Uncrewed test flight of the Mercury program. The launch proceeded normally until about T+20 seconds when the pitch and roll sequence failed to initiate and the vehicle instead just continued flying straight upward, requiring early termination of the flight. April 25, 1961 at 16:15 UTC · Launch Failure Why: Pitch and roll sequence failed to initiate. Atlas LV-3B — National Aeronautics and Space Administration, to Suborbital Space Launch Complex 14, Cape Canaveral SFS, FL, USA Program: Mercury Data: Launch Library 2, The Space Devs. Image via The Space Devs.