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Assessing the economic viability of new high-speed systems concepts since the early design phases is crucial for the success of future hypersonic vehicles including cruisers, reusable access-to-space and re-entry systems. Besides literature reports few parametric cost models for high-speed vehicles, all of them makes exclusively use of mass as parameter and none of the models moves beyond the vehicle level. This paper describes a new parametric cost estimation model which moves beyond the state-of-the-art methodologies (1) by integrating vehicle design and operational parameters (in addition to the mass) as cost drivers for the prediction of the vehicle life-cycle cost, (2) by introducing prediction margins accounting for the uncertainties on the data-driven correlations, (3) by providing a first estimate of the costs of every on-board subsystem, including combined cycle engines and multi-functional subsystems, (4) by increasing the granularity of the analysis up to technology level, thus providing a valuable support to Technology Roadmaping activities. The parametric cost estimation model has been refined and exploited in the context of the Horizon 2020 STRATOFLY project, where the technological, operational, environmental, and economic viability of a Mach 8 waverider concept have been investigated. • Innovative RDTE&PROD cost estimation methodology for civil high-speed vehicle. • New parametric equations using vehicle design and operational parameters as drivers. • Costs predictions at subsystems level including complex multi-functional subsystems. • Cost estimation as valuable support to technology roadmapping activities. • Technology Readiness Level as new cost driver for the RDTE cost of vehicles. [ABSTRACT FROM AUTHOR]

This paper discloses an innovative methodology for the generation and update of technology roadmaps to support strategic decisions for future hypersonic transportation systems, specifically targeting non-profit oriented R&D. The methodology is fully integrated into up-to-date conceptual design activity flows. It consists of five main steps that through mathematical and logical models moves from stakeholders' analysis up to planning definition and results evaluation. Complementary to the traditional experts-based methodologies, the rational process here presented allows for a well-structured logical definition of activities and/or missions required to enhance the readiness level of technologies, including a more accurate and reliable budget and time resources estimation to support the technology development plan. This methodology is exploited in the framework of the H2020 STRATOFLY Project to assess the potential of hypersonic civil vehicles to reach Technology Readiness Level 6 by 2035 with respect to key technological, societal and economical aspects. The paper discloses a unique assessment of the readiness level of the European air-breathing propulsive technologies. The final results confirm the crucial role of air-breathing propulsive technologies in the development of future hypersonic transportation system and highlight the urgent need to invest in in-flight demonstration missions with increasing functionalities, to target 2050 as entry in to service of the first Mach 8 civil transport. • Innovative Technology Roadmap Methodology for Hypersonic Transportation Systems. • Accurate time and budget resources estimation for each TRL transit. • Guidelines for the definition of activities, demonstrative missions or in-flight missions. • Technology Assessment of air-breathing propulsive technologies in Europe. • High-speed air-breathing technologies: TRL6 by 2035 and TRL9 by 2050 are confirmed. [ABSTRACT FROM AUTHOR]

This paper describes the methodology developed by Politecnico di Torino in support to the elaboration of hypersonic and re-entry space transportation systems roadmaps, currently on going at ESA. TRIS (Technology RoadmappIng Strategy) is here presented as a collection of algorithms leading the stakeholders from the selection of a set of elements (e.g. the technologies) up to the generation of their incremental paths towards a final target (e.g. Technology Readiness Level (TRL) 8). In particular this paper focuses on the generation and update of technology roadmaps for hypersonic and re-entry systems. In particular, the Intermediate eXperimental Vehicle (IXV) experiment is presented as validation case study, allowing the comparison of the TRL increase path suggested by the proposed methodology and the decisions that were taken at the time of the IXV mission planning. • Technology Roadmap can be carried out through a rational process. • TRIS methodology can support roadmapping strategy in multiple domains. • TRIS is supporting ESA for the updates of ESA Technology Roadmaps. • TRIS methodology has been validated through the IXV mission case study. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to suggest feasible solutions to overcome the problem of unmanned aerial vehicles integration within the existing airspace. Design/methodology/approach: It envisages innovative time-based separation procedures that will enhance the integration in the future air traffic management (ATM) system of next generation of large remotely piloted aircraft system (RPAS). 4D navigation and dynamic mobile area concepts, both proposed in the framework of Single European Sky ATM Research program, are brought together to hypothesize innovative time-based separation procedures aiming at promoting integration of RPAS in the future ATM system. Findings: Benefits of proposed procedures, mainly evaluated in terms of volume reduction of segregated airspace, are quantitatively analyzed on the basis of realistic operational scenarios focusing on monitoring activities in both nominal and emergency conditions. Eventually, the major limits of time-based separation for RPAS are investigated. Practical implications: The implementation of the envisaged procedures will be a key enabler in RPAS integration in future ATM integration. Originality/value: In the current ATM scenario, separation of RPAS from air traffic is ensured by segregating a large amount of airspace areas with fixed dimensions, dramatically limiting the activities of these vehicles. [ABSTRACT FROM AUTHOR]

