Aerotecnica Missili & Spazio最新文献

Micrometric dust particles of lunar regolith represent one of the most serious issues of the harsh Moon environment. Indeed, the extremely high vacuum conditions expose the lunar soil minerals to intense ultraviolet and galactic cosmic rays’ bombardment during the Moon’s daylight producing photoionization of the constituent’s atoms and electron release. Moreover, the Moon periodically interacts with the surrounding solar wind which generates a continuous flux of charged particles accompanied by electric fields around the terminator region able to lift off the lunar regolith dust up to ~100 km above the geometrical surface. In this way, micrometric granular matter forms a subtle veil of contaminants. This electrically charged and extremely adhering dust environment not only can cause various critical drawbacks to several robotic parts, e.g., mechanical components, electronic devices, solar panels, thermal radiators, rover seals and bearings, etc. but also can dramatically damage the respiratory systems of humans if accidentally inhaled. For these reasons, lunar dust was recognized, by several agencies including NASA and ESA, as one of the main hazards for the ongoing robotic and manned exploration and colonization of our natural satellite. To overcome or at least mitigate these issues, several technologies were developed and assessed ranging from the active ones requiring a source of energy, e.g., mechanical, fluidal, and, above all, electric devices, to the passive technologies involving suitable material design and development. The work here reported presents several possible active and passive chemical and physical strategies for protecting sensitive surfaces of space systems against granular contamination. This paper is intended as a survey of dust mitigation issues and technical mitigation with the approach pursued by the Italian Aerospace Research Centre (CIRA) related to a hybrid technique with an innovative material. The strategy that is under implementation by CIRA is based on the combination of active and passive techniques and consists of the design and development of innovative high-performance polymers exhibiting simultaneously outstanding thermo-mechanical properties and superior non-sticking capacity, i.e., abhesion.

In recent years, the field of Unmanned Aerial Vehicles has shown great technological progress, and many new applications were born. To assess the potential of this technology and to improve the availability and reliability of the rising services it is critical to overcome operational limitations. One key operational hazard is atmospheric in-flight icing, resulting in large aerodynamic penalties, unbalances and other detrimental phenomena that can sometimes lead to catastrophic consequences. In this paper, a new ice tunnel developed in the large hypobaric and climatic chamber of the terraXcube facility of Eurac will be presented. Following a preliminary characterization of the nozzles employed in the tunnel by shadowgraphy at the Free University of Bolzano, a characterization and calibration of the spray system has been performed following the EASA regulation reported in the Easy Access Rules for Large Rotorcraft (CS-29).

In the current global context, where the issue of climate change has gained significant prominence, the ATEMO (Aerospace Technologies for Earth Monitoring and Observation) project introduces an innovative and scalable platform capable of measuring multiple environmental factors, including air pollution, light pollution, and vegetation analysis. This versatile platform can be seamlessly integrated onto various aerial vehicles, such as drones, stratospheric balloons, and tethered balloons. Its primary goal is to establish a comprehensive framework for environmental analysis on multiple fronts, while also contributing valuable data to the scientific literature. Furthermore, it offers a cost-effective alternative with enhanced spatial and temporal resolution for ground-based comparisons. During the initial year of research, ATEMO project focused on amalgamating the technological expertise of the research group into a single device. This device facilitated ground-based light source observations, multi-spectral vegetation analysis, and air quality assessments. The first test campaign, carried out during the summer of 2023, was aimed at estimating vegetation indices and comparing them over time with satellite-derived data. This article provides insights into the current configuration of ATEMO, outlines the testing procedures, and presents the preliminary findings.

Advanced avionics and automation technologies have significantly transformed cockpit operations, resulting in a gradual reduction of the crew members on-board. Single-pilot operations (SPO) concept is gaining significant attention in the aviation industry due to its potential for cost savings and to cope with the anticipated pilot shortage and the increasing air traffic demand. This paper conducts a scoping literature review on SPOs, serving as an initial step to map the scientific peer-reviewed content on the subject. The survey focuses on three thematic domains, which are, respectively, operations, automation, and the emerging field of digital and cognitive flight assistants. The methodology involved the use of Google Scholar and IEEE Xplore databases. Sources were selected adapting the search criteria to the proposed sub-topics and prioritizing either the most cited and recent contributions. The analysis of the literature reveals a growing body of work in the recent years. This review also highlights interest in the human-centered design for automation solutions which are responsive to cognitive and behavioral states of the pilot. While acknowledging the potential safety and operational challenges associated with SPOs and the pilot-automation cooperation, this work suggests that great research efforts should be made on the human factor and regulatory subjects to pave the way for a feasible and safe implementation of the single-pilot paradigm in commercial aviation.

