the proven performance of a currently available low power Hall thruster, we present general design criteria for constellations based on a 50 kg-class microsatellite bus. The potential benefits of such technology are outlined with respect to applications such as precision farming, urban area monitoring, and dual use land surveillance.

In March 2018, the first IEEE International Environmental Engineering Conference was held in Milan. The main goal of this event was to foster cross-disciplinary knowledge dissemination and innovation in environmental engineering and to promote a sustainable future for the environment. One of the special tracks was on Wireless Sensor Networks and Remote Sensing for Environmental Applications, including technologies, methodologies, systems, and applications for environmental engineering, specifically for monitoring and control of natural and artificial environments to ensure their livability and future sustainability as well as the well-being of individuals and the community. In the 2019 June volume, the first installment of the Special Issue on Wireless Sensor Networks and Remote Sensing for Environmental Applications has been issued. In this October volume, the second part of our special issue aims to collect and share with the wider IEEE AES Society other examples of emerging and innovative techniques based on the use of satellite and sensor network data for Earth observation and monitoring with the goal of protecting urban and not urban environment.

U-PHOS (Upgraded PHP Only for Space) is a project developed by a team of students from the University of Pisa with the goal to analyze and characterize the behavior of a Pulsating Heat Pipe (PHP), one of the most attractive two phases passive systems for thermal management in space applications. The PHP consists of a sealed serpentine capillary tube filled with a working fluid. The heat is efficiently transported by means of the combined action of phase change and capillary forces, so no extra equipment is required. The project aims at investigating the thermal response of such a device under a milli-gravity condition, in order to assess its effectiveness in space conditions. U-PHOS is one of the selected experiment of the REXUS/BEXUS programme, which allows European university students to carry out scientific and technical experiments on research rockets and balloons, thanks to a bilateral agency agreement between the German Aerospace Centre (DLR) and the Swedish National Space Board (SNSB) in collaboration with ESA. 19 students from the University of Pisa, with different backgrounds, compose the U-PHOS team. Students had the chance to completely design, build and test the experiment, which will flight up to space in March 2017. This paper intends to describe the work done by the students, their organization and how this experience empowered their careers, from both an academic and professional point of view.

With the entry into operation of the Sentinel-2 mission in June 2015, a new land monitoring costellation of twin satellites has been added to Copernicus project from ESA and new insights have been derived through the combination of Sentinel-2 data with other optical/multispectral data, and with other data from satellites belonging to the same Copernicus project. To this end, the objective of this paper has been to present new added-value tools first through the integration of different satellite platforms: data from NASA Landsat-8 and ESA Sentinel-1 have been used and combined, and furthermore through the comparison of satellite data all from the same Copernicus project: data from Sentinel-1 and Sentinel-2 have been jointly processed and compared. Although data from optical/multispectral sensors, as those of Landsat-8 and Sentinel-2, and data from SAR on board of Sentinel-1, are very different, their combination provides useful and interesting results. The integration and combination of these data can find useful application in many fields from oceans to waterways, from land surfaces to fossil deposits, from vegetation to forest areas. In this works authors have focused their interest in green areas and vegetation monitoring applications, by choosing as case of interest the Royal Palace of Caserta and its gardens. The idea has started from the increasing interest in monitoring the cultural heritage monuments and in particular the surrounding vegetation with the green areas and the parks inside. Satellite images can put into evidence boundaries modifications, the vegetation state, their possible degradation, and other phenomena such as changes in the territories due both to natural and to anthropogenic causes. Data combination from different sources as above specified gives a good number of indexes very useful to analyze the vegetation state and its health in a very deep way. Many of these indexes have been calculated and discussed for investigation.

Authors in this work aim to present new analysis methods for Earth Observation, developed by processing Sentinel-1 and Landsat-8 satellite data and combining them in an original way. Comparing SAR and Optical/Multispectral data is a procedure already in use because they are two acquisition systems that provide very different and therefore complementary and useful information. Even if the combination of such different data is not a simple process, the overall information greatly improves when both satellite data are jointly used, as application of our procedure to some case studies demonstrates.