Abstract Exploration technology roadmaps have been developed by ESA in the past few years and the edition of 2015 has just been released. In the context of Moon exploration initiatives and using HERACLES mission as case study, the authors will apply methodologies studied to simulate technology roadmapping activities and technologies prioritization processes. In particular, the roadmaps for the procurement of technologies required for the HERACLES mission are here presented through its main building blocks. Highlights • A tool for strategic, programmatic and technical decisions is studied. • Logical processes are used to propose strategic choices. • System Engineering and Decision Analysis are used to support the proposed methodology. • A realistic case study is proposed: a lunar reference missions in the time frame 2020 to 2030. • The main results of the proposed methodology application are there shown. [ABSTRACT FROM AUTHOR]

With an expected global revenue exceeding 1 trillion USD by 2040, the space industry is one of the world's fastest-growing sectors. Given the booming investment in the space industry and the anticipated space tourism era, it is crucial to assess the impact of already operative launch assets as well as to adopt design-to-sustainability strategies for the under-development and future launchers. This paper discloses an integrated methodology to estimate nitrogen oxides emissions of a hydrogen-fuelled air-breathing concept. The proposed strategy combines multi-fidelity propulsive system modelling with 0D chemical-kinetic air/hydrogen combustion numerical simulations to define a high-fidelity emissive database representative of various on-ground and in-flight operative conditions. The propulsive and emissive databases are then used to suggest an analytical formulation able to predict nitrogen oxides emission indices in any in-flight conditions, perfectly fitting the conceptual design needs. Throughout the paper, the Skylon spaceplane and its Synergetic Air Breathing Rocket Engine are used as case study. The methodology disclosed allows proving the high competitiveness of this air-breathing space launchers with respect to famous past and current competitors, as the Space Shuttle and the Falcon 9. [Display omitted] • Integrated design methodologies can support NOx estimations in conceptual design. • 0D chemical-kinetic simulations with Z24 scheme provides reliable E I N O x estimation. • Air-breathing launchers prove to be environmentally friendlier than conventional ones. • Upgraded P 3 T 3 method can support E I N O x estimation for hydrogen-fuelled launchers. [ABSTRACT FROM AUTHOR]

Purpose This paper aims to propose a methodology for a safety and reliability assessment for the conceptual and preliminary design of very complex and disrupting innovative systems like trans-atmospheric vehicles. The proposed methodology differs from existing ones because it does not rely on statistical data at aircraft-level but exploits the statistical population at components-level only. For the sake of clarity, the paper provides some preliminary results of the application of the methodology at system level. The example deals with the safety and reliability assessment of a very complex propulsion system aimed at guaranteeing vertical take-off and landing capabilities of a suborbital vehicle.Design/methodology/approach The proposed methodology is strongly based on a systems engineering approach. It exploits safety and reliability assessment analyses which have already been developed in both aeronautical and space engineering domains, but it combines them in an innovative way to overcome the lack of statistics at aircraft level. The methodology consists of two different steps: a qualitative top-down process, allowing a functional and physical decomposition of the transportation system and a following quantitative bottom-up approach, which provides the estimation of system-level reliability and safety characteristics starting from the statistical estimation of the components’ characteristics.Findings The paper presents a new methodology for the preliminary reliability and safety assessment of innovative transportation systems, such as hypersonic transportation systems. The envisaged methodology will overcome the poorness of statistical data that is usually affecting the conceptual design of breakthrough systems.Research limitations/implications The paper shows the application of the articulated methodology to a limited case study. A complete example of application of the methodology to estimate safety and reliability characteristics at vehicle level will be provided in feature works.Practical implications The methodology has been proposed to be exploited in international research activities in the field of hypersonic transportation systems. Furthermore, a massive application of this approach would allow to create a database for the generation and the update of semi-empirical models focused on high-level estimations of reliability, availability, maintainability and safety (RAMS) characteristics. Moreover, the proposed safety assessment has been conceived to be fully integrated within a typical conceptual design process.Originality/value The existing literature about safety and reliability assessment at the early design stages proposes pure statistical approaches which are usually not applicable to highly innovative products, where the statistical population is not existing, for example, in the case of trans-atmospheric vehicles. This paper describes how to overcome this problem, through the exploitation of statistical data at components-level only through the combination of these data to estimate RAMS characteristics at aircraft-level thanks to functional analysis, concept of operations and typical safety assessment tools, like functional hazard analysis, failure mode and effect analysis, reliability block diagram and fault tree analysis. [ABSTRACT FROM AUTHOR]

