Advanced European Re-Entry System Based on Inflatable Heat Shields: Detailed Design (EFESTO project)

The European Union H2020 EFESTO project is coordinated by DEIMOS Space with the end goals of improving the European TRL of Inflatable Heat Shields for re-entry vehicles (from 3 to 4/5) and paving the way towards further improvements (TRL 6 with a future In-Orbit Demonstrator, IOD). This paper presents the project objectives and the initial results of the detailed design of atmospheric entry missions based on the applications of advanced thermal protection systems implementing inflatable heat shields (flexible TPS and inflatable structures), according to aerothermodynamics constraints for future in-orbit demonstration. Placing the future IOD mission in the context of ongoing and future efforts in the European context is also one of the project goals. Two key applications, Mars Robotic Exploration and Reusable Small Launchers Upper Stages, have been identified. For the Mars Application, the robotic exploration mission class resulted in a 10 m diameter Hypersonic Inflatable Aerodynamic Decelerator (HIAD) class, combined with Supersonic Retro-Propulsion (SRP, activated about Mach 2.3) to deliver about 2800 kg of payload at MOLA +2 km. For the Earth Application, the VEGA upper stage (AVUM) has been selected as baseline case study. The current mission foresees a deorbiting from SSO orbit, a controlled entry phase (BC of about 30 kg/m2) and combines the use of a HIAD (4.5m diameter class) with parachutes and parafoil for Mid-Air-Capturing (MAR) with a helicopter. Beyond feasibility of the entry mission phase and system design with an inflated IAD, integration aspects have a key impact in the specific design solutions adopted, due to the nature of an inflatable heatshield. For both considered application cases feasible architectures are developed responding to the challenge of integrating the HIAD into the system in compliance with geometric and functional requirements. While the HIAD in folded state prior to inflation must fit in the available volume, it has limitations with respect to the density imposing a minimum cross section of the stowage volume. Simultaneously requirements with respect to the centre of gravity position during re-entry with an inflated HIAD must be respected for stability and controllability reasons. Other architectural considerations such as payload integration for the application on a launcher upper stage must be considered. Finally, heat loads constraints are considered for the trajectory and TPS deign choices due to important fluid-structure interactions. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 821801

EFESTO - advancing European hypersonic inflatable heatshield technology for Earth recovery and Mars high-mass delivery missions

The European Union H2020 EFESTO project is coordinated by DEIMOS Space with the end goals of improving the European TRL of Inflatable Heat Shields for re-entry vehicles (from 3 to 4/5) and paving the way towards further improvements (TRL 6 with a future In-Orbit Demonstrator). This paper presents the project objectives and provides with a general overview of the activities ongoing and planned for the next two years, promoting its position in the frame of a European re-entry technology roadmap. EFESTO aims at (1) the definition of critical space mission scenarios (Earth and Mars applications) enabled by the use of advanced inflatable Thermal Protection Systems (TPS), (2) characterization of the operative environment and (3) validation by tests of both the flexible materials needed for the thermal protection (flexible thermal blanket will be tested in arcjet facility in both Earth and Martian environments) and the inflatable structure at 1:2 scale (exploring the morphing dynamics and materials response from packed to fully inflated configuration). These results will be injected into the consolidated design of a future In-Orbit Demonstrator (IOD) mission

Advanced European Re-Entry System Based on Inflatable Heat Shields EFESTO project overview: preliminary IOD mission and system definition

The European Union H2020 EFESTO project is coordinated by DEIMOS Space with the end goals of improving the European TRL of Inflatable Heat Shields for re-entry vehicles from 3 to 4/5 and pave the way to an In-Orbit Demonstration (IOD) that can further raise the TRL to 6. This paper provides a synthesis of the EFESTO design and experimental achievements and sums up the Inflatable Heatshield IOD mission and system design which is the final step of the EFESTO project. First, the initial IOD design resulted from a dedicated concurrent engineering analysis is introduced. The session core consisted of trading-off on the system configuration options derived from the sequential design and testing campaigns, including the Inflatable Structure (IS) and Flexible Thermal Protection Systems (F-TPS) key subsystems, but also on additional aspects such as launcher and landing site selection. The driving rationale here corresponded to the maximization of the scientific return of the experiment while also taking into account feasibility considerations related to the current European Space Sector capabilities and market opportunities. The subsequent design phase focused instead on harmonizing and the mission and system definition and extending it with a preliminary assessment of the IOD system realization and mission implementation. This final output represents a unique contribution of the EFESTO project to the European know-how in inflatable heatshield technology and promotes the relevance of the EFESTO Consortium in the frame of a European re-entry technology roadmap

