In this work, we present a new software package for interplanetary navigation of spacecraft called Scarabaeus (SCB). Inspired by the successful development and use of the Basilisk tool by our colleagues at the University of Colorado, we seek to develop a similar open-source navigation tool for the benefit of any future interplanetary mission. Scarabaeus’ architecture is based on a modular, object-oriented, Python front-end with a Rust back-end for computationally intensive components.
SCB is being developed for direct applicability for the Emirates Mission to Explore the Asteroid Belt (EMA). EMA is being developed under the lead of the United Arab Emirates Space Agency, which in 2028 will send a spacecraft, the MBR Explorer, to explore the asteroid belt. The spacecraft will fly by six main belt asteroids and rendezvous with a 7th asteroid, 269 Justitia. Each of the flybys targets an asteroid that has not yet been explored and is expected to fill in gaps in the understanding of the asteroid belt. Once in orbit around Justitia, the spacecraft will conduct a months-long remote sensing campaign to characterize this unexplored object’s composition and origins. This will include a gravity science study conducted using ground-based navigation techniques as well as employing the suite of scientific payload carried by the MBR spacecraft. SCB is developed to support all phases of this mission, including processing radiometric tracking and optical navigation measurements.
SCB applicability, however, extends beyond this use case, making it flexible and modular enough to other missions and for research purposes. Its open-source nature and its modularity are also specifically designed to encourage future contributions from interested developers. The initial results of using Scarabaeus demonstrate its usage for interplanetary cruises with maneuvers, planetary and small body flyby with impulsive trajectory correction estimation and measurement processing capabilities using radiometric data from previously flown missions.
This paper presents Scarabaeus’ design philosophy, architecture, and main capabilities along with preliminary analyses, validations, and showcasing real measurement processing capabilities from previously flown missions. These demonstrate the tool’s potential for contributing to the advancement of precise navigation technologies for deep space applications  

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.