Exploration technology roadmaps have been developed by ESA in the past few years and the latest edition has been released in 2015. Scope of these technology roadmaps, elaborated in consultation with the different ESA stakeholders (e.g. European Industries and Research Entities), is to provide a powerful tool for strategic, programmatic and technical decisions in support of the European role within an International Space Exploration context. In the context of preparation for possible future European Moon exploration initiatives, the technology roadmaps have been used to highlight the role of technology within Missions, Building Blocks and Operational Capabilities of relevance. In particular, as part of reference missions to the Moon that would fit in the time frame 2020 to 2030, ESA has addressed the definition of lunar surface exploration missions in line with its space exploration strategy, with the common mission goals of returning samples from the Moon and Mars and expanding human presence to these destinations in a step-wise approach. The roadmaps for the procurement of technologies required for the first mission elements of the above strategy have been elaborated through their main building blocks, i.e. Visual navigation, Hazard detection and avoidance; Sample acquisition, processing and containment system; Surface mobility elements; Tele-robotic and autonomous control systems; and Storable propulsion modules and equipment. Technology prioritization methodologies have been developed in support of the ESA Exploration Technology Roadmaps, in order to provide logical and quantitative instruments to verify choices of prioritization that can be carried out based on important, but non-quantitative factors. These methodologies, which are thoroughly described in the first part of the paper, proceed through subsequent steps. First, technology prioritization's criteria are selected; then decision trees are developed to highlight all feasible paths of combination of technology prioritization's criteria and to assess the final achievement of each path, i.e. the cost-effectiveness. The risk associated to each path is also evaluated. In the second part of the paper, these prioritization methodologies have been applied to some of the building blocks of relevance for the mission concepts under evaluation at ESA (such as Tele-robotic and autonomous control systems; Storable propulsion modules and equipment) and the results are presented to highlight the approach for an effective TRL increase. Eventually main conclusions are drawn. [ABSTRACT FROM AUTHOR]

The paper deals with the conceptual design of a space tug to be used in support to Earth satellites transfer manoeuvres. Usually Earth satellites are released in a non-definitive low orbit, depending on the adopted launcher, and they need to be equipped with an adequate propulsion system able to perform the transfer to their final operational location. In order to reduce the mass at launch of the satellite system, an element pre-deployed on orbit, i.e. the space tug, can be exploited to perform the transfer manoeuvres; this allows simplifying the propulsion requirements for the satellite, with a consequent decrease of mass and volume, in favour of larger payloads. The space tug here presented is conceived to be used for the transfer of a few satellites from low to high orbits, and vice versa, if needed. To support these manoeuvres, dedicated refuelling operations are envisaged. The paper starts from on overview of the mission scenario, the concept of operations and the related architecture elements. Then it focuses on the detailed definition of the space tug, from the requirements’ assessment up to the budgets’ development, through an iterative and recursive design process. The overall mission scenario has been derived from a set of trade-off analyses that have been performed to choose the mission architecture and operations that better satisfy stakeholder expectations: the most important features of these analyses and their results are described within the paper. Eventually, in the last part of the work main conclusions are drawn on the selected mission scenario and space tug and further utilizations of this innovative system in the frame of future space exploration are discussed. Specifically, an enhanced version of the space tug that has been described in the paper could be used to support on orbit assembly of large spacecraft for distant and long exploration missions. The Space Tug development is an activity carried on in the frame of the SAPERE project (Space Advanced Project Excellence in Research and Enterprise), supported by Italian Ministry of Research and University (MIUR), and specifically in its STRONG sub-project (Systems Technology and Research National Global Operations) and related to the theme of space exploration and access to space. [ABSTRACT FROM AUTHOR]

Top priorities in future international space exploration missions regard the achievement of the necessary maturation of enabling technologies, thereby allowing Europe to play a role commensurate with its industrial, operational and scientific capabilities. As part of the actions derived from this commitment, ESA Technology Roadmaps for Exploration represent a powerful tool to prioritise R&D activities in technologies for space exploration and support the preparation of a consistent procurement plan for space exploration technologies in Europe. The roadmaps illustrate not only the technology procurement (to TRL-8) paths for specific missions envisaged in the present timeframe, but also the achievement for Europe of technological milestones enabling operational capabilities and building blocks, essential for current and future Exploration missions. Coordination of requirements and funding sources among all European stakeholders (ESA, EU, National, and Industry) is one of the objectives of these roadmaps, that show also possible application of the technologies beyond space exploration, both at ESA and outside. The present paper describes the activity that supports the work on-going at ESA on the elaboration and update of these roadmaps and related tools, in order to criticise the followed approach and to suggest methodologies of assessment of the Roadmaps, and to derive strategic decision for the advancement of Space Exploration in Europe. After a review of Technology Areas, Missions/Programmes and related building blocks (architectures) and operational capabilities, technology applicability analyses are presented. The aim is to identify if a specific technology is required, applicable or potentially a demonstrator in the building blocks of the proposed mission concepts. In this way, for each technology it is possible to outline one or more specific plans to increase TRL up to the required level. In practice, this translates into two possible solutions: on the one hand, approved mission concepts will be complemented with the required technologies if the latter can be considered as applicable or demo; on the other, if they are neither applicable nor demo, new missions, i.e. technology demonstrators based on multidisciplinary grouping of key technologies, shall be evaluated, so as to proceed through incremental steps. Finally, techniques to determine priorities in technology procurement are identified, and methodologies to rank the required technologies are proposed. In addition, a tool that estimates the percentage of technologies required for the final destination that are implementable in each intermediate destination of the incremental approach is presented. [ABSTRACT FROM AUTHOR]

