When is a crash landing not a crash landing?

More than 12 years after it launched and after 786 days in orbit around comet 67P, the European Space Agency's will make its final maneuver this morning: a slow, but undeniably terminal, descent onto the comet's dusty surface. Even at such a leisurely pace, many people would call this a crash landing, but for reasons that will become clear, this is a term that many people involved in the mission seem to avoid.