We study the practical implementation of zero-order-hold (ZOH) transcriptions for spacecraft trajectory optimisation, identifying a set of design principles that render them robust across a broad class of dynamical settings without problem-specific tuning. The contributions are fourfold: (i) a thorough study of the forward--backward shooting construction, denoted ZOHα; (ii) a redundant four-dimensional throttle parameterization that eliminates the singularity of the control influence matrix along ballistic arcs; (iii) a softmax time-grid encoding that avoids ordering constraints on segment durations while preserving full differentiability; and (iv) the TOPS benchmark (Trajectory Optimisation Problems in Space), a suite of 28 problems spanning four dynamical models, two-body Cartesian, modified equinoctial elements, circular restricted three-body, and solar sailing, designed to be extended over time.
Cite
@article{arxiv.2605.11043,
title = {A practical guide to implementing zero-order-hold interplanetary trajectory legs},
author = {Dario Izzo and Harry Holt and Giacomo Acciarini and Laurent Beauregard and Yuri Shimane},
journal= {arXiv preprint arXiv:2605.11043},
year = {2026}
}
Comments
Work presented at the 30th International Symposium on Space Flight Dynamics (ISSFD)