A ground test computer was an information storage and processing device utilized on board spacecraft in Earth's early years of space exploration.

The NASA probe Voyager 6 was equipped with a ground test computer, as well as an antenna, with which it was able to receive a signal transmitted from Earth, instructing it to transmit the data it had gathered. In the 2270's, when Voyager 6 was discovered at the heart of the V'Ger entity by the crew of the USS Enterprise, First Officer Will Decker keyed the final sequence of the response code into the ground test computer, initiating a chain reaction which allowed him to physically merge with V'Ger. (Star Trek: The Motion Picture)