Eugénie Avril
email: eugenie.avril@univ-jfc.fr

Jordan Navarro
email: jordan.navarro@univ-lyon2.fr

Julien Cegarra
email: julien.cegarra@univ-jfc.fr

The effects of information and action automation on the complacency phenomenon

Keywords: Human-centered computing-Human computer interaction (HCI)-HCI Complacency, human-machine interaction, automation failures, reliability, interface, eye movements

Automated systems are becoming increasingly prevalent in our societies. Several authors have identified the existence of the complacency phenomenon in supervision tasks, which imply automation execution or industrial computer support. The purpose of this study was to investigate failures of cooperation between human operator and automation. In this paper, we focused on the complacency as a low degree of suspicion towards the proposals of automation, leading to a monitoring deterioration. The main objective was to compare two types of automation, action automation vs information automation, in complacency. We recruited 96 participants to complete three tasks from the Multi-Attribute Task Battery. We found an effect of two types of automation on performance. Detection rate and reaction time were better when failures were reported by information automation than when it was not reported. Eye movements data showed that the automated task was less monitored when the reliability of information was high. We did not find an effect of reliability on NASA TLX score. Finally, we found that information automation can lead to complacency phenomenon.

Introduction

For some years now, we have witnessed an increase in automation in our daily lives. These systems are present through action automation rather than human operator (e.g., aircraft piloting) and through information automation that pre-processes and displays information (e.g., an interface). In a dynamic situation, automation usually executes an action and due to time pressure, some tasks are delegated to the automation to facilitate human decision-making. However, in a static situation -such as the planning delivery in the transportation domain -time pressure is of secondary importance. The automation effort is more focused on the simplification of the data to be considered by the human operator (Cegarra and Van Wazel, 2012). A theoretical model that clearly distinguishes the functions of automation related to action and information was developed [START_REF] Parasuraman | A model for types and levels of human interaction with automation[END_REF]. Although information automations are present everywhere through interfaces (visual indicator, smartphone, etc.), the consequence of their use on the human operator are not fully understood. These information automations improve the external representation and pre-process data. However, their use can cause difficulties and is not without consequences. The failures in human-machine cooperation in terms of action automation have already been shown in a dynamic situation (Parasuraman and Riley, 1997). Therefore, it is necessary to investigate these failures in information automation. Designers need to understand these failures to consider the consequences in the design of the interface. The phenomenon of complacency is one of the possible consequences that has emerged in multitasking situations [START_REF] Parasuraman | Complacency and bias in human use of automation: An attentional integration[END_REF]. It is defined as a low degree of suspicion towards the proposals of automation, leading to suboptimal monitoring. This phenomenon appears in a situation in which human monitors automation (1), the frequency of this monitoring is lower than a standard or optimal value, and (3) performance is affected because of the suboptimal monitoring (3). The complacency phenomenon was investigated mainly in laboratory experiments by manipulating the reliability of automation [START_REF] Parasuraman | Performance consequences of automation-induced complacency[END_REF]. More specifically, decreases in detections of automation failures and increases in response times were evidence of complacency, as demonstrated in several studies [START_REF] Bagheri | Considering subjective trust and monitoring behavior in assessing automationinduced "complacency[END_REF].

The purpose of this study was to investigate the phenomenon of complacency with information automation. The design of human-computer interaction will also be proposed. With this research, we aimed to extend the studies on the reliability of automation by adding information automation and considering two levels of reliability (0 and 100%). Specifically, we compared two types of automation (action vs. information) and four levels of reliability of automation (0, 56.25, 87.5, or 100%). The level 0% represents a control condition without automation and 100% level represents perfect automation. The addition of these two levels allowed us to compare low and high levels of automation.

Our first hypothesis proposed an effect of the level of reliability on the time allocated to the automated task, suggesting that when reliability was high, the participants spent less time on the automated task [START_REF] Bagheri | Considering subjective trust and monitoring behavior in assessing automationinduced "complacency[END_REF]. Our second hypothesis proposed that performance (detection number) and reaction time were low when failures were not reported by information automation [START_REF] Rovira | Effects of information and decision automation on multi-task performance[END_REF]. Our third hypothesis was that mental workload score was higher when reliability was low [START_REF] Parasuraman | Performance consequences of automation-induced complacency[END_REF] 2 Method

Participants

Overall, 96 participants (69 women and 27 men) aged 18 to 27 years from the Institut National Universitaire Jean François Champollion participated in the experiment. They had no visual acuity problems.

Apparatus and materials

The Multi-Attribute Task Battery

The MATB [START_REF] Comstock | The multi-attribute task battery for human operator workload and strategic behavior research[END_REF][START_REF] Santiago-Espada | The multi-attribute task battery ii (matbii) software for human performance and workload research: A user s guide[END_REF]) is a microworld composed of several simultaneous tasks. A modified version named OpenMATB was used in this study. This micro-world comprises three tasks, a monitoring task consisting of four vertical gauges with a cursor fluctuating in each gauge. Sometimes, the cursor was stuck in the lower or the upper part of one of the gauges (indicating system malfunction) and the "warning" light changed to red (the top left in Figure 1). This was the focus of the experiment. The other two tasks consisted of a tracking task in which the participants had to keep a cursor in a target area (on top center in Figure 1) and a resource management task in which participants had to control a system of pumps to maintain two tanks (A and B) that were continually depleting at 2500 L (on the bottom center in Figure 1).

The tasks were performed on a standard computer. A joystick was used for the tracking task and a keyboard for the monitoring and the resource management tasks. Eye movements were recorded using an SMI Eye-tracker.

Figure 1. Screenshot of the OpenMatb

Design

The experiment focused on automation type (action automation vs. information automation) and automation reliability. Action automation related to the visualization of cursors of each gauge in the monitoring task. More precisely, successful action automation meant that the cursor unblocked itself when system malfunctioned. Conversely, when the action automation did not successfully fix a system malfunction, the participant had to manually unblock the cursor (with the F1, F2, F3, or F4 according to the malfunctioning gauge). Information automation related to a red warning light. More precisely, when information automation was successful, the light changed to red when a system malfunctioned. If the information automation were not successful, the light did not change red during the system malfunction when the action automation itself operated successfully.

Moreover, we manipulated four levels of automation reliability for each type of automation (0%; 56.25%; 87.5%; 100%). Automation was unreliable if it failed to correct or detect a system malfunction. The reliability corresponded to the percentage of the total number of failures detected and corrected by the automation. There were 16 failures in total per ten-minute block. Only the monitoring task was automated in our experiment. Each participant performed only one condition, being exposed to one level of information automation (between-subject) and all the levels of action automation (withinsubject). The action automation has been repeatedly supported with between-subject conditions [START_REF] Bagheri | Considering subjective trust and monitoring behavior in assessing automationinduced "complacency[END_REF]Singh, Sharma and Parasuraman, 2000). This study focused more on the automation of information; therefore, we chose this design. Moreover, we were limited by the number of potential participants.

Procedure

The different tasks of the MATB were first explained to the participants. Subsequently, 10 minutes were allotted to the training period, followed by 40 minutes allotted to the experiment. The experiment included four periods of 10 minutes that were counterbalanced (within-subject condition).

Measures

The first dependent variable was the time spent, as recorded with the SMI eye tracker at 1000hz. We previously defined the Area of Interest (AOI) as the different tasks of the MATB. Therefore, the time spent on each task was equivalent to the amount of time in each AOI.

The second dependent variable was the performance that was evaluated in each task. In the monitoring task, the number of detections/corrections of system malfunction ("hit") was recorded. In the tracking task, we recorded the proportion of time during which the cursor was located within the target area. In the resource management task, we recorded the average of the absolute differences from the target level (2500L) for the two main reservoirs (A and B).

The third dependent variable was the subjective measure. We used a computerized version of NASA TLX to assess mental workload [START_REF] Hart | Development of NASA-TLX (Task Load Index): Results of empirical and theoretical research[END_REF].

Results

Gaze behaviors

On average, the monitoring task was more supervised with low reliability of information automation (280 s at 0%, 270 s at 56.25%) than with high reliability (191 s at 87.5 and 157 s at 100%). A simple ANOVA showed a main effect of reliability of information automation of the time spent on the monitoring task, F(3,92) = 5.453, p <.01, η 2 = .151. Mean values for action automation were similar (57 s, 57 s, 54 s and 55 s for the level 0, 56.25, 87.5 and 100%). No effect was found for the reliability of action automation for the monitoring task, (p = .511).

For the tracking task, a simple ANOVA showed no effect of information automation on time spent on tracking task (p = .274). The mean values were higher for high reliability of information automation, but this result was not statistically significant (203 s, 221 s, 236 s, 242 s for the 0, 56,25, 87,5 and 100% levels). However, the effect for the action automation reliability was significant, F(3,92) = 3.939, p < .01, η 2 = .041. The mean values were 218 s, 220s, 229 s, 233 s for the 0, 56.25, 87.5, and 100% levels respectively. The participants spent more time in the tracking task when the reliability of action automation was high (on the monitoring task).

For the resource management task, the effect of the reliability of information automation on the resource management task was non-significant (p = .857). The mean values were similar (173 s, 173 s, 160 s, 174 s). However, a significant effect was found for the reliability of action automation on the time spent on the resource management, F(3,92) = 4.083, p <.01, η 2 = .042, with the means of 178 s, 168 s, 169 s, and 164 s.

