Star Trek: Enterprise: Season 2, Episode 24

2 - 24: First Flight

Stunned by the death of former Starfleet rival and friend, A.G. Robinson, in a mountain climbing accident, Archer grudgingly recalls their competitive relationship with T'Pol as they probe a possible dark matter nebula during a shuttle voyage. He describes how he and A.G. broke the Warp 2.5 barrier on the first high-warp test flight that saved the NX program almost ten years earlier. After they confirm the first dark matter nebula, T'Pol suggests Archer name it the Robinson Nebula.