The paper deals with the description of a methodology to properly perform space mission design, with particular attention to derivation of requirements. Several tools are usually adopted to support the design of complex missions and systems, but no very rigorous processes are available for the derivation of requirements. The methodology proposed in this paper aims at providing a general approach to exploit the main system engineering analyses and tools for a thorough assessment of the requirements. Specifically, it addresses how each category of requirements can be derived by appropriate analyses and what is generally the sequence of derived requirements categories. The very first design step is mission statement and objectives definition. A parallel activity is the stakeholders׳ needs׳ analysis, mainly based on identifying all mission׳s actors and their expectations, thus deriving additional objectives. Once the broad objectives of the missions have been established, the following step of the design methodology is the Functional Analysis, which allows identifying the major functions to be performed for the mission׳s accomplishment, as well as the needed physical components. Another important analysis is related to the Concept of Operations, which has the scope of describing how the system is operated during its life-cycle phases to meet stakeholders׳ expectations. The overall process relies on the use of specific software tools, which provide useful means for the analyses integration giving also the chance to easily track and verify the results. The paper reports a detailed description of the methodology, as well as an example case study in order to provide a clearer understanding of the entire process. The analyzed case refers to in-orbit validation of inflatable technology, which is one of the most significant technologies to be developed for future human space missions to deep space targets. Future human exploration programs point towards new and more challenging objectives, which require the development of new advanced systems and technologies, and their demonstration in space environment. Indeed a system is considered flight-qualified, once it has completed a demonstration mission in space environment. Accordingly, there is a great interest in the definition and analysis of dedicated missions for the in-orbit demonstration of advanced technologies. The developed design methodology and the results obtained by applying the methodology have been obtained in the framework of STEPS-2 (Sistemi e Tecnologie per l’EsPlorazione Spaziale-Phase 2). STEPS-2 is a research project co-founded by EU on the “Misura Piattaforme Innovative”-Phase 2 of POR FESR 2007/2013. [ABSTRACT FROM AUTHOR]

The paper deals with the mission analysis and conceptual design of an interplanetary 6U CubeSats system to be implemented in the L 1 Earth–Sun Lagrangian Point mission for solar observation and in-situ space weather measurements. Interplanetary CubeSats could be an interesting alternative to big missions, to fulfill both scientific and technological tasks in deep space, as proved by the growing interest in this kind of application in the scientific community and most of all at NASA. Such systems allow less costly missions, due to their reduced sizes and volumes, and consequently less demanding launches requirements. The CubeSats mission presented in this paper is aimed at supporting measurements of space weather. The mission envisages the deployment of a 6U CubeSats system in the L 1 Earth–Sun Lagrangian Point, where solar observations for in situ measurements of space weather to provide additional warning time to Earth can be carried out. The proposed mission is also intended as a technology validation mission, giving the chance to test advanced technologies, such as telecommunications and solar sails, envisaged as propulsion system. Furthermore, traveling outside the Van Allen belts, the 6U CubeSats system gives the opportunity to further investigate the space radiation environment: radiation dosimeters and advanced materials are envisaged to be implemented, in order to test their response to the harsh space environment, even in view of future implementation on other spacecrafts (e.g. manned spacecrafts). The main issue related to CubeSats is how to fit big science within a small package – namely power, mass, volume, and data limitations. One of the objectives of the work is therefore to identify and size the required subsystems and equipment, needed to accomplish specific mission objectives, and to investigate the most suitable configuration, in order to be compatible with the typical CubeSats (multi units) standards. The work has been developed as collaboration between Politecnico di Torino, Sapienza University of Rome, “Osservatorio Astrofisico di Torino – INAF” (Astrophysical Observatory of Torino) and Deutsches Zentrum für Luft- und Raumfahrt (DLR) in Bremen. [ABSTRACT FROM AUTHOR]

Abstract: In recent years an increasing interest in the Moon surface operations has been experienced. In the future robotic and manned missions of Moon surface exploration will be fundamental in order to lay the groundwork for more ambitious space exploration programs. Surface mobility systems will be the key elements to ensure an efficient and safe Moon exploration. Future lunar rovers are likely to be heavier and able to travel longer distances than the previously developed Moon rover systems. The Lunar Roving Vehicle (LRV) is the only manned rover, which has so far been launched and used on the Moon surface. Its mobility system included flexible wheels that cannot be scaled to the heavier and longer range vehicles. Thus the previously developed wheels are likely not to be suitable for the new larger vehicles. Taking all these considerations into account, on the basis of the system requirements and assumptions, several wheel concepts have been discussed and evaluated through a trade-off analysis. Semi-empirical equations have been utilized to predict the wheel geometrical characteristics, as well as to estimate the motion resistances and the ability of the system to generate thrust. A numerical model has also been implemented, in order to define more into the details the whole wheel design, in terms of wheel geometry and physical properties. As a result of the trade-off analysis, the ellipse wheel concept has shown the best behavior in terms of stiffness, mass budget and dynamic performance. The results presented in the paper have been obtained in cooperation with Thales Alenia Space-Italy and Sicme motori, in the framework of a regional program called STEPS 1 [1] STEPS–Sistemi e Tecnologie per l''EsPlorazione Spaziale is a research project co-financed by Piedmont Region and firms and universities of the Piedmont Aerospace District in the ambit of the P.O.R-F.E.S.R. 2007–2013 program. . [Copyright &y& Elsevier]