Performance and reaction time 1.1.1 Performance

For the monitoring task, performance data was grouped into two categories: failures reported by information automation and failures that were not reported.

A repeated ANOVA showed the main effect of action automation on detection rate when failures were reported by information automation, F(3,71) = 8.234, p <.001, η 2 = .104. The mean performance values were .96, .97, .99, and 1 for the different reliability levels, respectively. A repeated ANOVA showed the main effect of action automation on detection rate when failures were not reported by information automation, F(3,71) = 61.60, p <.001, η 2 = .465. The mean performance values were.60, .82, .93, and 1 for the reliability levels, respectively.

For the tracking task, a repeated ANOVA showed no effect of information automation on performance (p = .965). The mean performance values were. 38, .38, .37, and .39 for levels 0, 56.25, 87.5, and 100%, respectively. However, the main effect of the reliability of action automation on the performance was significant, F(3,92) = 3.463, p <.05, η 2 = .036. The mean performance values were.37, .38, .39, and .39 for levels 0, 56.25, 87.5, and 100%, respectively.

Reaction time

A repeated ANOVA showed the main effect of reliability of action automation on reaction time when failures were reported, F(3,71) = 141,447, p < .001, η 2 = .666. The mean reaction times were 2,88 s, 1,86 s, 1,30 s, and 1 s for levels 0, 56.25, 87.5, and 100%, respectively. The main effect of reliability of action automation on reaction time when failures were not reported was significant, F(3,71) = 201,285, p < .001, η 2 = .739. The mean reaction times were 5.94 s; 3.29 s; 1.46 s and 1 for levels 0, 56.25, 87.5 and 100%.

Mental workload

A simple ANOVA showed no effect of information automation on the NASA TLX score (p = .194). The mean values were 5. 43, 5.34, 5.22, and 5.92 for levels 0, 56.25, 87.5 and 100%, respectively. A simple ANOVA showed no effect of the reliability of action automation, (p = .856). The mean values were 5.44, 5.48, 5.52, and 5.48 for levels 0, 56.25, 87.5, and 100%, respectively.

Discussion

Consistent with another study on action automation, information automation lead to a different allocation of visual resources to the secondary tasks (tracking and resource management). In accordance with other studies [START_REF] Oakley | Effects of automation reliability on human monitoring performance[END_REF][START_REF] Rovira | Effects of information and decision automation on multi-task performance[END_REF], our results suggest that information automation increases the performance and decreases the reaction time when failures are reported. When failures are not reported, the reaction time increases and the performance decreases. These results suggest that the participants developed a complacency with information automation. They missed the system malfunction when information automation failed, or their reaction to the system malfunctions was slower. Moreover, the automated task was less monitored (12.5%) compared to the other tasks (Tracking task 50%; Resource management 37.5%). Concerning the mental workload, we found no effect of automation on the NASA TLX score. We assume that the NASA TLX does not necessarily easily captures small changes in a long task [START_REF] Cegarra | The use of Tholos software for combining measures of mental workload: Toward theoretical and methodological improvements[END_REF]. Moreover, the participants did not receive any feedback which may lead to difficulty in assessing workload.

These results showed that the functions described by [START_REF] Parasuraman | A model for types and levels of human interaction with automation[END_REF] can lead to failures in cooperation between people and automation, like the phenomenon of complacency. This study is the first to investigate the phenomenon of complacency, and more studies on the topic are needed to increase our understanding of the complacency with information automation. Designers of the interface should be aware of possible failures in the human-machine interaction. The transparency of automation probably have to consider the role of complacency in futures studies [START_REF] Wright | Agent Reasoning Transparency: The Influence of Information Level on Automation Induced Complacency[END_REF].

Table 1 Reliability of both automations Level System malfunction corrected (action automation) or reported (information automation)

 1

	Total system malfunction

ACKNOWLEDGMENTS

This study was supported by ANR (ANR-16-CE26-0017) with the Smart Planning Project.

REFERENCE


Marco Raciti
email: marco.raciti@dariah.eu

Sally Chambers
email: sally.chambers@ugent.be

Rosário Jorge

Filipe Silva

Toma Tasovac

Dariah Ugent

Dariah Ugent Bcdh

Marco Raciti Dariah

Individual support to ESFRI and other world-class research infrastructures

Keywords: DESIR, DARIAH, General Assembly, Zagreb, Final Event D2

Executive Summary

The DESIR Final Event took place in Zagreb on 6-7 November 2019, alongside the DARIAH General Assembly. The DESIR Final Event brought together the whole consortium and involved several Bodies of the ERIC to maximise the impact of the event. The aim of the meeting was two-fold. First, it was to opportunity to summarise the activities conducted throughout the project and showcase results towards the DARIAH community. Secondly, it proposed a wider discussion over sustainability and funding models with National Representatives prior to the General Assembly.

Overall, 57 participants attended the event. The schedule has been structured to present the outcomes of each Work Package. As the project DESIR was divided into an evolving 6dimensional process, main results can be summarised as follows:

Dissemination and Innovation: the aim of this Work Package was to ensure a continuous dissemination of DARIAH service improvements, activities and research results within the relevant communities, academic stakeholders and other interested parties. Furthermore, the Work Package was in charge of organising main dissemination activities during the project and the DARIAH Beyond Europe workshop series (Stanford University, Library of Congress, National Library of Australia). Growth: this Work Package was concerned with the enlargement of the DARIAH membership targeting six countries (Czech Republic, Finland, Israel, Spain, Switzerland, United Kingdom). Membership could only be achieved in Czech Republic, the application was submitted and ratified by the General Assembly in November 2019. Nevertheless, in other countries, collaboration with DARIAH has been greatly strengthened and significant progress regarding DARIAH membership has been achieved. Technology: the Work Package delivered three demonstrators focused on bibliographical metadata. The demonstrators show the usage of tools for bibliographical metadata in various stages of the research process, e.g. extraction of entities, the collection and sorting of citations, visualisation of selected aspects of the data. These demonstrators were built with the involvement of the community of researchers through two Code Sprints organised in Berlin. CESSDA; finally a renewed business plan building on existing strategic documents was developed.

Trust: this Work Package contributed to DARIAH's long-term sustainability by measuring acceptance and impact of DARIAH in new cross-disciplinary communities and core groups through a survey, in-depth qualitative interviews and strategic meetings. The analysed information collected from each source led to a recommendations and community engagement tool developed to share and translate the recommendations dataset for a broader audience.

Teaching: the work carried out during the course of the project led to the implementation of a discovery framework and hosting platform for DARIAH learning resources, DARIAH-Campus. The platform was officially launched during the event. The goal of DARIAH-Campus is to widen access to open, inclusive, high-quality learning materials that aim to enhance creativity, skills, technology and knowledge in the digitally-enabled arts and humanities. The organisation of a final event is described in task 2.4 of the project with the aim of presenting final reports of the Work Packages as well as strategies for DARIAH sustainability beyond the project lifetime. Originally, the final event was planned to be held in December 2019 in Paris. Nevertheless, the Consortium believed that organising the final event alongside the annual face-to-face DARIAH General Assembly would maximise the impact of the event. Therefore, the DESIR Final Event took place on 6-7 November 2019 at the Rectorate of the University of Zagreb, Croatia. The event was preceded by the DARIAH National Coordinators Committee (NCC) meeting and followed by the DARIAH General Assembly. Due to the seating capacity of the venue, the registration of the event could not be publicly opened. Invitations to the event have been sent to DARIAH National Coordinators, DARIAH National Representatives, project partners and members of the DARIAH-HR consortium. The attendance on the first day was 51, while on the second day the number of participants was 50 with a slightly different composition in comparison with the day before. In total, 57 participants attended at least one day of the DESIR Final Event.

The aim of the event was two-fold: the first day focused on presenting the results of the project to the audience through a detailed description of the activities of each Work Package. The agenda of the second day included two presentations on sustainability and funding models: the first focused on the notion of valuing and sharing knowledge in arts and humanities, while the second took the point of view of the NCC to launch a reflection on how to optimise national and European SSH Research Infrastructure investment. The idea was to involve DARIAH National Representatives in the discussion with the purpose of gathering important input for fine-tuning strategies for DARIAH's medium and long-term sustainability. Later on, the General Assembly generated one important outcome of the project when it approved the Czech Republic as the19 th Member of DARIAH.

Despite the name of the event, not all project activities were completed at that time (for example a final version of the Business Plan, some training measure in accession countries and the Winter School in the framework of Work Package 7: Teaching). Hence, supplementary communication activities will be deployed to promptly inform DARIAH Bodies and stakeholders of full project's results.

PART 1 -6 November 2019

The first day of the final event was devoted to showcase the results of the project, notably to DARIAH national coordinators who had met in the morning. Establishing a fruitful communication with the National Coordinators Committee is crucial for DARIAH to ensure mutual exchange between the national and European levels.Toma Tasovac introduced the key challenges of the project which were built upon DESIR's 6 core infrastructural sustainability dimensions: the ability to disseminate information and knowledge to users, grow the community of users, augment the offer of services with state-of-the art technologies, ensure robustness of the governance, gain trust from its users and communities, build access to education and training.

