The Emirates Mission to the Asteroid Belt (EMA) will launch the Mohammed Bin Rashid Explorer (MBR Explorer) in 2028 to conduct six asteroid flybys and three gravity assist encounters while operating primarily under solar electric propulsion (SEP). To support this complex low-thrust mission, a comprehensive open-source navigation software suite named Scarabaeus (McMahon et al., 2025),capable of performing operational orbit determination (OD), is being developed to provide OD and operational trajectory products.

To ensure consistent operational products and the use of the most up-to-date estimated parameters, the maneuver planning tools for EMA have been built as a wrapper around the dynamics modelling and numerical trajectory propagation in Scarabaeus. This integration allows the maneuver-design pipeline to inherit the exact initial state vector (position, velocity, mass), and the latest estimated force models for accurate trajectory propagation. This setup eliminates the need for extensive cross-validation between multiple tools by simply inheriting dynamics from the OD solution when planning maneuvers.

Finite burn targeting capability is being developed within Scarabaeus to support maneuver design throughout the EMA mission. The system is designed to target key interplanetary waypoints, B-plane parameters for flybys and gravity assists, and orbital parameters during proximity operations.

To modify the finite burn parameters, the framework employs a derivative-based numerical optimisation approach tied to the trajectory propagation capabilities in Scarabaeus. The optimisation framework employs a forward shooting method, eliminating any match point discontinuities. While this is more desirable for operational use, it does introduce strong numerical sensitivities and derivative scaling issues, particularly on long propagation arcs. Therefore, this methodology requires relatively accurate initial guesses for burn durations and directions, and will require piecewise targeting for long duration targeting problems.

The core targeting algorithm uses Interior Point Optimizer (IPOPT) (Wächter & Biegler, n.d.), a robust Sequential Quadratic Programming-based solver, to determine the optimal control parameters required to achieve the desired trajectory while meeting the mission constraints. The optimiser can adjust the maneuver start and end time, as well as the steering variables.

Partial derivative information is accumulated through chaining of State Transition Matrices as well as the control sensitivity matrices- generated by integrating the dynamics equations concurrently with the trajectory. These partial derivatives are chained with decision variable transcription and constraint formulations and then provided to the gradient-based IPOPT solver.

This paper will provide an overview of the Scarabaeus operational targeting framework that couples navigation derived dynamics with maneuver planning capabilities to ensure full consistency across mission operations. Results will show the verification of the finite burn models through comparisons to other mission design tools as well as example targeting problems and studies of initial guess sensitivity.
 
ACKNOWLEDGMENTS

Funding for the development of this work is provided by the United Arab Emirates Space Agency to its knowledge partner, the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics as part of the Emirates Mission to Explore the Asteroid Belt.
 
 
REFERENCES

McMahon, J., Pugliatti, M., G. Fereoli, S. Pattamudu-Manoharan, Z. Ellis, A. Cabra, M. Almashjari, M. Kuleib, W. Frank, & J. Knittel. (2025). THE SCARABAEUS OPEN-SOURCE NAVIGATION TOOL: PRELIMINARY RESULTS AND REAL MEASUREMENTS. Colorado Center for Astrodynamics Research, University of Colorado, United States.
 
Wächter, A., & Biegler, L. T. (n.d.). Ipopt documentation. COIN-OR Foundation. https://coin-or.github.io/Ipopt/