59 Seconds on NASA's X-59 : Envelope Expansion ✈️ NASA's X-59 test pilot Nils Larson shares a behind-the-scenes look at what it takes to fly the one-of-a-kind X-plane. In this video, Larson explains the envelope expansion phase of the X-59 program. Envelope expansion is a series of flights at different altitudes and speeds in which the team performs tests and collects data to demonstrate that the aircraft can safely operate in national airspace. As testing continues, NASA is flying the X-59 high