Purpose |!|#8211; The purpose of this paper is to describe the tool and procedure developed in order to design the control laws of several UAV (Unmanned Aerial Vehicle) sub-systems. The authors designed and developed the logics governing: landing gear, nose wheel steering, wheel braking, and fuel system. Design/methodology/approach |!|#8211; This procedure is based on a general purpose, object-oriented, simulation tool. The development method used is based on three-steps. The main structure of the control laws is defined through flow charts; then the logics are ported to ANSI-C programming language; finally the code is implemented inside the status model. The status model is a Matlab-Simulink model, which uses an embedded Matlab-function to model the FCC (Flight Control Computer). The core block is linked with the components, but cannot access their internal model. Interfaces between FCCs and system components in the model reflect real system ones. Findings |!|#8211; The user verifies systems|!|#39; reactions in real time, through the status model. Using block-oriented approach, development of the control laws and integration of several systems is faster. Practical implications |!|#8211; The tool aims to test and validate the control laws dynamically, helping specialists to find out odd logics or undesired responses, during the pre-design. Originality/value |!|#8211; The development team can test and verify the control laws in various failure scenarios. This tool allows more reliable and effective logics to be produced, which can be directly used on the system. [ABSTRACT FROM AUTHOR]

Family functioning and child participation are critical factors in recovery from traumatic brain injury (TBI) and academic and social outcomes. Using mixed methods, we investigated these factors in children who experienced early childhood TBIs and then entered formal schooling. Caregivers completed interviews and scales of family functioning and child participation. Their scores did not reflect problematic family functioning, but showed participation across settings was below average. Themes from interviews included: (1) early childhood TBIs can affect family functioning even years after the injury; (2) learning, academic, and social-emotional issues impact participation and family functioning following early childhood TBI; and (3) appropriate supports and accessible environments are critical for both family functioning and child participation across settings. Mixed methods analyses indicated convergence, divergence, and expansion between qualitative and quantitative results. Results enhance our understanding of challenges encountered after early childhood TBI and provide directions for future interventions. [ABSTRACT FROM AUTHOR]

This paper aims to provide technical insights on the aerodynamic characterization activities performed in the field of the H2020 STRATOFLY project, for the Mach 8 waverider reference configuration. Considering the complexity of the configuration to be analyzed at conceptual/preliminary design stage, a build-up approach has been adopted. The complexity of the aerodynamic model increases incrementally, from the clean external configuration up to the complete configuration, including propulsion systems elements and flight control surfaces. At each step, the aerodynamic analysis is complemented with detailed mission analysis, in which the different versions of the aerodynamic databases are used as input for the trajectory simulation. eventually, once the contribution to the aerodynamic characterization of flight control surfaces is evaluated, stability and trim analysis is carried out. The comparison of the results obtained through the different mission analysis campaigns clearly shows that the accuracy of aerodynamic characterization may determine the feasibility or unfeasibility of a mission concept. [ABSTRACT FROM AUTHOR]

Embedded propulsion systems will allow future hypersonic aircraft to reach amazing levels of performance. However, their peculiar small-radius air-intake leading edges pose serious challenges from the aerothermodynamic, design, integration, and manufacturing standpoints. This paper discloses the methodology developed in the framework of the H2020 STRATOFLY project and specifically tailored to support the conceptual and preliminary design phases of future high-speed transportation systems. The methodology implements an incremental approach which includes multi-fidelity design, modelling and simulation techniques. The specific application to the MR3, a Mach 8 waverider configuration with an embedded dorsal mounted propulsive subsystem, is reported. Different alternative solutions have been thoroughly analysed, including five liquid metals as fluids (Mercury, Caesium, Potassium, Sodium and Lithium) and relative wick and case materials (Steel, Titanium, Nickel, Inconel® and Tungsten) and three leading-edges materials (CMC, Tungsten with low emissivity painting and Tungsten with high emissivity painting). The analysis of the heat transfer limits (the capillary, entrainment, viscosity, chocking and boiling limits) carried out for all five fluids and relative compatible materials, together with a more accurate FEM analysis, suggest the adoption of a Nickel–Potassium liquid metal heat pipe completely integrated in a platelet air-intake leading edge made of CMC material. Ultimately, the effectiveness of the adopted solution throughout all mission phases has been verified with a detailed numerical model, built upon an electrical analogy. • Liquid Metals Heat-Pipe solution for hypersonic air-intake leading edge. • Integrated design methodology with multi-fidelity modelling & simulation techniques. • Application to the STRATOFLY MR3 Mach 8 waverider concept. • Nickel–Potassium liquid metal heat pipe in a CMC platelet air-intake leading edge. • Verification of the effectiveness of the solution throughout all mission phases. [ABSTRACT FROM AUTHOR]

