This glass dome is where the toilet is, crew member Jared Isaacman, who purchased the four seats for the mission, told Insider’s Morgan McFall-Johnsen in July.

SpaceX CEO Musk tweeted on Thursday that he had spoken with Isaacman, Hayley Arceneaux, Sian Proctor, and Chris Sembroski, the four people on board.

“All is well,” Musk said in his Twitter post. He didn’t mention what was discussed.