Main Challenges and Goals of the H2020 STRATOFLY Project

Abstract

As eluded in previous studies, with special reference to those carried out in the European framework, some innovative high-speed aircraft configurations have now the potential to assure an economically viable high-speed aircraft fleet. They make use of unexploited flight routes in the stratosphere, offering a solution to the presently congested flight paths while ensuring a minimum environmental impact in terms of emitted noise and green-house gasses, particularly during stratospheric cruise. Only a dedicated multi-disciplinary integrated design approach could realize this, by considering airframe architectures embedding the propulsion systems as well as meticulously integrating crucial subsystems. In this context, starting from an in-depth investigation of the current status of the activities, the STRATOFLY project has been funded by the European Commission, under the framework of Horizon 2020 plan, with the aim of assessing the potential of this type of high-speed transport vehicle to reach Technology Readiness Level (TRL) 6 by 2035, with respect to key technological, societal and economical aspects. Main issues are related to thermal and structural integrity, low-emissions combined propulsion cycles, subsystems design and integration, including smart energy management, environmental aspects impacting climate change, noise emissions and social acceptance, and economic viability accounting for safety and human factors. This paper aims at summarizing the main challenges and goals of the STRATOFLY project, highlighting the steps forward with respect to the past European Projects and underlying the next planned goals.

Business roadmap for the European Union in the NewSpace ecosystem: a case study for access to space

“…The main difference is focused on their design solutions, such as propellant choice, higher structural indices due to the low density hydrogen and its robust design philosophy with an emergency rescue system for the passengers, less tons of payload, more realistic flight trajectories, and dedicated passenger rescue capsule in case of emergency [20]. While STRATOFLY, a commercial civil high-speed transportation flight would try to achieve lightweight structures, optimize the performance and efficiency of the propulsion systems by means of ABEP (Air-Breath Electric Propulsion) systems, reduce the noise level due to high-speed jects, enhance the efficiency of the tank, use of Liquid hydrogen as a propellant, and improve the thermal protection system [21].…”

“…On the other hand, the STRATOFLY MR3 concept highlights the level of maturity of the enabling technologies for future hypersonic vehicles, which can operate both as high-speed civil passenger transport aircraft and as a first stage of reusable access to space vehicles [21]. To do this, it takes advantage of the legacy of European projects such as LAPCAT I and II, ATLAS I and II, HEXAFLY, and FAST 20XX exploiting various technological as well as industrial capabilities such as: (1) double or multiple bubble structure to achieve lighter structures with multifunctional roles to harmoniously integrate all vehicle subsystems, reduce noise and optimize aerodynamics, (2) exploitation of liquid hydrogen as fuel to drastically improve performance, (3) the inclusion of thermal protection systems and Energy Management Subsystem (TEMS) conceived in the LAPCAT-II project [46] based on ceramic matrix compounds (CMC) and heat pipes to cool the leading edges of the vehicle, (4) the reduction of noise produced by high-speed jets through strategies based on the integration of the nozzle-fuselage, and (5) the development of Air-Breathing Electric Propulsion (ABEP) technologies.…”

“…According to Nicole Viola, Principle Investigator of STRATOFLY H2020 project, "STRATOFLY MR3 has the ambitious goal of satisfying the need that urges Europe to shorten the time of flights for long-haul routes and at the same time to move toward a more sustainable aviation from the environmental point of view: zero CO 2 emissions are guaranteed thanks to the exploitation of liquid hydrogen and NO X emissions as well as noise shall be mitigated" [21] and lower operational costs thanks to proportionality on lost weight.…”

“…On the one hand, as it is noted that there is a growing market demand that asks for the development of a satellite launch solution that (1) reduces the launching and operational costs [20,21,57], (2) enables launcher in-orbit operations such as multi-orbit injection, and (3) provides sufficient flexibility [13,23,37,50]. The development of these industrial capabilities by the EU will meet the low-cost demand of the NewSpace companies [13].…”

“…Three typical examples of this type of space transportation are (1) SpaceX with the BFR (Big Falcon Rocket) concept with vertical take-off landing characteristics [20], (2) the German Aerospace Center with DLR's SpaceLiner concept with horizontal take-off landing characteristics [20], and (3) the European project H2020, STRATOFLY, led by the Italian University Politecnico di Torino. This last concept represents the first step towards future reusable launchers enabling high-speed civil transportation at stratospheric altitudes [21,22]. These three concepts aim to: (1) transport satellites and/or passengers, and (2) offer a drastic reduction in launch costs thanks to the reuse and mass production of hardware [20,22].…”