Charles Tucker I was the father of Charles Tucker II, and the grandfather of Trip and Elizabeth Tucker. (ENT: "First Flight")
In "First Flight", Tucker refers to his grandfather in the past tense, suggesting he was deceased at that point (2143). His father might be Cyrus.
In "Terra Nova", Trip states that his grandfather saw the first transmissions from Terra Nova as a child, sometime around 2078, though it is unknown which grandfather he is talking about. A comment in which Trip similarly referred to a "grandfather" without identifying which one was written into the final draft script of "Home" but was ultimately omitted from that episode. Trip specifically remarked, "When my grandfather turned eighty, he gave up his business. They practically had to drag him from his garage. He repaired antique automobiles...."