Work Package 2: Dissemination

Sally Chambers (UGENT), Work Package 2 leader, gave a description of the activities undertaken during the last three years of work. The objectives of Work Package 2 could be summarised in four points:

1. Organise the DESIR kick-off event in Berlin 2. Ensure a continuous dissemination of DARIAH service improvements, activities and research results within the relevant communities, academic stakeholders and other interested parties; 3. Host three international workshops in the US and Australia to raise DARIAH's profile; 4. Organise the final DESIR event in Paris.

The DESIR kick-off meeting took place on 25 April in Berlin alongside the DARIAH Annual Event to reach a wider audience and maximise the impact towards DARIAH communities and beyond. The topic was extremely relevant to DESIR as the DARIAH Annual Event 2017 focused on the subject of sustainability of Research Infrastructures. The kick-off event was an important occasion to bring together the whole consortium, facilitate networking and successful cooperation throughout the project lifetime. The successful organisation of the meeting led to the submission of deliverable D2.1 DESIR Kick-Off Meeting Report1 which reported in detail all presentations and outcomes of the event. Task 2.2. focused on disseminating DARIAH and DESIR activities in order to make the project findings available to the DARIAH community and to the wider public. In terms of external communication, the objectives of this task were to make DESIR achievements visible and accessible, raise awareness of DARIAH (e.g. nationally, in Europe, internationally), address stakeholder groups specifically with key messages (e.g. DESIR partners, DARIAH Members and future members, arts and humanities researchers) and monitor dissemination activities. A dissemination and monitoring compliance strategy was produced at the beginning of the project in deliverable D2.2 DESIR Dissemination Strategy Report. Dissemination activities and communication tools (such as conferences, articles, blog posts, posters, tweets) have been listed. An extensive monitoring report has been produced for the first reporting period and will be updated for the final periodic report. To present activities and latest news of the DESIR project, various means of communications have been used. The DARIAH website2 includes a dedicated page3 in which basic information about the project can be found (duration, partners, contribution, topic, summary), as well as public deliverables, major results and activities. All project related news are also tagged for easy retrieval. Information about the DESIR project can also be found on partner websites4 . Regular updates are also given to subscribers of the DARIAH newsletter issued monthly. Public deliverables are also uploaded to the open archive HAL5 . DESIR and DARIAH have also been presented to several conferences and workshops. Recently, two posters and have been presented to the DH2019 Conference in Utrecht, the major event in Digital Humanities with more than a thousand participants. The organisation of three international workshops was an important building block of the Work Package. These workshops served as fora for cross-cultural exchange and introduced many non-European DH scholars to DARIAH; each of the workshops included a significant delegation from various DARIAH bodies, together with a larger number of local presenters and participants. The local contexts for these workshops were significantly different in their embodiment of research infrastructures: on the one hand, in the U.S., Stanford University and the Library of Congress, both in a country with a with a history of national infrastructural challenges; and in Australia, which has invested substantially in coordinated national research infrastructure in science and technology, but very little on a national scale in the arts and humanities.

The Stanford workshop had four main topics of focus: corpus management; text and image analysis; geohumanities; and music, theatre, and sound studies.

The main theme of the Library of Congress workshop was "Collections as Data," building on a number of U. digital collections through computationally-driven research. Knowledge exchange sessions focused on digitised newspapers and text analysis, infrastructural challenges for public humanities, and web archiving.

In late March 2019, DARIAH organised the third DARIAH beyond Europe event in conjunction with the second annual Humanities, Arts and Culture Data Summit at the National Library of Australia in Canberra. This three-day event included several panel discussions and presentations on topics such as the sustainability of digital projects, crossfertilisation of research and knowledge exchange on infrastructures in Australia and Europe.

A research blog 6 to report on the DARIAH Beyond Europe workshops has been opened on hypotheses.org 7 , a platform that hosts several thousand blogs covering all areas of the humanities and social sciences. Individual pages were set up for each workshop with a description of the program, keynotes, registration and practical information. The blog also redirects to the community notes of each workshop, taken collaboratively by participants, and provides links to videos of the events. The University of Haifa worked nationally towards the establishment of a Consortium and awareness-raising initiatives. In this respect, particularly important were the "DARIAH-IL" event held on 7 October 2018 which provided a starting point for a national consortium, the collaboration with the "Young Academy of Israel" and a training workshop "Introduction to Text Encoding and Digital Editions" that took place on 24 October 2019 in Haifa with the participation of Toma Tasovac and Sinai Rusinek. This event was preceded by a meeting between Toma Tasovac, on behalf of the Board of Directors, and the Israeli representative in charge of the humanities and the social sciences at the Ministry of Science and Technology.

The situation in Spain was presented by Salvador Ros, Maurizio Toscano and Aroa Rabadán Reyes. The political and financial situation in Spain has been particularly challenging during the course of the project. Nevertheless, UNED managed to achieve considerable progress on the road to Spanish DARIAH membership. UNED carried out a study to describe the current state of digital research infrastructures in the field of arts and humanities in Spain in order to promote DARIAH membership in Spain. The aim is to write a report, in the format of a white paper, to provide a greater understanding of the current Spanish scenario considering the withdrawal of the United Kingdom from the European Union, known as Brexit, nevertheless, the Consortium is growing steadily. From two Cooperating Partners in 2016, the United Kingdom grew to 6 in 2016: Glasgow University, King's College London, Lancaster University, University of London, Swansea University, University of Exeter.

From the beginning of the project, one of the objectives was to involve key stakeholders. As a consequence, a workshop to discuss the Digital Humanities landscape in the UK and a strategic meeting were organised respectively in London and Glasgow. The UK DESIR partners have been in ongoing engagement with policy makers (primarily UKRI and AHRC) on the emerging UK national roadmap for research infrastructures. which conditions apply and for what purposes and data it is useful. The report showed also that there is a large demand in the DH community for comprehensive information, which is currently being addressed by the project SSHOC 10 . Ultimately, the gap analysis led to the decision of working on bibliographical data and the enhancement of already existing services revolving around this topic. The services chosen after the gap analysis were the following:

• GROBID 14 for text mining: GROBID is a machine learning library for extracting, parsing and re-structuring raw documents such as PDF into structured XML/TEI encoded documents with a particular focus on technical and scientific publications.

• BibSonomy 15 for scholarly content management: BibSonomy is a social bookmarking and publication-sharing system. It aims to integrate the features of bookmarking systems as well as team-oriented publication management.

• VisNow/VIStory 16 for visualisation: VIStory is a tool for visualisation of processed data with added dimensions for journals, topics, or dependency graphs.

During the course of the project two Code Sprints were organised.

Work Package 5: Robustness

The key objective of this Work Package, presented by Yoann Moranville (DARIAH) and Sally Chambers (UGENT), was to increase the sustainability of DARIAH, not only by broadening the geographical and diversified community reach of DARIAH, but also by augmenting its organizational structure through the development of a business plan, a centralised helpdesk and the development of requirements for a marketplace.

Yoann Moranville outlined the process that led to the implementation of a centralised helpdesk. The idea was to replace the current contact form in the DARIAH website. The helpdesk, built with the help of CLARIN-D (the German node of CLARIN ERIC), will be the main entry point to provide users with a personalised support service. The helpdesk is currently structured around 7 categories: General, Education and Training, Join DARIAH, Open Science, Technical Issues, Tools and Services, Working Groups. A person responsible for each category has been appointed. It is based on OTRS22 , a ticketing system, to ensure an organised, efficient and centralised mechanism to support user requests. A potential use in the near future would be to link the helpdesk with the marketplace to handle related user requests. The marketplace is currently being developed in the framework of Work Package 7 of the Horizon 2020 funded project SSHOC. The objective of task 5.5 was to prepare the ground for the SSHOC Consortium (before the kick-off of the project) by providing elements of discussion. In particular, in DESIR, partners focused on the contextualisation of solutions (tools, services, learning and teaching materials, datasets, repositories), an overview of the current landscape (including TERESAH 23 , TAPoR 24 , DiRT In the broadest sense, DARIAH's core audience is arts and humanities researchers in Europe and beyond who are interested in using digital methods, data and tools in their research and teaching, based on an inclusive approach.

Efforts to visualise the DARIAH community have been made and one of the objectives is to stimulate a virtuous circle between DARIAH members and DARIAH-EU National communities.

In conclusion, the current landscape of Research Infrastructure is becoming crowded and the find solutions to optimise National & European Investment is crucial for the future sustainability of the ERIC.

An initial draft of the Business Plan was submitted to the European Commission in December 2018, which was iteratively developed as a "living document" by the Business Plan team throughout 2019, prior to the final submission by the end of December 2019. As a first step, an outline of the survey was provided in deliverable D6.1 Prepare for the DESIR kick-off event in order to measure trust of three cross-disciplinary communities in the DARIAH network (organisational perspective), the DARIAH membership base (individuals) as well as infrastructure and services (offer). The document described the aims and scope of the experimental survey, defined its methodological approach and presented an outline of the questionnaire.

Work

A survey was conducted from 11 January to 18 April 2018 and targeted researchers, professors, MA and PhD students within the arts and humanities community, users and potential users of Digital Humanities infrastructures, from universities or other research institutions, with or without any permanent institutional affiliation. Afterwards, the first step of the survey data treatment and analysis was the data validation and codification of the answers. Next, the analysis used the statistical techniques, allowing the quantitative univariate, bivariate and multivariate analyses. In total, 506 questionnaires were taken into account to the data analysis.

