Farscape-1 was John Crichton's space module that was originally designed to be able to survive high acceleration from a gravitational slingshot about the Earth. Crichton arrived in the Uncharted Territories via this craft, after accidentally traveling through a wormhole from Earth. Though Farscape-1 was considered relatively primitive by the standards of the other races Crichton encountered, it was somehow able to navigate wormholes where some other, more sophisticated craft, notably Peacekeeper Prowlers, could not without liquefying passengers.
John modified his module extensively using organic parts from Moya so that it could use various alternate fuels. This allowed it to achieve speeds that were not possible before its modification.
The name of the show comes from this craft's name.