Apollo8 was launched at 12:51:00 UTC (07:51:00 Eastern Standard Time) on December 21, 1968. On the second day Borman awoke feeling ill. He vomited twice and had a bout of diarrhea; this left the spacecraft full of small globules of vomit and feces, which the crew cleaned up as best they could. Borman did not want anyone to know about his medical problems, but Lovell and Anders wanted to inform Mission Control. The Apollo8 crew and Mission Control medical personnel concluded that there was little to worry about and that Borman's illness was either a 24-hour flu, as Borman thought, or an adverse reaction to a 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 Mercury and Gemini missions because those astronauts could not 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.