According to the Global Exploration Roadmap, a Getaway in the lunar vicinity will enable the human exploration of the Moon, paving the way toward Mars and further in the deep space. A reusable transportation system, the Lunar Space Tug (LST), can be a key support transportation system to achieve a continuous and sustainable connection between the Earth and the orbital lunar outpost. Exploiting an electrical propulsion technology consisting in Hall Thrusters (HTs), this reusable space cargo system can maximize the delivered payload, with a lower propellant consumption with respect to a chemical-based platform. This significant improvement comes with two main throwbacks: a long transfer time between Earth and Moon and a complex multidisciplinary design of the overall LST. The first issue can be overcome with good mission planning in order to reduce the layover times and maximize the use of the LST. However, the peculiarities of the adopted propulsion technology shape the overall mass and power distribution of the space tug, as well as its transfer trajectory. The design complexity introduced by this subsystem can be effectively investigated if the mission analysis, trajectory generation and subsystem sizing are merged together in one software. In fact, the low-thrust transfer trajectories are highly affected by orbital perturbation and eclipse periods. At the same time, the high demand in power of the propulsion system puts constraints on the mass breakdown and power allocations of the LST, therefore on the reachable thrust level. The trajectory and subsystems sizing limitations call for a particular accurate mission analysis in order to succeed. Only combining all those elements, it is possible to define feasible design boundaries without performing countless simulations trying to optimize each element as a stand-alone part. Politecnico di Torino, in collaboration with the European Space Research and Technology Centre (ESTEC), developed a MatLab-based preliminary design tool for electric propulsion space tug missions, called MultidisciplinAry desiGN Electric Tug tOol (MAGNETO). Starting from the mission analysis of the lunar space tug, the tool building blocks and capabilities are presented. Moreover, the build-in trajectory module will be analysed in-depth. The potentiality of the trajectory generation tool in MAGNETO enables a refined design of the initial design envelope of the LST. For this reason, the improved results will be confronted with the previous LST design tool developed by Politecnico di Torino. • Conceptual design analysis tool of an electrically propelled space tug. • Mass and power breakdown allocations for a space tug main subsystems. • Generation of a preliminary sub-optimal low-thrust trajectory. • Analysis of a payload cargo mission toward the lunar gateway. [ABSTRACT FROM AUTHOR]

Abstract Italy, as well as many other countries, has increasing interest in Commercial Space Transportation and in particular, in suborbital flights. A suborbital space transportation system is an opportunity to involve the Italian industry in the development of new technologies, exploit opportunities of microgravity experimentation and pilots/astronauts training, as well as catalyse the national industry. The central position of Italy in the Mediterranean basin, the generically favourable climate condition, the touristic vocation resulting in hospitality at the highest level, pretty much allow year round suborbital operations and unique customer experience. Consequently, Italy appears to be a suitable location to host a Spaceport, even though the density of population has to be factored in as a key aspect, together with a proper environmental assessment. This paper outlines the current Italian approach that, instead of focusing on the development of new Spaceport from scratch, evaluates the capabilities of existing airports and their possible upgrades to achieve the Spaceport license, when a proper regulatory frame is established. Advances in the technical activities that are being conducted to assess various Italian sites of interest are described, including trade off methodologies and ranking criteria. Different aspects are considered, from the availability of civil and military airports, to the identification of the best location between coastline or inland sites but, first of all, in compliance to the safety requirements. Some specific Spaceport infrastructure and operational aspects are described, along with their integration with the already existing ones. These include hangars, propellant storage facilities, ground support equipment, high and low airspace surrounding the airport area, ascent and descent corridors, as well as tracking telemetry station to support specific mission profiles in integrated fashion with the existing airport infrastructure and air traffic. The paper will also describe the approach to the definition of a harmonized cooperative regulatory framework, according to the Aviation Authority, that represents the basis to assess suborbital operations and allows the relevant missions execution. In this activity, basing upon an established Memorandum of Cooperation between FAA, ENAC and the Italian Space Agency, the existing FAA/AST regulatory work frame is considered as reference benchmark and further tailored to the Italian case. Some considerations will also be developed relevant to initial challenges to be faced, by interested stakeholders, in starting commercial spaceflight initiatives as a new ground and emerging business opportunity. Highlights • Spaceport and Ground Segment assessment for future suborbital transportation system. • Market opportunities and benefits for the Italian economy. • Spaceport requirements identification for the Italian case. • Spaceport operations business strategy considerations for the Italian case. [ABSTRACT FROM AUTHOR]

The present work provides a method for maintenance cost estimation for a civil aircraft. The model evaluates maintenance costs at a subsystem level in order to quantify the effective impact of each aircraft part on the total maintenance cost. An analysis at the subsystem level can offer a more precise cost estimation because the most influential parameters (that is, the cost drivers) should be different for each aircraft part. Emphasis is given on the updating of a cost-estimating model proposed in 1966 that provided equations for the maintenance cost assessment at a subsystem level using the Air Transport Association nomenclature. The reference method is enhanced with additional cost items, and the choice of cost drivers is accurately considered. The application of the developed model shows good accordance with the reference values provided by the International Air Transport Association, and results are compared with the common state-of-the-art methods. [ABSTRACT FROM AUTHOR]

