space flight

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

• noun Flight beyond the atmosphere of Earth.

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

• noun the process or event in which vehicles travel into outer space.

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

• noun uncountable Flight into, from or through space.
• noun countable A voyage in space.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a voyage outside the Earth's atmosphere