Jack Crichton is the father of John Crichton on Farscape. Introduced in "the premiere, Jack Crichton is a retired NASA astronaut and proud father. Periodically, across all four seasons of the series, the senior Crichton would re-appear, often as a false image, and is representative of John's desire to return to Earth and family. The two Crichtons often went fishing, and to determine whether "Jack" is real, in multiple episodes, John asks, "Was it a bass, or a trout?"
In the fourth season, John was finally re-united with his real father, first in the past in "Kansas," where the elder John must correct a time-line anamoly by having his younger self keep Jack from boarding the Challenger.In "Terra Firma," John returns in the present day, only to find his dad has become nationalistic and isolationist. As Project Director for Extraterrestrial Studies for IASA (International Aeronautics and Space Agency), Jack is now a "suit," and some friction arises between father and son about how both have "changed." This is resolved by episode's end, however, with an emotional departure.
The final encounter between Jack and John occurred in "Bad Timing," the final episode of the original series. Aware that the Scarrans are planning to attack Earth, John decides to collapse the wormhole linking Earth to the outside galaxies. After landing a transport pod on the Moon, John is able to communicate with his father's house, and the two exchange their final goodbyes before the line is closed.