The Moon is now being considered as the starting point for human exploration of the Solar System beyond low-Earth orbit. Many national space agencies are actively advocating to build up a lunar surface habitat capability starting from 2030 or earlier: according to ESA Technology Roadmaps for Exploration this should be the result of a broad international cooperation. Taking into account an incremental approach to reduce risks and costs of space missions, a lunar outpost can be considered as a test bed towards Mars, allowing to validate enabling technologies, such as water processing, waste management, power generation and storage, automation, robotics and human factors. Our natural satellite is rich in resources that could be used to pursue such a goal through a necessary assessment of ISRU techniques. The aim of this research is the analysis of a Moon outpost dedicated to the validation of enabling technologies for human space exploration. The main building blocks of the outpost are identified and feasible evolutionary scenarios are depicted, to highlight the incremental steps to build up the outpost. Main aspects that are dealt with include outpost location and architecture, as well as ISRU facilities, which in a far term future can help reduce the mass at launch, by producing hydrogen and oxygen for consumables, ECLSS, and propellant for Earth-Moon sorties and Mars journeys. A test outpost is implemented in a Virtual Reality (VR) environment as a first proof-of-concepts, where the elements are computer-based mock-ups. The VR facility has a first-person interactive perspective, allowing for specific in-depth analyses of ergonomics and operations. The feedbacks of these analyses are crucial to highlight requirements that might otherwise be overlooked, while their general outputs are fundamental to write down procedures. Moreover, the mimic of astronauts' EVAs is useful for pre-flight training, but can also represent an additional tool for failures troubleshooting during the flight controllers' nominal operations. Additionally, illumination maps have been obtained to study the light conditions, which are essential parameters to assess the base elements location. This unique simulation environment may offer the largest suite of benefits during the design and development phase, as it allows to design future systems to optimize operations, thus maximizing the mission's scientific return, and to enhance the astronauts training, by saving time and cost. The paper describes how a virtual environment could help to design a Moon outpost for an incremental architecture strategy towards Mars missions. [ABSTRACT FROM AUTHOR]

Test and qualification (T&Q) phases take a significant portion of the time to market for critical products in the space industry, especially when introducing new technologies. Since T&Q are treated as standard procedures, they tend to be independent of the architectural design phases and kept away from design decisions. However, when introducing new technologies, qualification procedures may differ from those established in regular design scenarios, and the estimation of qualification costs and duration is problematic. There is a lack of design for qualification methods capable of modelling these activities in early phases and use those models to support the architecture design of products with affordable test and qualification phases. In this article, a computer-assisted, model-based design method to model T&Q activities concerning early product architecture designs is proposed. Product architecture alternatives, test schedules and cost are connected through the quantification of T&Q drivers and driver rates. The design method is demonstrated using a case study about electric propulsion for satellites. The method is applicable for design situations where the choice of technology has a strong dependence on the qualification procedure. [ABSTRACT FROM AUTHOR]

Abstract Since the early history of Space Exploration, Mars conquest has been the most important target. After Apollo mission's Moon landing, several concepts and projects, concerning a mission on the Red Planet, were developed. One of the most important contributes was given by Buzz Aldrin, who theorized the use of particular kind of orbits, called cycler orbits, as baseline for an enduring Mars colonization. A cycler orbit is a kind of orbit which repeats every integer multiple of synodic period and which encounters two bodies with a precise schedule. In the case, the bodies considered are Earth and Mars. It is possible to inject a space station in the cycler orbit which allows a continuous transfer of a crew from Low Earth Orbit to Mars Low Orbit and vice-versa. Small taxi vehicles are used to rendezvous the cycler station from the two bodies, significantly reducing the amount of propellant. In this paper a mission architecture based on this new concept was analysed, in order to develop an alternative mission profile compared to the actual architectures proposed for human missions. The work starts with an analysis of several classes of cycler. Through a trade-off analysis an unique class of cycler was identified as baseline for a further mission analysis. The mission analysis consists of an evaluation of orbital perturbation, the computation of ΔV required for injection and rendezvous manoeuvres and an identification of close approach windows of the cycler with the two planets, allowing an evaluation of mission duration. Eventually, the presented mission concept was compared with more classical concepts, focusing on a key figure to enable Mars colonization, sustainability. Finally the proposed architecture should be seen as a preliminary assessment of an alternative solution to the currently proposed enabling architectures for the Martian exploration. Highlights • Earth-Mars transfer scenario reducing launch cost by 50% wrt to NASA DRA 5.0. • Reutilization of transfer habitats for 14 return travels to Mars. • Distributed deployment of Mars exploration systems for a sustainable development. • Nuclear free solution. • Transfer time compatible with other reference scenario. [ABSTRACT FROM AUTHOR]

