space sickness

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Motion sickness caused by sustained weightlessness during space flight, usually accompanied by disturbance of the inner ear.

from the GNU version of the Collaborative International Dictionary of English.

• noun a group of symptoms, prominently nausea, but sometimes including lethargy, headache, and sweating, occuring under the weightless conditions of space flight.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun motion sickness caused by the weightlessness of space flight