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The European Astronautical Space Transportation (EURASTROS) study [1], which was carried out in 2021, was a joint undertaking of the German Aerospace Center (DLR) and ArianeGroup GmbH with the main objective to identify missing technologies and infrastructures for an independent European space transportation of astronauts to Low Earth Orbit (LEO) and to predict the corresponding cost. The study included several trade-offs regarding e.g. ascent, descent and abort trajectories, space system design and launch abort system concepts. The selected reference launch vehicle is Ariane 6.4., to be launched from a future crew-rated Guiana Space Center in Kourou, French Guiana. The Apollo-shaped crew capsule is served by an ASTRIS kick-stage derived service module, and the proposed launch abort system is a tower-like concept which was considered favorable in terms of technical maturity and cost. Details are presented in [1] and only briefly summarized within this work. The present paper focusses on the cost estimation of the overall system including all segments, i.e. space, launch and ground. The estimation is based on a dedicated DLR cost model, using amongst others technical inputs from ArianeGroup and DLR. The paper furthermore outlines the development approach, primarily for the space segment, which is a major input for the cost estimate. Four test and demonstration flights are proposed to eventually provide a certified system for an independent European crew access to LEO. Depending on their objectives, the space and launch segments are constituted of different development, qualification and flight models, which is detailed within the work presented. The model philosophy is captured within the cost estimate by using linear cost factors on the first theoretical flight unit (TFU or T1) following the T1-equivalent approach on subsystem level as described in [2]. All major cost estimation methodologies have been applied to identify the recurring (RC) and non-recurring cost (NRC), i.e. parametric, engineering build-up and analogy-based estimation. All cost figures within this paper are normalized to fiscal year 2021 constant euros. Based on the assumptions made, the point estimate of the total NRC, including a first crewed flight to the International Space Station, is around 4100 M and the RC per mission in the 400 M range, considering a conservative unit theory learning curve with a slope of 90% and assuming 20 missions within 10 years, as an example. The biggest contributor identified for the development cost is the space segment with almost two third of the NRC. A comparison with other international programs, as analyzed amongst others in [3], and previous studies, indicates the similarity to current commercial programs and hence also a viable case for such a European endeavor. It has to be noted that so far during the study, re-usability aspects for the space and launch segment were not particularly considered for the technical and cost analyses. The paper concludes with the discussions of cost drivers, sensitivity analyses as well as business options and recommendations which have been conducted and derived throughout the EURASTROS study. [1] A. Gulhan, M. Wolf, et al., Final Presentation of the Study on European Astronautical Space Transportation (EURASTROS), 15.11.2021 [2] G. Reinbold, Successful Cost Estimation with T1 Equivalents, Proceedings of 2016 International Training Symposium, Bristol, UK, October 2016 [3] E. Zapata, An Assessment of Cost Improvements in the NASA COTS/CRS Program and Implications for Future NASA Missions, AIAA, 2017 |