Due to their simplicity and relative ease of manufacture, single-stage centrifugal and mixed flow micro gas turbine (MGT) engines are preferred in thrust-based remotely piloted aerial vehicles. A single-stage mixed-flow compressor upgrade for the 200 N CAT250TJ MGT engine is numerically evaluated and presented. An in-house developed mean line application and commercial CFD software is used for the design and performance evaluation of the proposed upgrade configurations. The CAT250TJ – Gen1 engine features a single-stage centrifugal compressor, annular combustor, and single stage axial turbine. Apart from an upgraded impeller, a new crossover diffuser configuration is introduced to replace the wedge-type, straight outlet diffuser configuration of the Gen1 engine. The new single vane crossover diffuser configuration provides a design point total-to-total efficiency and pressure ratio increase of 8.3% and 12.1%, respectively. A disadvantage of a single-vaned crossover diffuser compared to legacy diffusers is a narrower operating range. To alleviate this issue, various combinations of tandem and splitter vane crossover diffuser configurations are proposed. These provide an enhanced operating range, comparable with the operating range displayed by the Gen1 configuration. A turbine power matching analysis is additionally completed to ensure proper compressor integration. Gas turbine cycle software is used to evaluate the on-engine performance of the upgraded compressor configurations. It is shown that the new baseline, single vane crossover diffuser configuration provides a 10.74% increase in design point static thrust.

In this paper, the problem of guiding a vehicle from the entry interface to the ground is addressed. The Space Shuttle Orbiter is assumed as the reference vehicle and its aerodynamics data are interpolated to properly simulate its dynamics. The transatmospheric guidance is based on an open-loop optimal strategy which minimizes the total heat input absorbed by the vehicle while satisfying all the constraints. Instead, the terminal phase guidance is achieved through a multiple-sliding-surface technique, which is able to drive the vehicle toward a specified landing point with desired heading angle and vertical velocity at touchdown, even in the presence of nonnominal initial conditions. The terminal guidance strategy is successfully tested through a Monte Carlo campaign, in the presence of stochastic winds and wide dispersions on the initial conditions at the terminal area energy management, in more critical scenarios with respect to the orbiter safety criteria.

Stellar in-flight calibrations have a relevant impact on the capability of space optical instruments, such as telescopes or cameras, to provide reliable scientific products, i.e., accurately calibrated data. Indeed, by using the in-flight star images, instrument optical performance can be checked and compared with the on-ground measurements. The analysis of star images carried out throughout the entire lifetime of the instrument in space will enable tracking changes in instrument performance and sensitivity due to degradation or misalignment of the optical components. In this paper, we present the concept, the necessary input and the available outputs of the simulations performed to predict the stars visible in the field of view (FoV) of a specific space instrument. As an example of the method, its application to two specific cases, the Metis coronagraph onboard Solar Orbiter and the stereo camera STereo Channel (STC) onboard BepiColombo, are given. Due to their proximity to the Sun, and to Mercury for STC, both instruments operate under harsh environmental conditions in terms of radiation exposure ((e.g., cosmic rays and SEP), high temperatures and significant temperature variations. Therefore, it is crucial to monitor their optical performances.

In the last few years, the number of orbiting satellites has increased exponentially, in particular due to the development of the New Space Economy. Even if this phenomenon makes the space more accessible, bringing a great contribution to the scientific, economic and technological fields, on the other hand it contributes to the overpopulation of the space background. Therefore, it is necessary to develop new techniques to manage the space environment, such as in orbit servicing, which is a procedure that aims to refuel and repair satellites to extend their operational life. A first step to reach this goal is to inspect closely the object of interest to study its features. In this framework, the Space Rider Observer Cube (SROC) mission is being developed. SROC is a payload that will be deployed by Space Rider (SR), an uncrewed and reusable robotic spacecraft designed by ESA (European Space Agency). SROC is a 12U CubeSat, whose goal is to carry out inspection manoeuvres around SR, then re-enter on board using a safe docking system to come back to Earth. The feasibility of a mission similar to SROC has been simulated during a university class, starting from the definition of the system requirements with particular focus on the analysis of the payloads and subsystems, to ensure the achievement of the mission goals. In particular, the CubeSat is equipped with an imaging payload to capture high resolution images of Space Rider surface and a docking mechanism. Then, the design of the orbit and the simulation of the effects of the space environment on the CubeSat have been studied using GMAT, SYSTEMA, MATLAB and other numerical tools. The results of the study are useful for future missions, aiming to inspect orbiting objects, such as operative satellites for in orbit servicing, space debris and dead satellites to study their geometries and plan their removal.

The utilization of liquid oxygen/liquid methane couple ((LOX/LCH_4)) as a potential candidate to substitute hypergolic propellants and hydrazine in the next future propulsion systems has arisen an increasing interest due to the advantages offered in terms of low environmental impact, re-usability, cooling capabilities and relatively high specific impulse (Schuff et al. in Integrated modeling and analysis for a lox/methane expander cycle engine: Focusing on regenerative cooling jacket design, p. 4534, 2006 ). In this perspective, the Italian Aerospace Research Center manages the “HYPROB” research program, cofunded by the Italian Research and University Ministry, that has the objective to improve the national capabilities into developing engines, fed by hydrocarbons, that could be successfully applied as propulsion units for third stages of launchers for space exploration. The “HYPROB” program led to the realization of a (LOX/LCH_4) engine named “DEMO-0A”, a 30 kN thrust class demonstrator, technologically representative of a regenerative thrust chamber assembly of an expander engine (Ricci et al. in Energies, p. 2190, 2022). The present paper describes the results of the numerical simulations performed by means of the EcosimPro software, aimed at reproducing the operative conditions, both cold flow and firing, of the regenerative thrust chamber “DEMO-0A”. An assessment of the capabilities of the software in predicting the behaviour of the demonstrator by modelling it with a 1-D approach and by considering different wall heat exchange semiempirical correlations has been done by comparing numerical results and the available experimental data gathered during both cold flow both firing test campaigns.