EFESTO-2: European Flexible Heat Shields Advanced TPS Design and Tests for Future In-Orbit Demonstration - 2

EFESTO-2 is an EU-funded project under Horizon Europe that aims to enhance European expertise in Inflatable Heat Shields (IHS). Building on the achievements of the previous EFESTO project (H2020 funds No 821801), EFESTO-2 focuses on advancing key IHS technologies to increase their Technology Readiness Level (TRL). The project pillars include analyzing the business case for IHS applications, exploring additional aspects of IHS, improving tools and models, and establishing a development roadmap for IHS systems. This paper outlines the project objectives and plan, highlighting ongoing and future activities for the next two years, positioning it within the European re-entry technology roadmap. Funding was provided by the European Union's Horizon Europe program (grant agreement No 1010811041)

Development of new analytical models for pressure and heat flux distribution on space debris afterbodies

International audienceIn order to better predict the risk induced by orbital debris during their atmospheric re-entry, phenomena in the “shadow region” of the debris, i.e. the region that is not directly impinged upon by the freestream flow, were investigated. Four types of flow were shown to cause significant values of heat flux in the shadow region, for continuous hypersonic hyperenthalpic incoming flow conditions : attached flow, detached flow with fluid or solid reattachment, and shock-shock interactions. Models for pressure and heat flux distributions resulting from attached flows on cylinders leeward side were realized using Proper Orthogonal Decomposition interpolation

Noncatalytic and Finite Catalytic Heating Models for Atmospheric Re-entry Codes

International audienceThe total wall heat flux is one of the key quantities in the evaluation of the ground risk associated to debris atmospheric entry. The computed heat flux assuming catalytic wall or thermochemical equilibrium gas can be twice as large as the non-catalytic wall heat flux, leading to an underestimation of the ground risk. However, most of the models proposed in open literature allow computing stagnation point heat flux for thermochemical equilibrium air gas or chemical nonequilibrium air gas with catalytic walls only, or requires many local quantities that are not yet accessible for engineering atmospheric codes. For these reasons, ONERA developed and successfully validated new analytical models to compute the total heat flux received by the wall assuming any inflow gas state as well as finite-catalytic and non-catalytic wall material properties. These new models have been developed from a large in-house CFD database built-up with the ONERA Navier-Stokes code for various flow conditions (altitude from 70 to 20 km, velocity from 8 to 1 km/s) including different thermochemical air flow assumptions in the shock layer (perfect gas, thermochemical equilibrium and nonequilibrium real gas), effects of the nose radius (from 0.01 m to 1 m) and wall temperature (from 300 K to 2000 K). The present paper proposes an overview of the current research with a focus on the new models developed and their application relevant to on the aerothermodynamic study of the atmospheric entry of a launcher tank. A specific attention is given to the influence of the wall catalycity on the thermal degradation of such debris

EFESTO - advancing European hypersonic inflatable heatshield technology for Earth recovery and Mars highmass delivery missions

The European Union H2020 EFESTO project is coordinated by DEIMOS Space with the end goals of improving the European TRL of Inflatable Heat Shields for re-entry vehicles (from 3 to 4/5) and paving the way towards further improvements (TRL 6 with a future In-Orbit Demonstrator). This paper presents the project objectives and provides with a general overview of the activities ongoing and planned for the next two years, promoting its position in the frame of a European re-entry technology roadmap. EFESTO aims at (1) the definition of critical space mission scenarios (Earth and Mars applications) enabled by the use of advanced inflatable Thermal Protection Systems (TPS), (2) characterization of the operative environment and (3) validation by tests of both the flexible materials needed for the thermal protection (flexible thermal blanket will be tested in arcjet facility in both Earth and Martian environments) and the inflatable structure at 1:2 scale (exploring the morphing dynamics and materials response from packed to fully inflated configuration). These results will be injected into the consolidated design of a future In-Orbit Demonstrator (IOD) mission