The survey gave insights on the characterization of the DARIAH use and socio-professional characterization of the users. The survey showed for example the low use of infrastructures within early-career researchers and the fact that the use of DH infrastructures or DARIAH is more associated with cross-disciplinary approaches. A report on the survey, D6.2 Empirical investigation of trust, gender and diversity in crossdisciplinary DARIAH communities, has been delivered in June 2018.

With the purpose of providing proposals and policy recommendations in view to a sustained growth of DARIAH, WP6 partners conducted individual interviews with key informants in three levels of decision-making:

• Regular users of digital humanities;

• Institutional decision-makers (universities, research units, cultural heritage organizations); • National decision-makers (funding agencies, national infrastructures managers).

To represent the geographical coverage of DARIAH, interviews were conducted in Portugal, Germany and Croatia. Another layer of information was given by continuous exchanges with DARIAH Bodies and in particular the National Coordinators Committee (NCC). Content can be browsed through categories such as resources, events and pathfinders, a collection of external learning resources, curated and contextualized by the DARIAH team. Users can also browse learning resources based on their topic. In addition to DARIAH-Campus, a template for capturing events for the benefit of those who could not attend is also proposed. For this purpose, the example of a synthesis template prepared for a Winter School36 organised by DARIAH and CNRS in 2016 in the framework of the Humanities at Scale project has been adapted and updated. 2.7 Keynote: "Cultural Innovation, a notion taken for granted", Riccardo Pozzo.

The concluding session of the meeting was dedicated to a keynote speech delivered by Riccardo Pozzo, Professor at the University of Roma Tor Vergata and Chair of the DARIAH Scientific Board 39 . The inspiring keynote focused on how building stable research infrastructures and innovation can go hand in hand and how we can define cultural innovation.

The term cultural innovation has been used for creativity, marketing and migrations, however, there are currently no agreed definitions of cultural dimensions of innovation.

If we look back at history, we perceive different models of innovation: first of all, a linear model of innovation in which innovation is conceived as new products and new processes that encompass some novel technological step. In this model a prototype would eventually become a product, stopping the research phase and generating what we could call a "knowledge to money" process. Later, this model has been criticised in favour of a chain model of innovation in which innovation is seen as a recursive chain in which technology can also pull science towards specific problems and domains, which eventually are translated into innovation in the market as products. In recent times, open innovation has been described as a collective process aimed at generating innovation. In this case, innovation is not only seen as a process needed to create market-oriented products in order to make a profit, but rather as a creation of services that bring costs down.

There is a recurrent question that concerns the arts and humanities area: how is innovation possible?

In order to describe the cultural dimensions of an innovation in public spaces, a first step is to have a look at social innovation. Social innovation takes place when a new product answers the following questions: 39 https://www.dariah.eu/about/organisation-and-governance/#scientific-board DARIAH is a special platform where knowledge comes together, happens and it's shared. However, in the context of digital humanities challenges grow in complexity. In October 2003, UNESCO adopted the Charter on the Preservation of Digital Heritage40 , which consists of unique resources of human knowledge and expression. Among the challenges addressed by the Charter the following need to be mentioned: the access to digital heritage, the fair balance between the legitimate rights of creators and the interests of the public to access digital heritage materials, the risk of losing world's digital heritage to posterity and the attitude of institutions and governments that have been faced too rapidly with the digital evolution to develop timely and informed preservation strategies.

Much has been achieved thanks to the digital humanities but there is still a lot to do. Collaboration is key for the reliable preservation of digital heritage and the safeguarding of memory. The organisation of digital heritage requires multidisciplinary work. Furthermore, the development of digital skills and training is decisive to address these challenges. The inclusion of courses and university curricula is still very limited nowadays. Furthermore, one of the findings of the survey conducted in the framework of Work Package 6 is that the use of digital infrastructure is very low in the case of early-career researchers. There can be a huge gap between knowledge, available training and on the other hand lack of access to those who do not have the means for preserving and guarding against loss of heritage. The role of digital infrastructure and digital humanities in general is to contribute to the development of awareness and training.

The role of Open Science is also crucial for preserving information, sharing knowledge, democratising access and contributing to building a fairer society. Open Science unblocks a new scientific process of production and use of knowledge as a whole, but it requires a cultural change. -KEY RECOMMENDATION #1 Promote research excellence with inclusive, collaborative, bureaucracy free and community-driven approach.

-KEY RECOMMENDATION #2 Ensure the integration of tools, services, data and resources within DARIAH community and with other Research Infrastructures (e.g. by gathering them on a platform such as the Marketplace). -KEY RECOMMENDATION #3 Foster a collaborative learning environment and anticipate the skills of the future through a joint strategy for education and training (e.g. DARIAH-Campus).

-KEY RECOMMENDATION #4 Establish a flexible, participatory and effective governance model with a clear and sustainable business plan.

-KEY RECOMMENDATION #5 Strengthen DARIAH's representation in European and International policy arena, expanding its visibility and cooperation outside EU borders.

-KEY RECOMMENDATION #6

Broaden and extend DARIAH's role, action and benefits towards the strengthening of scientific citizenship in Europe.

-KEY RECOMMENDATION #7

Set up means for monitoring and bringing communities together, while respecting diversity on an institutional, scientific, disciplinary and methodological level.

In conclusion, the sustainability of DARIAH should be guaranteed by its quality. Three areas of action are therefore crucial in this respect:

1. Stimulate, inspire, help young researchers to make science; 2. The relationship with society is crucial (citizen science, shared science). Improving the visibility of arts and humanities is extremely important and DARIAH should play an advocacy role, e.g. by defining positions, commenting, producing recommendations and advocating best practices; 3. Make science happen. able to bring in at European level through funded projects and other initiatives. One of the issues when we look at the DARIAH community, which is composed of 19 countries, 152 partner institutions, 352 Working Group members and a great number of stakeholders, is how to efficiently mobilise the network.

"Optimising

The perspective from the point of view of the Ghent Centre of Digital Humanities (GhentCDH) 41 gives a perfect example of the challenges for securing funding on the national level. The funding structure in Belgium is particularly complex and funding is available at many different levels. Looking at the Flemish side of Belgium, Research Infrastructure funding is available for access to medium-scale RIs, large-scale RIs and international RIs. Furthermore, at GhentCDH, successful projects have received funding from European Research Council (ERC) Starting Grants and through the research programme BRAIN-be (Belgian Research Action through Interdisciplinary Networks). Also, international collaborations open up new funding possibilities. With the purpose of increasing SSH funding at European level, a SSH Working Group has been formed at Ghent University to help and provide feedback to policy-makers and play an advocacy role. Such an effort would be particularly useful for DARIAH if replicated in other countries.

In conclusion, the SSH research infrastructural landscape is becoming crowded with new initiatives on the ESFRI 42 roadmap. Nevertheless, there is a need for DARIAH to collaborate with them in the most effective way. It is extremely important at NCC level to work closely together. Furthermore, a stronger collaboration between the NCC and the DARIAH General Assembly is necessary in order to optimise a financial and sustainable future for DARIAH.

Conclusion

The presentations were followed by a brief discussion and debate with the National Representatives. One recurring question focused on the complex and dense Research Infrastructure landscape in Social Sciences and Humanities and how DARIAH is strategically dealing with it. Nevertheless, this crowded landscape should be seen as an opportunity for collaboration rather than competition. DARIAH has strengthened links with CLARIN, E-RIHS, CESSDA and several other Research Infrastructures. To run a sustainable infrastructure and fruitfully contribute in such an overcrowded landscape, it will be necessary to work on specific workflows overseen by different Research Infrastructures and consolidate the expertise.

An interesting comment from the crowd reflected on the question of proposing a clear set of impact indicators and also to advocate toward ESFRI the specificities of Social Sciences and Humanities and propose new impact concepts which are more appropriate to SSH Research Infrastructures. The internal DARIAH Strategic Meeting that will take place in January 2020 will be partly dedicated to this issue.

The recommendation tool developed in the context of Work Package 6 led to some questions from the crowd, in particular about the next steps needed for implementing the outcomes of the policy recommendations. Preliminary work has already been done in the framework of the NCC and some recommendations are part of the DARIAH Strategic Actions Plan. The recommendations reflect the current situation and there is a will in DARIAH to continue working collaboratively to adapt recommendations to future challenges. The tool will help DARIAH in shaping its policy and prioritise actions.

The question of funding was also discussed. The Social Sciences and Humanities are fragmented fields, but they have learned to be very creative. The challenge for DARIAH will be to explain what Social Sciences and Humanities are and what disciplines are underneath. A suggestion from the crowd would be to focus on a limited number of key projects rather than dispersing efforts to run many projects with a limited scope. Furthermore, cultural frameworks should be the main focus of funding for DARIAH.

Overall, we consider the DESIR Final Event as successful. The project per se is an important building block towards a mature and operational infrastructure. Therefore, presenting the outcomes of the project to many DARIAH stakeholders had certainly raised the profile and increased the impact of the event.

  DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

  Robustness: the aim of this Work Package was to strengthen the organisational structure of DARIAH. The activities undertaken had a multifaceted nature: the relationship with the user community was improved through the implementation of a centralised helpdesk; preliminary work towards the Marketplace was conducted; the EURISE Network (European Research Infrastructure Software Engineers' Network) was established with CLARIN and DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

  members of the consortium (including the Commission Services) EU-RES Classified Information: RESTREINT UE (Commission Decision 2005/444/EC) EU-CON Classified Information: CONFIDENTIEL UE (Commission Decision 2005/444/EC) EU-SEC Classified Information: SECRET UE (Commission Decision 2005/444/EC) Disclaimer DESIR has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 731081. This publication reflects the views only of the author, and the Commission cannot be held responsible for any use which may be made of the information contained therein. Introduction DESIR, DARIAH-ERIC Sustainability Refined, is a 3-year project (1 January 2017 -31 December 2019), funded as a Coordination and Support Action (INFRADEV-03-2016-2017) under the European Commission's Horizon 2020 Programme. Coordinated by DARIAH-EU, the DESIR consortium includes 16 partners from 12 countries (Belgium, Czech Republic, Finland, France, Germany, Israel, Poland, Portugal, Serbia, Spain, Switzerland and the United Kingdom). The aim of DESIR is to strengthen the sustainability of DARIAH, Digital Research Infrastructure for the Arts and Humanities, and firmly establish it as a long-term leader and partner within arts and humanities communities.

Figure 1

 1 Figure 1 Toma Tasovac and Marco Raciti introduce the event

  DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081. Part 2 -Discussion with the DARIAH General Assembly, 7 November, Rectorate of the University of Zagreb 09:00 -09:15 Welcome & Introduction 09:15 -09:45 "Towards a Sustainable DARIAH: valuing and sharing knowledge in arts and humanities" 09:45 -10:15 Optimising National and European SSH Research Infrastructure Investment 10:15 -10:30 Discussion DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

  DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

  S.-based initiatives exploring how to enhance researcher engagement with DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

Figure 2

 2 Figure 2 Sally Chambers presents Work Package 2

Figure 3

 3 Figure 3 Martin Lhotak introduces the activities of DARIAH-CZ

  . The study allowed to map researchers, research projects, tools, resources, training courses, bibliography and journals in Spain. Claire Clivaz of the Swiss Institute of Bioinformatics (SIB) briefly explained the situation in Switzerland. The construction of DARIAH-CH has been progressing steadily since 2013. The first cooperating partners in DARIAH were accepted in 2015 and the consortium now counts 9 institutions (University of Basel, University of Bern, University of Geneva, University of Lausanne, University of Zurich, Swiss Academy of Humanities and Social Sciences, Swiss Institute of Bioinformatics, École polytechnique fédérale de Lausanne, University of Neuchâtel). According to the new position expressed by the State Secretariat for Education, Research and Innovation (SERI), Swiss full membership in smaller ERICs like DARIAH could be discussed only during the period 2021-2024. A potential observer membership could be explored in 2021. Within DESIR, a DARIAH-CH workshop took place in Neuchâtel on 29-30 November 2018 8 . A training workshop "Sharing the experience: Workflows for the Digital Humanities" was held at the University of Neuchâtel on 5-6 December 2019 9 . Arianna Ciula, Deputy Director at King's Digital Lab, outlined the activities towards accession of the United Kingdom in DARIAH. Even though the political situation is not ideal DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

•

  Another activity was coordinated by the newly hired King's Digital Method Lead to include a Research Software Engineering training in DARIAH-Campus (see Work Package 7) and organise an advanced training workshop on Research Software Engineering and Digital Humanities on 9 December 2019. 2.3 Work Package 4: Technology On behalf of Work Package 4: Technology, Work Package leader Stefan Buddenbohm from the University of Göttingen reported on tasks carried out during the course of the project. Alongside the University of Göttingen, the WP4 team consists of ICM (Interdisciplinary Centre for Mathematical and Computational Modelling at the University of Warsaw), L3S (Research Center L3S at Leibniz University Hannover), INRIA (French Institute for Research in Computer Science and Automation) and DARIAH. The objectives of this Work Package were to: • Ensure DARIAH's long-term sustainability by technologically enhancing its research infrastructure and services • Shape DARIAH's profile in four technology areas: -entity-based search -scholarly content management -text analytic services -visualisation Coordinate the overall technological contribution to DARIAH. The first step was to carry out a gap analysis of the DARIAH Research Infrastructure. The task was intended as a gap analysis to identify potential community requirements for services. The study showed 82 different services ranging from basic infrastructural components to very specialised research tools. However, for a significant number of resources, the issue was to determine whether the service is maintained, how it can be used, DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

  DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

  Package 6: Trust Filipe Guimarães da Silva, Inês Castaño, João Fernandes and Maria do Rosário Jorge from NOVA University Lisbon, Faculty of Social Sciences and Humanities, outlined the work carried out in the content of Work Package 6: Trust. The objectives of this Work Package are to measure trust in cross-disciplinary DARIAH communities and new core groups, develop strategies to increase confidence in DARIAH's services and infrastructure and enlarge DARIAH by engaging new cross-disciplinary communities.32 European Science Foundation (2011). ESF Science Policy Briefing 42, Research Infrastructures in the Digital Humanities, Strasbourg, pag. 2. 33 Schreibman, S., Siemens, R. G., Unsworth, J. (2016). A new companion to digital humanities, John Wiley & Sons, Ltd. DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

  DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

Figure 4

 4 Figure 4 Screenshot of the Recommendations and community engagement toolThese activities led to a Recommendations & community engagement tool, available online for the DARIAH community 34 , in which data can be sorted out and filtered to visualise recommendations. This tool could be intended as a community service in DARIAH to streamline priorities and action plans. The last document D6.3 Policy recommendations and strategy report is expected to be submitted in December 2019.

Figure 5

 5 Figure 5 Screenshot of the DARIAH-Campus website

Figure 6

 6 Figure 6 Riccardo Pozzo

  Towards a Sustainable DARIAH: valuing and sharing knowledge in arts and humanities", Maria Fernanda Rollo Maria Fernanda Rollo, Professor and Coordinator of the Doctorate in History, Archeology and Documentary Sciences in the Faculty of Social Sciences and Humanities, NOVA University of Lisbon, gave an inspiring presentation based on the results of Work Package 6: Trust.

  DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081. Knowledge production is continuously changing and Research Infrastructures have a vital role in supporting research but they have to reinvent themselves. The DARIAH Strategic Plan for the next 7 years is an important step towards this direction. The work in DESIR was strategic in DARIAH's sustainability in order to measure the impact and excellence of DARIAH and how to increase trust. It represented a unique opportunity to engage transparently with the community. Work Package 6 used several sources to draw a set of recommendations. A survey addressed to users and potential users was launched in 2018 and individual interviews with policy makers and DH researchers have been collected in Germany, Croatia and Portugal. Furthermore, Work Package 6 members had the chance to exchange with DARIAH Bodies throughout the project. Data has then been processed analytically to suggests key strategic and mission-oriented recommendations:

Figure 7

 7 Figure 7 Rectorate of the University of Zagreb

  National and European SSH Research Infrastructure Investment", Sally Chambers Sally Chambers, Work Package 2: Dissemination and Innovation leader and Chair of the DARIAH National Coordinators Committee (NCC), gave a presentation on how to optimise national and European Research Infrastructure investment in the Social Sciences and Humanities. The role of the General Assembly is crucial in this context to further strengthen the work already undertaken. The business plan is an important document in this respect. It will guide the discussion on how DARIAH can bring value to its members. Several dimensions should be taken into account. One aspect is the calculation of the additional funding that the infrastructure is D2.4 Organise DESIR final event½page 30 DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

  41 https://www.ghentcdh.ugent.be/42 The acronym stands for European Strategy Forum on Research Infrastructures. This strategic instrument was formed in 2002 at the behest of the European Council and it supports a coherent and strategy-led approach to policy making on Research Infrastructures in Europe

Figure 8

 8 Figure 8 Presentation given by Sally Chambers

  The whole activity led to deliverable D4.1 Gap Analysis of the DARIAH research infrastructure 11 .Another recurrent issue concerns research software sustainability in terms of quality and reusability. The aim of this task was to create a DARIAH Technical Reference, which later became a coordinated effort of three ERICs, CESSDA, CLARIN and DARIAH under the umbrella of the EURISE Network 12 . The EURISE Network Technical Reference is a collection of basic guidelines and references for development and maintenance of infrastructure services. An associated deliverable has been submitted in June 2018: D4.2 Conceptual Models of Integration of New Services 13 .

  The first one took place in Berlin from 31 July to 2 August 201817 . The event focused on bibliographical and citation metadata and was divided into four tracks: extraction from PDF with GROBID; management with BibSonomy; visualisation with VisNow and an extra track on bringing services into the 's Single Sign-On, AAI (Authentication and Authorisation Infrastructure). Following the success of the first Code Sprint, the Consortium decided, following the suggestion of the mid-term project review report, to plan a second event during the second half of the project. The second Code Sprint on Bibliographical Metadata was organised at the Forum Factory in Berlin on 24-26 September 201918 . The event had the objective of enriching GROBID functionalities by adding a parser for acknowledgment for raw text and PDF files19 , extend BibSonomy for the automatic import of bibliographic data 20 and extending VIStory with time dependent graphs of relations with new data formats and use cases 21 .During one of the coffee breaks at the DESIR Final Event, participants had the possibility to test main functions of demonstrators. Demo session have been conducted by Yoann Moranville (DARIAH) for GROBID, replacing Tanti Kristanti (INRIA) who was unable to attend the meeting, Christoph Hube (L3S/Leibniz University of Hannover) for BibSonomy and Bartosz Borucki for VIStory.

