The latest mission to the innermost planet in the solar system hit a milestone last week. After an eight year journey, BepiColombo finally separated from its propulsion stage to set itself up for an orbital insertion to Mercury. Taking place on September 3rd, the separation, which is part of a much longer series of logistical steps over the next few months, seemed to go without a hitch. But getting to that point was certainly a process, and still more challenges lie ahead.