On 20 September 2019, the German research icebreaker Polarstern set out on the MOSAiC expedition. The plan was to let the ship freeze into the Arctic ice and drift with it for a year. The federal government described the departure in one sentence: Nach zehn Jahren der Vorbereitung war es soweit, after ten years of preparation, the time had come. The expedition cost 140 million euros. About 600 scientists from different fields took part. Six icebreakers were to supply the ship, and a runway for supply aircraft was to be built on the ice floe. On 4 October 2019, the ship was frozen into a floe and its main engines were switched off. From then on, it moved only with the ice, inside a drift corridor that had been calculated in advance.