  Proper modelling of the gravitational fields of irregularly shaped asteroids
and comets is an essential yet challenging part of any spacecraft visit and
flyby to these bodies. Accurate density representations provide crucial
information for proximity missions which rely heavily on it to design safe and
efficient trajectories. This work explores using a spacecraft swarm to maximise
the measured gravitational signal in a hypothetical mission around the comet
67P/Churyumov-Gerasimenko. Spacecraft trajectories are simultaneously
propagated with an evolutionary optimisation approach to maximise overall
signal return. The propagation is based on an open-source polyhedral gravity
model using a detailed mesh of 67P and considers the comet's sidereal rotation.
We compare performance on a mission scenario using one and four spacecraft. The
results show that the swarm achieved almost twice the single spacecraft
coverage over a fixed mission duration. However, optimising for a single
spacecraft results in a more effective trajectory. Overall, this work serves as
a testbed for efficiently designing a set of trajectories in this complex
gravitational environment balancing measured signals and risks in a swarm
scenario.
  The codebase and results are publicly available at
https://github.com/rasmusmarak/TOSS
