Astronauts need to add space headache to their list of occupational hazards, say researchers. After quizzing 17 seasoned astronauts they found more than two-thirds suffered from headaches on missions yet were headache free back on earth. The disabling headaches appeared unique - described by the crew as "exploding" - and were generally unrelated to common space motion sickness. The Dutch investigators work is published in the journal Cephalalgia.