Little Joe II was an American rocket used from 1963–66 for five unmanned tests of the Apollo spacecraft Launch Escape System (LES), and to verify the performance of the Command Module parachute recovery system in abort mode. Named after a similar rocket designed for the same function in Project Mercury, Little Joe II was a single-stage, solid-fuel rocket which used a booster engine developed for the Recruit rocket, and a sustainer engine developed for the Algol stage of the Scout rocket family.