10 https://sshopencloud.eu/ 11 https://halshs.archives-ouvertes.fr/hal-01663594 12 European Research Infrastructure Software Engineers' Network: https://eurise-network.github.io/ 13 https://halshs.archives-ouvertes.fr/DARIAH/hal-01825919v1 14 https://grobid.readthedocs.io/en/latest/Introduction/ 15 https://www.bibsonomy.org/ 16 http://vistory.icm.edu.pl/ (under development) 17 Documentation is available here: https://desircodesprint.sciencesconf.org/resource/page/id/7 DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081. DARIAH

  Task 5.2 had the objective of organising at least one workshop exploring generic challenges for RIs in order to learn about best-practice examples. Initially, the focus area concerned funding, governance and structure of DARIAH. However, to avoid duplication of efforts with the newly formed ERIC Forum 28 , the Consortium decided to connect this task with Work Package 4 and rather concentrate on technology and in particular software development. the digital arts and humanities and could be addressed by DARIAH were identified. The document formulates a value proposition for DARIAH and describes the current user communities and potential and/or future users. However, an important starting point, is also to define what a humanities (data) infrastructure is. A peer-reviewed publication of the Science Policy Briefing (SPB) on "Research Infrastructures in the Digital Humanities", published in September 2011 reflected on "the centrality of Research Infrastructures (RIs) to the Humanities" and claimed that "without Research Infrastructures (RIs) significant strands of Humanities research would not be possible" 32 . To cite Jennifer Edmond "a more useful approach to defining infrastructure, therefore, is to capture not what it is, but what it does; or to be more exact, how it does what it does. Real infrastructure, when it is working properly, disappears from view" 33 .

	25 , EOSC-Hub Marketplace 26 ) and
	identification of common functionalities, development of user stories, description of
	requirements. Furthermore, mockups have been created by a UX designer. As a result of
	these activities, D5.4 Develop a centralized helpdesk and marketplace mockup was
	submitted in March 2019 27 .
	23 http://teresah.dariah.eu/
	24 http://tapor.ca/home
	25 https://digitalhumanities.berkeley.edu/projects/dirt-digital-research-tools
	26 https://marketplace.eosc-portal.eu/

The first workshop "Software Sustainability: Quality and Re-usability" was held in Berlin on 9-10 October 2017. During the workshop, CLARIAH-NL Software Quality Guidelines, CESSDA Software Maturity Model, and DARIAH-DE Service Life Cycle were presented. The meeting led to the creation of the EURISE Network. An additional workshop "Software Sustainability within Research Infrastructures" took place on 12-13 March 2019 in Utrecht. A detailed report of the workshop was submitted in the framework of deliverable D5.1 Workshop with research infrastructures

29

. Sally Chambers introduced the business plan developed in the context of task 5.3. A business plan in the context of DARIAH should take into account the financial sustainability of the infrastructure, its value and how it can bring value to its members. Furthermore, the business plan should be complementary to other DARIAH strategic documents such as the Strategic Plan 30 , Strategic Action Plan (STRAPL), Statutes 31 , Internal Rules of Procedures etc. Ideally, such a document should situate DARIAH at present and outline where the infrastructure shall be in 3-5 years-time. A number of scientific challenges and gaps that 27 https://hal.archives-ouvertes.fr/hal-02088278 28 https://www.eric-forum.eu/ 29 https://hal.archives-ouvertes.fr/hal-02081139 30 https://www.dariah.eu/wp-content/uploads/2019/08/Strategic-Plan_2019-2026.pdf 31 https://www.dariah.eu/wp-content/uploads/2019/03/DARIAH-ERIC_Statutes_March2019.pdf DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081. affect

https://www.dariah.eu/wp-content/uploads/2017/03/20170630_DESIR_D2.1_DESIR_Kick-off_Meeting_Report_final.pdf

https://www.dariah.eu/

https://www.dariah.eu/activities/projects-and-affiliations/desir/

Some examples: University of Göttingen (https://www.sub.uni-goettingen.de/en/projectsresearch/project-details/projekt/desir/), King's College (https://www.kdl.kcl.ac.uk/our-work/dariahdesir/), Ghent University (https://www.ghentcdh.ugent.be/projects/desir-dariah-eric-sustainability-

refined-0) 5 https://hal.archives-ouvertes.fr/

https://www.unine.ch/dariah-ch/home/keynotes.html

https://www.dariah.eu/2019/07/15/dariah-ch-workshop-2-sharing-the-experience-workflows-for-thedigital-humanities/

https://desircodesprint.sciencesconf.org/

https://github.com/DARIAH-ERIC/DESIR-CodeSprint-TrackA-TextMining

https://github.com/DARIAH-ERIC/DESIR-CodeSprint-TrackB-BibliographicMetadata

https://github.com/DARIAH-ERIC/DESIR-CodeSprint-TrackC-Visualization

Open-source Ticket Request System: https://otrs.com/.

https://dariah.peopleware.pt/

https://campus.dariah.eu/

https://campus.dariah.eu/resource/ws2016

UNESCO (2003): Charter on the Preservation of Digital Heritage, URL: http://portal.unesco.org/en/ev.php-URL_ID=17721&URL_DO=DO_TOPIC&URL_SECTION=201.html

submitted D2.4 Organise DESIR final event½page DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081. DESIR INFRADEV-03-2016-2017 -Individual support to ESFRI and other world-class research infrastructures, Grant Agreement no. 731081.

An example of successful social innovation is the regional healthcare card introduced by Region Lombardy in 1999, as it solved the problem of providing access to data, enabled substantial savings and was universally accepted. However, cultural innovation, while it implies social innovation, also includes a number of processes that encompass co-creation:

1. Granting access (e.g. to an infrastructure); 2. Participation (an example in DARIAH could be Working Groups as communities of practice, a space of exchange for all kinds of initiatives); 3. Use, which has an impact on public policies; 4. Reflection, which describes a process that relies on individuals who reflectively appropriate culture and become producers of new knowledge. Reflection implies the notion of thinking about diversity. In research policy it has been used for example in Horizon 2020 societal challenge calls for 'Inclusive, Innovative and Reflective Societies'. 5. Inclusion, which means granting access to the social process of sharing one's own reflection in participatory co-creation processes. On a societal level, the places where co-creation takes place are spaces of exchange, such as libraries, museums, science centres, research infrastructures. In this context, citizens engage in the process of sharing experiences while appropriating common goods content.


domain: spi phys math chim

text:
M Balesdent

L Brevault

B Paluch

R Wuilbercq

N Subra

R Thépot

A Patureau De Mirand

Design and optimization of glide-back reusable launch vehicle architectures

In the context of the design of partially reusable launch vehicles, different alternatives may be investigated to recover the first stage while minimizing the costs of reusability and maximizing the performance and reliability. In this paper, a winged configuration of reusable first stage, called glide-back, is studied. This architecture uses the main propulsion system of the first stage to perform a boost-back burn and return to the landing site by a gliding mode using additional lifting surfaces. A focus is made on the design of a reusability kit that can be added to a classical stage to provide it with reusability capabilities. The tradeoff between the design of the reusability kit and its impact on the ascent phase, staging point and global performance of the vehicle is investigated through aerodynamics and trajectory analyses.

Introduction

In the context of the design and use of partially reusable launch vehicles, different design alternatives may be investigated to recover the first stage while minimizing the costs of reusability and maximizing the vehicle performance and reliability. [START_REF] Vila | Weighting options for the next generation of ariane launchers IAC-17-D2. 4.2[END_REF] The toss-back configuration has proven its operational feasibility. Alternative configurations, such as glide-back or fly-back concepts, are worth while to be studied in order to assess the trade-off between different technologies. In this paper, a glide-back configuration is investigated for the first stage. It combines both space and aeronautical technologies to recover the vehicle first stage. The proposed architecture takes-off vertically and lands horizontally. After the lift-off and the first stage ascent mission, the second stage is jettisoned and the first stage reignites a part of its rocket engines to cancel its horizontal velocity. Then, the vehicle performs an aerodynamical reentry and glides back to the landing site. For that purpose, aerodynamical nose, lifting surfaces, gears and corresponding power avionics are added to the initial stage configuration. The overarching aim of this work is to study a "reusability-kit" in order to provide the first stage with both expendable and reusable capabilities. In the context of reusability, the stage can be used several times in reusable mode, and in expendable mode during its final flight. Before lift-off, the kit is mounted on a central core. [START_REF] Brevault | Surrogate model-based multiobjective mdo approach for partially reusable launch vehicle design[END_REF] At the end of the flight, either the kit and the central core are refurbished for the next flight in reusable mode or the kit is removed and installed on another central core if the current core is used for expendable mission. In that way, the reusability kit may be used numerous times as means to lower the costs of access to space.

