Little Joe 5B was an uncrewed launch escape system test of the Mercury spacecraft, conducted as part of the US Mercury program. April 28, 1961 at 14:03 UTC · Launch Successful Little Joe — National Aeronautics and Space Administration, to Suborbital Launch Area 4, Wallops Flight Facility, Virginia, USA Program: Mercury Data: Launch Library 2, The Space Devs. Image via The Space Devs.