 The Apollo 8 crew and Mission Control medical personnel held a conference using an unoccupied second @-@ floor control room ( there were two identical control rooms in Houston , on the second and third floors , only one of which was used during a mission ) . The conference participants concluded that there was little to worry about and that Borman 's illness was either a 24 @-@ hour flu , as Borman thought , or a reaction to the sleeping pill . Researchers now believe that he was suffering from space @-@ adaptation syndrome , which affects about a third of astronauts during their first day in space as their vestibular system adapts to weightlessness . Space @-@ adaptation syndrome had not occurred on previous spacecraft ( Mercury and Gemini ) , because those astronauts couldn 't move freely in the small cabins of those spacecraft . The increased cabin space in the Apollo Command Module afforded astronauts greater freedom of movement , contributing to symptoms of space sickness for Borman and , later , astronaut Russell Schweickart during Apollo 9 . 
