MOSAiC has been years in the planning. But do the scientists involved expect it to go to plan? I asked participants of Leg 1 of the expedition, and their words serve as fascinating context for the changes since then. At the end I give an update on how plans have been remade due to Coronavirus. You can keep up to date with the MOSAiC expedition on this live web app: https://follow.mosaic-expedition.org/ and find stories from across the media on the MOSAiC website: https://mosaic-expedition.org/.