European Flexible Heat Shields: Advanced TPS Design and Tests for Future in-Orbit Demonstration

The European Union H2020 EFESTO project is coordinated by DEIMOS Space with the end goals of improving the TRL of Inflatable Heat Shields for re-entry vehicles (from 3 to 4/5) and paving the way towards further improvements (TRL 6 with a future In-Orbit Demonstrator). This paper presents the project objectives and provides with a general overview of the activities ongoing and planned for the next three years, promoting its position in the frame of a European re-entry technology roadmap

Mission Analysis, GNC and ATD for Reusable Launch Vehicles within ASCenSIon: multi-orbit multi-payload injection, re-entry and safe disposal

Reusable Launch Vehicles (RLVs) are not only key for an economically and ecologically sustainable space access but also represent a paramount innovation towards the increasing demand for smaller satellites and mega- constellations. In order to ensure Europe's independent space access capabilities, ASCenSIon (Advancing Space Access Capabilities - Reusability and Multiple Satellite Injection) is born as an innovative training network with fifteen Early Stage Researchers, ten beneficiaries, and fourteen partner organisations across Europe. This paper provides an overview of the mission, ranging from the ascent to the re-entry of the reusable stages and including the multi-orbit injection and the safe disposal. A special focus is put on the activities developed within ASCenSIon regarding Mission Analysis (MA), Guidance Navigation and Control (GNC) and Aerothermodynamics (ATD). The foreseen methods, approaches and goals of the project are presented. These topics require innovation within and a high level of collaboration due to their interconnection. The pre-flight design capability drives the necessity of a MA and GNC missionisation tool coupled with ATD software to test/explore re-entry solutions. Such a reliable and efficient tool will require the development of GNC algorithms for the re-entry of the launcher. Additionally, specific challenges of trajectory optimization for RLVs are addressed, such as integrated multi-disciplinary vehicle design and trajectory analysis, fast and reliable on-board methods. The results of this study are subsequently used to develop the controlled strategy. Moreover, to perform the novel multi-orbit multi-payload injection. This activity is followed by the development of, a GNC architecture capable of optimally steering the vehicle towards a targeted landing site under precision and soft-landing constraints. In addition, ATD affects the mission profile at multiple phases and needs to be considered at each design step. Due to complexity and limited computational resources during the preliminary design phase, surrogate models with low response times are required to predict wall heat fluxes along the considered trajectories based on the pressure topology. The complete profile is wrapped up with the Post Mission Disposal strategies to be used by the launchers in order to ensure the compliance with the space debris mitigation guidelines, as well as preliminary reliability aspects of these strategies. The paper provides a preliminary analysis of the discussed topics and their interconnections within the work-frame of ASCenSIon paving the way towards the development of novel cutting-edge technologies for RLVs

Advanced European Re-Entry System Based on Inflatable Heat Shields: EFESTO-2 project overview

EFESTO-2 (European Flexible Heat Shields: Advanced TPS Design and Tests for Future In-Orbit Demonstration – 2) is a project funded by the EU program Horizon Europe. It aims to further increasing the European know-how in the field of Inflatable Heat Shields (IHS), an innovative technology used for thermal protection during re-entry. The project builds upon the great achievements of the father project EFESTO (H2020 funds No 821801) and seeks to improve further the Technology Readiness Level (TRL) of IHS. The project has four main pillars: (1) to consolidate the use-case applicability through a business case analysis for a meaningful space application; (2) to extend the investigation spectrum of the father project EFESTO to other critical aspects of the IHS field; (3) to increase the confidence-level and robustness of tools/models; (4) to consolidate the roadmap and guarantee continuity in presiding the IHS field in Europe among the scientific and industrial community. This paper presents the project’s objectives, achievements, ongoing activities, and planned activities up to completion. The aim is to provide a comprehensive overview of the project’s contributions to the European re-entry technology roadmap. This project has received funding from the European Union’s Horizon Europe research and innovation program under grant agreement No 1010811041