This study is part of a joint project between the French Space Agency (Centre National d'Etudes Spatiales -CNES) and the French Aerospace Lab (Office National d'Etudes et de Recherches Aérospatiales -ONERA) on Reusable Launch Vehicle (RLV) that started in 2018 and will last until 2020. The goal of this study is to provide a first design for the RLV taking into account the kit integration constraints, the use of LOx/LCH4 PROMETHEUS rocket engine technologies and the specificities of Kourou spaceport operations for winged launch vehicles. In order to estimate the performances of such vehicles, adapted modeling tools and simulations are required through a multidisciplinary approach. In this work, a focus is made on the multidisciplinary process developed in order to assess the performances of the RLV. The results presented in this paper are preliminary results of the conceptual phase for such a winged RLV.

The paper is organized as follows. In Section 2, the design specifications and constraints are presented. In Section 3, the modeling tools and the multidisciplinary process developed for the performance assessments of such a type of vehicles are described. Then, in Section 4, preliminary results are presented. A focus is made on aerodynamics sensitivities to wing geometry and airfoil. Moreover, trajectory analyses are provided with sensitivities to key parameters during the Return To Landing Site (RTLS) phase. Finally, in Section 5, the perspectives of the project are detailed, especially the on-going works.

Design specifications and constraints

The present study focuses on Two-Stage-To-Orbit with a reusable first stage. It consists in modifying a conventional first stage into a winged RLV. The Ariane-Next configuration is used as a baseline (Figure 1). The mission specifications that have been chosen to perform the design of the glide-back reusability-kit are described in this Section. The goal is to insert a payload of 6.0 metric tons into a 800km circular SSO orbit (Table 1). The vehicle for the reusable mission is a Vertical Take Off -Horizontal Landing configuration. It first lifts off from Kourou carrying out the ascent mission and then returns near to the launch site. Concerning the launch vehicle architecture, the first stage is propelled with 7 PROMETHEUS engines using LOx/LCH4 propellant. The second stage is also propelled with another PROMETHEUS engine. An expendable baseline and an example of a glide-back configuration are illustrated in Figure 1. The reusability kit is composed of the following components (Figure 2):

• additional lifting surfaces including wings and canards,

• front and rear gears,

• interstage including canards'attachment, front gear integration and required avionics for the first stage,

• vertical stabilizer,

• aerodynamic nose.

The main wings and rear landing gears are located in a reusability pack located in a case that is attached to the main core at the thrust frame (Figure 2). This kit can be removed for the expendable mission. The front landing gear, nose and canards are attached to a skirt located in front of the first stage.

In addition to these specifications, operational constraints on the vehicles are considered. The loads (axial and transverse loads, dynamic pressure and aerothermal flux) during the flights must not exceed a threshold during both the ascent and the return phases. Moreover, safety and visibility constraints near the launch and landing sites are taken into account to ensure the RLV operation safety.

Models and design process

In this Section, all the disciplines that are used in the design process are briefly described.

Propulsion

The two stages are propelled by PROMETHEUS engines using LOx/LCH4 propellant. [START_REF] Iannetti | PROMETHEUS, a low cost LOx/CH4 engine prototype[END_REF] The first stage uses 7 engines and the second stage uses only one engine. The engines are throttable and re-ignitable. The throttling of the engines is exploited for both ascent and return phases in order to respect the maximal axial load constraints. The characteristics and performance of the PROMETHEUS engine are provided by CNES. The thrust varies from 300kN to 1000kN for each engine. [START_REF] Iannetti | PROMETHEUS, a low cost LOx/CH4 engine prototype[END_REF] The throttling level is optimized during the MDO (Multidisciplinary Design Optimization) process.

Geometry and sizing

The geometry and sizing discipline allows to model the launch vehicle to provide consistent outputs for the estimation of the aerodynamics (meshes) and the mass budget of the vehicle. This module consists of tools chained together from geometrical modeler to a parametric definition of the vehicle up to the mesh generation for the aerodynamic coefficient estimation. From the main decision variables (length of tanks, planform description of the wing surfaces, etc.), the geometry module allows to build a consistent CAD parametric design integrated in the MDO framework. This module gives as outputs meshes for the aerodynamics discipline CFD (Computational Fluid Dynamics) calculations and consistent lengths and scales for mass budget estimation (Figure 3). Concerning the mass budget estimation, the masses of the different elements of the stages are predicted using in-house tools developed at ONERA. For the primary structures of the first stage (e.g. skirts, tanks, wings), analytical formula and local FEA (Finite Element Analysis) are used to take into account specific aspects such as the distribution of bending moments, buckling, etc.. An important matter is to take into account the transversal loads that occurs during the re-entry. These loads are specific to such configurations and have an impact on the design of the overall stage. MER (Mass Estimation Relationships) are mainly used for the secondary structures (e.g. gears, equipments, etc.). The second stage is designed using standard expendable MER as such a stage is more conventional. This module is integrated as a part of the MDO process to update the mass of the different parts of the stages depending on the loads endured in the flight phases and calculated by the trajectory analysis. The entire chain of geometry and sizing is wrapped into OpenMDAO 6 as a component in order to have the possibility to define some sizing variables as design variables to offer a control by an optimization process.

Aerodynamics

Estimating with accuracy the aerodynamics behavior of such vehicles is challenging. Indeed, the Mach number and angle of attack vary greatly during the different flight phases occuring during the mission (ascent and re-entry, subsonic, supersonic, hypersonic, propelled phases or not). This requires to use dedicated tools for the aerodynamics coefficient estimation. For that purpose, different tools of various fidelity levels (three in total) have been used. The first level of fidelity consists of two internal low fidelity models (one based on semi-empirical formulations named MISSILE [START_REF] Denis | ONERA's aerodynamic prediction code -MISSILE[END_REF] and one based on Local Surface Inclination methods named SHAMAN) that have been implemented to obtain quick estimates of the aerodynamic coefficients. To improve the accuracy of the predictions, specifically for the glide-back flight phase, a second level of fidelity with Euler CFD calculations has been used with an aerodynamic estimation chain based on a derivation on the ONERA's code CANOE 3 relying on SU2. [START_REF] Palacios | Stanford university unstructured (su2): Analysis and design technology for turbulent flows[END_REF] Finally, for the highest level of fidelity, several RANS CFD calculations (Figure 4) have been performed on specific aerodynamics configuration in order to validate the model and to adjust the aerodynamic coefficient estimates. To aggregate the different levels of fidelity, a surrogate model of the previously described models is built via co-kriging techniques. [START_REF] Alexander Ij Forrester | Multi-fidelity optimization via surrogate modelling[END_REF][START_REF] Le | Recursive co-kriging model for design of computer experiments with multiple levels of fidelity[END_REF] This technique uses Gaussian Processes to combine different fidelity models based on the correlation between the model responses. The idea is to build the surrogate model on the higher fidelity model (expensive to evaluate) and enrich it using lower fidelity model (cheaper to evaluate) responses. The outputs of this discipline constitute the aerodynamic models of drag and lift coefficients as functions of the Mach number and the angle of attack. These models have been validated and are used in the trajectory analysis and optimization that follows.

Trajectory

The trajectory discipline aims at finding the optimal guidance law (orientation and thrust level of the engines) to reach the target orbit while satisfying all of the constraints. A three-dimensional rotating Earth frame model is used for the trajectory integration. The ascent trajectory is analog to expendable launch vehicles and is composed of the following phases: first a vertical lift-off, followed by a pitch over maneuver and a gravity turn during the atmospheric flight. Once the exo-atmospheric conditions are reached, the vehicle performs a controlled ascent phase (for both the first and the second stages). Then, a coasting phase (ballistic flight) is considered for the second stage. Finally, a circularization burn is performed at the apogee of the transfer orbit to reach the target orbit, exploiting the re-ignition capability of the PROMETHEUS engine. During the ascent, the pitch angle and yaw angle are optimized using different kinds of control laws depending on the flight phase (pitch over maneuver, controlled phase, etc.). The objective is to reach the SSO orbit and minimize the propellant consumption while satisfying the constraints corresponding to the maximal axial and transverse load factors, the maximal dynamic pressure, the maximal angle-of-attack, and the visibility and safety aspects. In order not to exceed the maximal axial load factor, the throttling of the engines is also optimized both for the first and the second stages. The ascent phase and RTLS (Return To Landing Site) strategy for the glide-back mission are illustrated in Figure 5. • turn around phase: this phase allows to place the stage in an appropriate orientation for the boost-back burn ;

• boost-back maneuver: in this phase, the rocket engines are re-ignited to invert the velocity vector and provide an impulse to the landing site. For this phase, the decision variables are the orientation of the stage (pitch angle and azimuth) as well as the throttling of the engines (only 3 engines are used for this maneuver) ;

• atmospheric re-entry: this phase follows the boost-back maneuver and performs a controlled re-entry to limit the loads ;

• aerodynamical ressource and glide phases: after re-entry, the first stage performs a pull up maneuver and a glide phase to exploit the lifting surfaces to reach the landing site, maximizing the lift-to-drag ratio. The decision variables of this phase are the angle of attack profile and the bank angle profile ;

• final phase: this phase is composed of a turn to align with the runway while satisfying the visibility and safety constraints. The decision variables are analog to the gliding phase.

Figure 6 details the different maneuvers of the RTLS phase. The objective of the optimization process for this phase is to minimize the propellant consumption while satisfying the constraints on the maximal axial and transverse load factors, maximal dynamic pressure and thermal flux during re-entry, maximal angle-of-attack during the glide phase, the maximal velocity at landing, and visibility and safety aspects.

