(n)a rocket-propelled guided missile that can escape the earth's atmosphere; makes observations of the solar system that cannot be made by terrestrial observation
The Collaborative International Dictionary of English (GCIDE) v.0.53Collaborative International Dictionary (GCIDE)
n. an unmanned rocket carrying instruments to explore objects or conditions in outer space; -- used mostly for vehicles travelling beyond the earth's gravitational field, rather than in orbital or suborbital flight. [ PJC ]