Abstract The Lunar Space Tug is a sustainable transportation system able to rendezvous with a target body in Low Earth Orbits environment, assess its current position, attitude and operational status, capture the target and move it to the Cislunar space where the Lunar Orbital Platform-Gateway will be settled. Thanks to the adoption of an electric Propulsion Subsystem based of Hall Effect Thruster clusters, the Lunar Space Tug can save fuel to the detriment of much longer transfer time to deliver the unmanned cargo to the cislunar Gateway. Since the Lunar Space Tug has been conceived to be reusable, one of the main issue is related to the on-orbit refueling to sustain the Lunar Space Tug during its operational lifetime. Each mission scenario shall take into account the effects related to refueling operations according to mission requirements and constraints. Considering the whole mission scenario in which the Lunar Space Tug will operate, this paper focuses on mission analysis and conceptual system design, including typical systems budgets, like transfer duration, Δv, mass and power. Moreover, according to the transfer duration and the needs of the Lunar Orbital Platform-Gateway, a preliminary trade-off analysis has been accomplished to investigate the possibility of using a fleet of Lunar Space Tug instead of a single tug, taking onto account safety, reliability, costs and operations issues. The identified optimal configuration is then compared with the current reference option, i.e. the NASA Space Launch System adopted as cislunar delivery vehicle. Highlights • Electric Space Tug for unmanned transfer between Earth and Cislunar Infrastructures. • New sustainable way to transport cargo module relying on longer transfer time and uncommon mission scenario. • Mission and system design strongly affected by adoption of electric propulsion. • LST fleet concept validated wrt mission and system constraints. • Analysis of on-orbit refueling operations impact on the mission. [ABSTRACT FROM AUTHOR]

Abstract: Traveling beyond LEO is the next step in the conquest of the solar system and so far, a human expedition to Mars is considered the most interesting goal of the future Human Space Exploration (HSE). Due to the technological and operational challenges associated to a human mission to the Red Planet, it is necessary to define an opportune path of exploration, relying on many missions to intermediate and “easier” destinations, which would allow a gradual achievement of the capabilities required for the human Mars mission. According to the actual interest in this topic, a study was carried out with the aim of defining a HSE reference scenario and analyze the relative technological issues. The reference scenario was built considering as final target the human mission to Mars as defined by NASA DRA 5.0. The intermediate destinations were selected so that they will guarantee the implementation and achievement, through a step-by-step approach, of all the capabilities required to accomplish the human mission to Mars. All the scenario destinations’ missions were analyzed and characterized in terms of strategies, architectures and needed building blocks. Then specific analyses concerning the key technologies to accomplish those missions were performed, starting from the definition of a large database collecting the most innovative and not yet space qualified technologies up to the analysis of how the most important ones are implementable through the various destinations and missions elements. The obtained results are represented by a versatile tool, useful to support strategic decisions, allowing understanding and visualizing where, when and in which elements each technology can potentially be applied and tested (maybe at limited extent), before being implemented in a specific mission where it is absolutely required. This could be very helpful to well place investments in the development of specific systems to allow future space exploration missions. The paper, after an overview of the HSE reference scenario and of the process followed to build it, focuses on the description of the methodology defined to build a tool for technologies roadmaps assessment. Specific examples are provided to better explain how the tool can be exploited. [Copyright &y& Elsevier]

Abstract: SpacE Exploration and Development Systems (SEEDS) initiative originated from Politecnico di Torino and Thales Alenia Space Italy in 2005. It aimed at establishing a postgraduate international master course in space exploration and development systems to offer an opportunity to young engineers to get prepared for the future of Europe in space exploration. SEEDS project has been shared with Supaero Toulouse in France and with University of Bremen (together with the Center of Applied Space Technology and Microgravity, ZARM) in Germany. SEEDS course comprises of two different steps in sequence: an initial learning phase and a project work phase. The distinguishing feature of SEEDS is without any doubt the project work phase, which includes the preparatory work and the conceptual design activities, performed in three European sites to develop a limited number of building blocks identified during the preparatory work. The first year of activity started in November 2005. Five years of activities have passed since then and five project works have been successfully completed, dealing with various space exploration themes. The paper focuses on the description of SEEDS master course, in terms of master course structure, applied methodology and students team organization, and on the main results achieved, in terms of project work activities and development of future space workforce. The positive experience of five years of SEEDS is brought to evidence and lessons learned are discussed in view of SEEDS continuation. [Copyright &y& Elsevier]

Purpose |!|#8211; The purpose of this paper is to perform a technical and economical analysis on the conversion of a regional turboprop platform for Airborne Early Warning and Control (AEW|!|#38;C) missions by supposing installation of supplementary diesel turbo-charged engines. Design/methodology/approach |!|#8211; The problem has been approached by considering all issues related to conversion to AEW|!|#38;C platform. Class II methods have been used for weight and drag estimations. Flight performances have been evaluated by using standard equations of flight mechanics. Costs have been evaluated by using a model developed by the authors. Findings |!|#8211; As far as performances are concerned, it is possible to increase aircraft service ceiling of about 4,400|!|#8201;ft by installing auxiliary diesel engines in separate wing-nacelles. The low specific fuel consumption (SFC) of diesel engines balances the reduction of mission endurance caused by the aerodynamic drag increment (i.e. additional drag of AEW radar antenna and new nacelles). The proposed solution is shown to have the best Effectiveness-Cost performance in comparison with other AEW|!|#38;C aircraft-systems. Practical implications |!|#8211; To convert regional turboprops to AEW|!|#38;C platform by employing turbocharged diesel engines could be an interesting future perspective for aerospace companies interested in creating a new AEW|!|#38;C market segment. Originality/value |!|#8211; The proposed solution gives the possibility to reduce operating costs in the AEW|!|#38;C mission field. The issue is actual due to typical high operating costs of AEW|!|#38;C missions. [ABSTRACT FROM AUTHOR]