The Apollo mission was a series of spaceflight programs conducted by the United States during the 1960s and 1970s. The Apollo program was the third human spaceflight program undertaken by the United States, following the Mercury and Gemini programs. The Apollo program's goal was to land the first humans on the MOON and bring them safely back to Earth. The Apollo destination was the MOON, which is represented by the 4-letter answer MOON in the crossword puzzle.