Synthetic Long-Period Comet and Interstellar Object Populations for Comet Interceptor Target Screening

The European Space Agency’s (ESA’s) Comet Interceptor (CI) mission’s goal is to encounter a yet undiscovered long period comet or an interstellar object. Mission’s core target selection screening depends on orbital geometry, perihelion distance, the position of the ecliptic node, and the timing of the encounter. Because the final target is unknown before launch, it is important to understand how different target populations affect early mission planning.

This preliminary study develops a population-based workflow for generating and screening synthetic long period comet and interstellar object candidates for Comet Interceptor target analysis. Publicly available orbital elements of known long period and hyperbolic objects are used to construct candidate distributions. These are compared with simplified synthetic population assumptions to test how different models influence the number and geometry of possible targets. The generated trajectories are then filtered using mission relevant criteria, such as perihelion distance, ecliptic node geometry, and approximate timing relative to a possible interceptor departure.

Selected candidate orbits are converted into Cartesian state vectors, propagated using the DOCKS propagator, and exported as SPICE compatible SPK kernels for geometry inspection and reproducibility. This is designed to compare how different long period comet and interstellar object population assumptions influence the number, spatial distribution, and geometry of candidate targets. This work can provide a basis for later studies on population modelling and uncertainty aware target assessment for CI as well as future small body missions.