The Kessler Run: On the Design of the GTOC9 Challenge

As organizers of the 9th edition of the Global Trajectory Optimization  Competition we were tasked to design a challenging trajectory optimization problem to be solved during the duration of one month. We gave ourselves the goal to create a problem which was accessible enough for newcomers, deep enough for experts, unconventional in its objective function and which allowed for a real-time format of the competition. This document describes our design process from the initial idea up to the final form. We document some of our experiments conducted to learn about the solution landscape of an earlier simplified version of the problem and show how this exploration helped us in tuning the problem parameters to create a balanced and challenging task.