"LIttle Joe II was used to test the Apollo launch escape system. Powered by up to 9 rocket motors with a thrust of 860,000 pounds, Joe could boost a spacecraft on a path which duplicated an Apollo-Saturn in-flight emergency. During the in-flight "emergency" the Launch Escape System fired and pulled the Apollo Command Module containing the astronauts safely away from the booster. Between 1963 and 1966, 5 flew from White Sands Missile Range."
Information taken from Little Joe's plaque