An individual with sufficient inborn talent, Vernon explains, can perfectly balance a starship's endochronicity with relativistic time dilation, so that a ship traveling at relativistic speeds can age at the same rate as the rest of the universe, allowing it to return to its starting point within months, rather than centuries, of its departure. Vernon emphasizes that starship pilots are expected to match endochronicity with relativity exactly: a sixty-second difference between the two is regarded as barely acceptable, and a 120-second difference is considered grounds for dismissal. Vernon also emphasizes that endochronic molecules are unstable, and must be renewed before each trip, so that an endochronic ship that finds itself lost might not have sufficient endochronicity to return to its proper time. A ship that finds itself in the future might be able to re-endochronize itself if the technology still exists; a ship that finds itself in the past will be marooned there.