Design process

All the disciplines have been integrated into an MDO design process using the openMDAO framework developed by NASA and the university of Michigan. [START_REF] Gray | OpenM-DAO: An Open-Source Framework for Multidisciplinary Design, Analysis, and Optimization[END_REF] To ease the integration process, the WhatsOpt environment developed at ONERA is used. [START_REF] Lafage | Whatsopt: a web application for multidisciplinary design analysis and optimization[END_REF] The decision variables are the variables defining the kit (e.g., planforms and profiles of wings and canards), propellant masses of the first stage for both ascent and return phases and propellant masses of the first and

Preliminary analyses

The key drivers for the reusability kit design that are investigated in this paper are the planform and airfoil profile of the wings 4.1), sensitivity to key control parameters of the return trajectory envelop (Section 4.2). More precisely, the return mission is realized by combining a boost-back burn using additional propellant mass and aerodynamics surface for the gliding phase. As the figure of merit for this study is the Gross Lift Off Weight (GLOW), this results in a trade-off between additional propellant mass and structural mass of lifting surfaces of the kit. Moreover, these two components have an important impact not only on the return phase but also on the ascent phase (additional dry mass and drag at ascent).

DESIGN AND OPTIMIZATION OF GLIDE-BACK REUSABLE LAUNCH VEHICLE ARCHITECTURES

Sensitivity analyses about wing design

In order to estimate the influence of the wing planform and airfoil, a sensitivity study has been performed for two wing profiles: double wedge and symmetrical NACA (Figure 8). The first tends to present advantages for the supersonic regime whereas the latter is more efficient for the subsonic regime. For this analysis, two aerodynamic databases have been generated (Figure 9) and Lift-over-Drag (L/D) ratio of the configurations have been compared. Aerodynamic results show a benefit to use NACA airfoil profile due to a better L/D ratio especially in the subsonic regime that is of prime interest concerning the return gliding trajectory (Figure 10). However, the configuration with NACA airfoil profile presents a larger drag in supersonic regime due to the radius of curvature, that can be disadvantageous for the ascent phase inducing more propellant for this phase. Then a global trade-off between the performance for both ascent and return phases has to be performed. The difference in terms of pressure field along the airfoils is illustrated in Figure 9. A coupled analysis between aerodynamics and trajectory optimization is required to assess this trade-off (see next Section). Concerning the wing planform, two different wingspans, corresponding to 3 and 5 times the main core diameter have been studied (the wing share the same root chord, that is set with respect to the thrust frame length). As expected, the L/D ratio for the larger wing presents better characteristics. However, it comes to the cost of increasing the size of the reusability kit and additional space needed on the launch pad for the ground operations and lift-off.

Ascent and return trajectory profiles

In this Section, results of trajectory optimization are summarized. In these simulations, the NACA airfoil profile is considered (see Section 4.1, with the wingspan equivalent to 5 times the main core diameter). In Figure 11, the altitude profile as a function of time is described, showing the propelled phases for the first and second stages along with the coasting phase allowing to reach the target orbit altitude where a circularization burn is performed. The staging altitude is about 50km and the altitude at the second stage engine cut-off is around 160km. The ascent trajectory for the first stage is mainly driven by the visibility and safety constraints (Figure 12). Due to the load constraints during the ascent, the trajectory of the first stage is performed with a very low angle of attack during the atmospheric phase to keep the transverse loads under the maximal load allowed. The relative low staging velocity is due to the need to bring back the first stage. Indeed, additional propellant mass for the return phase has to be carried out during the ascent phase. This induces a large virtual additional dry mass for the ascent phase that impacts the staging point.

The trajectory of the return phase is illustrated in Figure 13. It may be decomposed into three main phases: the turn around phase, the boost-back phase, and the re-entry and gliding phases as depicted in Figure 13a. After staging around 50km of altitude, the turn around phase enables to separate with the second stage and orientate the first stage in order to perform the boost-back burn. Then around 60km of altitude, 3 PROMETHEUS engines are re-ignited, allowing to cancel the horizontal component of the velocity (Figure 13b) and give an impulse toward the landing site. After the engines' cut-off, a ballistic phase with first a parabolic flight with a peak altitude of 100km. Then a re-entry phase is performed at a low angle-of-attack, followed by an aerodynamic pull-up maneuver ending with a gliding phase (starting at a distance of 60km to the landing site and an altitude of around 15km) up to the landing site. At the end of this phase, a final turn is performed using aerodynamic forces to be aligned with the runway (Figure 13c). A sensitivity analysis of the trajectory to the radius of the terminal turn has been performed and is illustrated in Figure 15, while satisfying the safety constraints for the return and landing phases. With regard to the boost-back phase, two steps may be distinguished, the first one allows to cancel the horizontal component of the velocity (inversion of the velocity vector), the second one enables to orientate the stage toward the landing site. As it can be seen in Figure 13a, the most important part of the boost-back burn is the inversion of the velocity vector. The propellant mass resulting for the impulse to the landing site is very low (Figure 14). This is to be the expected advantage of the glide-back configuration as it uses mainly the lifting surface to perform the return to the landing site mission. Finally, a sensitivity analysis about the aerodynamic choices on the entire trajectory has been performed. Figure 16 illustrates the impact of the selection of airfoil profiles (NACA vs. double-wedge) on the RTLS phase. As described in Section 4.1 the L/D ratio of the first stage with NACA airfoil profile is larger than with the double wedge profile in the subsonic regime. This impacts the gliding capabilities of the vehicle and therefore the distance where the aerodynamic pull-up maneuver is carried out). This pull-up maneuver is mainly driven by the satisfaction of the maximal transverse load constraints.

Conclusion and future works

This paper presents an on-going effort to study the design of a glide-back architecture for the reusability of the first stage. The study is focused on the design of a reusability kit that can be added to the core of a first stage to provide it with reusability capabilities. Preliminary aerodynamic analyses and global trajectory optimizations (ascent and return)

Figure 2 :

 2 Figure 2: Glide-back configuration with the components of the reusability kit (in black)

Figure 3 :

 3 Figure 3: Illustration of geometry discipline

Figure 4 :

 4 Figure 4: Illustration of CFD RANS calculations: full configuration in supersonic flight (left) and first stage configuration in subsonic glide (right)

Figure 5 :

 5 Figure 5: Ascent phase and RTLS by glide-back strategy

Figure 6 :

 6 Figure 6: Illustration on the different maneuvers during the RTLS phase

Figure 7 :

 7 Figure 7: Illustration of the MDO process for the glide-back architecture in the WhatsOpt environment

Figure 8 :

 8 Figure 8: Illustration of double wedge (left) and NACA (right) airfoil profiles for the main wings

Figure 9 :

 9 Figure 9: Pressure fields (CFD Euler calculations) for two studied configurations (up: symmetrical NACA, bottom: double-wedge) at subsonic regime (Mach number: 0.5, angle of attack: 5 deg)

  DESIGN AND OPTIMIZATION OF GLIDE-BACK REUSABLE LAUNCH VEHICLE ARCHITECTURES

Figure 10 :

 10 Figure 10: Lift over Drag ratio between NACA (dash line) and double-wedge (solid line) airfoil profiles, as a function of Mach number and angle of attack. Two configurations are evaluated: wingspan equivalent to three times the stage diameter (left), wingspan equivalent to five times the stage diameter (right).

  Illustration of the ascent trajectory, altitude as a function of time (b) Illustration of the ascent trajectory for SSO orbit

Figure 11 :

 11 Figure 11: Illustration of the ascent trajectory with the propelled and coasting phases

Figure 12 :

 12 Figure 12: Illustration of altitude, velocity and flight path angle as a function of time for the ascent propelled phase

Figure 13 :

 13 Figure 13: Illustration of generic return trajectory: altitude as a function of distance to the landing site, relative velocity as a function of time, and latitude as a function of longitude

Figure 15 :

 15 Figure 15: Illustration of the sensitivity study to the radius of the terminal turn (yellow: 3km, green: 5km, red: 7.5km, blue: 10km)

Figure 16 :

 16 Figure 16: Illustration of return trajectories for the two airfoil profiles described in Section 4.1, altitude as a function of the distance to landing site (in solid line: NACA airfoil profile, in dash line: double-wedge airfoil profile)

Table 1 :

 1 Summary of mission specifications

	Target orbit	SSO, 800km
	Launch site	CSG, Kourou, French Guiana
	Landing site	CSG, Kourou, French Guiana
	Payload mass 6 metric tons
	Vehicle type	Two-Stage-To-Orbit (TSTO) reusable vehicle

DOI: 10.13009/EUCASS2019-604

DESIGN AND OPTIMIZATION OF GLIDE-BACK REUSABLE LAUNCH VEHICLE ARCHITECTURES

involving different configurations of lifting surfaces have been performed in order to assess the trade-off between the size of lifting surfaces, the required additional propellant mass for the return mission and their impact on the ascent phase and global performance of the launch vehicle. Other concepts will be studied in the future, especially a fly-back configuration using additional air-breathing propulsion to perform the RTLS mission.

Acknowledgments

The work is funded by the joint project "Programme d'Intérêt Commun -Lanceurs Réutilisables" between CNES and ONERA and by the HERACLES project (Hypersonic Efficient and Reusable Aerospace Concepts for Launcher Evolution Strategies) funded by ONERA.