Abstract This work presents some of the first results from a recently developed fusion propulsion code which calculates the performance of an advanced spacecraft design. HeliosX is a system integrated programming design tool written in Fortran 95 for the purpose of calculating spacecraft mission profile and propulsion performance for inertial confinement fusion driven designs. This code uses the vehicle configuration input and then calculates the likely mission profile for a given destination target. The key capability under development is the inclusion of the fusion propulsion system and an adequate modelling of its likely energy outputs and how this integrates into the mission profile. The results of a comparison to a concept from the literature are firstly presented for an interstellar flyby probe and then perturbations of this design to include updates and revisions to its input parameters and expected performance. Although the code is still being developed the early results show good potential to enabling a numerical tool for conducting spacecraft performance assessment of fusion based propulsion systems. The preliminary results of modelling different missions are shown for an interstellar target in $\sim$37–100 years trip times and $\sim$0.05–0.12c cruise speeds in flyby and rendezvous modes for orbital insertion to a distance $\sim$4.3–5.9 $ly$. A description is given for how the baseline concepts are being evolved since the code has been developed in parallel with the design process which aims to design improved vehicle concepts. Ultimately the calculations shown in this paper are working towards the development of a design tool which can facilitate the proper analysis of a range of different spacecraft designs and place them on a consistent modelling basis so that feasibility assessments can be made.

Highlights • First presentation of design tool that permits rigorous assessment of assumptions used in space propulsion calculations driven by an ICF propulsion engine. • Describes how the ICF capsule assumptions and performance outputs influences the integrated spacecraft design, systems and associated mission profile. • The code has been applied to a historical design as a form of numerical validation of its physics and engineering algorithms to include modern updates. • Perturbations of the design have been made as more engineering elements and algorithms have been added to the code to increase its design applicability. • A review has been conducted of the historical design to inform the generation of advanced baseline models and apply to a wider design suite.