A numerical model of the ion beam in field emission electric propulsion thrusters is presented. The objective of the study is to develop a computational tool capable of predicting the effects of thruster configuration parameters (geometry, voltage distribution between the electrodes) on thruster performance (beam divergence, ion exhaust velocity). A two-dimensional, steady model has been adopted. A simple emission model has been assumed, neglecting the detailed, microscopic description of the physical emission mechanism. The electric field is evaluated by a finite element scheme; boundary conditions are provided by an auxiliary technique based on the placement of fictitious charges in proximity to the electrode surfaces. The beam is simulated through a discrete number of charged particles; the effects of the associated space charge density distribution on the electric field is considered. The results of the simulations of typical thruster configurations are presented and discussed. The need to take space charge effects into account to attain a sufficiently accurate solution is indicated: the beam charge density modifies the electric potential distribution generated by the electrodes voltage difference, causing a decrease in the local electric field at emitter tip and an increase in beam divergence. Neutralization at a finite distance must be taken into account to fully appreciate the effects of different voltage distributions between the electrodes: a higher accelerator electrode voltage determines a lower ion exhaust velocity and a larger beam divergence. The capability of an additional, decelerating neutral electrode to focus the ion beam is also investigated, showing that only little improvement in beam containment is attained.

U-PHOS Project aims at analysing and characterising the behaviour of a large diameter Pulsating Heat Pipe (PHP) on board REXUS 22 sounding rocket. A PHP is a passive thermal control device where the heat is efficiently transported by means of the self-sustained oscillatory fluid motion driven by the phase change phenomena. Since, in milli-gravity conditions, buoyancy forces become less intense, the PHP diameter may be increased still maintaining the slug/plug typical flow pattern. Consequently, the PHP heat power capability may be increased too. U-PHOS aims at proving that a large diameter PHP effectively works in milli-g conditions by characterizing its thermal response during a sounding rocket flight. The actual PHP tube is made of aluminum (3 mm inner diameter, filled with FC-72), heated at the evaporator by a compact electrical resistance, cooled at the condenser by a Phase Change Material (PCM) embedded in a metallic foam. The tube wall temperatures are recorded by means of Fibre Bragg Grating (FBG) sensors; the local fluid pressure is acquired by means of a pressure transducer. The present work intends to report the actual status of the project, focusing in particular on the experiment improvements with respect to the previous campaign.

By replacing the liquid metal propellant with a ionic liquid, it is possible to develop a new, simplified FEEP system that combines most of the heritage and the advantages of the linear slit geometry with the easy of handling and operation of a more benign propellant. In view of the development of such Ionic Liquid FEEP thruster (IL-FEEP), an internal development activity is underway at Alta, aimed at the design and testing of an innovative linear slit thruster derived from the cesium experience. This paper presents the results of recent experimental campaigns aimed at assessing the performance of linear slit FEEP emitters fed with a ionic liquid propellant. For the first time, beam composition was evaluated using a time-of-flight mass spectrometry technique, allowing for a reliable estimate of the thruster’s specific impulse.

The Electric Solar Wind Sail (E-sail) is a novelpropulsion concept that enables faster space travel tomany solar system targets. E-sail uses charged solarwind particles as the source of its propulsion. This isachieved by deploying long, conducting and chargedtethers, which get pushed by the solar wind byCoulomb drag [1].E-sail technology is being developed to technicalreadiness level (TRL) 4-5 by the European Union’sSeventh Framework Programme for Research andTechnological Development, EU FP7, in a projectnamed ESAIL (http://www.electric-sailing.fi/fp7).Prototypes of the key parts are to be produced. Thedesign will be scalable so that a real solar winddemonstration mission could be scaled up from them.We review here the latest results of the constantlyevolving E-sail project.

A study supported by the European Space Agency (ESA), in the context of its General Studies Programme, performed an investigation of the possible use of space for studies in pure and applied plasma physics, in areas not traditionally covered by ‘space plasma physics’. A set of experiments have been identified that can potentially provide access to new phenomena and to allow advances in several fields of plasma science. These experiments concern phenomena on a spatial scale (101–104 m) intermediate between what is achievable on the ground and the usual solar system plasma observations. Detailed feasibility studies have been performed for three experiments: active magnetic experiments, largescale discharges and long tether–plasma interactions. The perspectives opened by these experiments are discussed for magnetic reconnection, instabilities, MHD turbulence, atomic excited states kinetics, weakly ionized plasmas,plasma diagnostics, artificial auroras and atmospheric studies. The discussion is also supported by results of numerical simulations and estimates.

Variable-specific-impulse electric propulsion systems can provide important advantages and cost reductions to any scale of planetary mission. The first part of this paper describes their potential benefits, with special emphasis on mission analysis aspects. The second part identifies the physical limitations of traditional electric propulsion technologies and presents some preliminary development results achieved within the frame of ongoing European activities.

This paper presents the design of a novel system for ion beam scanning. The system is equipped with a set of electrostatic probes mounted on a metallic frame that can be positioned in front of the thruster at controlled locations. The first results of experimental investigations made on a 100 micronewton FEEP emitter may suggest that the plume geometry is influenced by space charge effects at macroscopic distances from the thruster’s exit plane.