Atlas II was the last Atlas to use a three engine, "stage-and-a-half" design: two of its three engines were jettisoned during ascent, but its fuel tanks and other structural elements were retained.
Atlas II adalah Atlas terakhir untuk menggunakan mesin tiga, desain "stage-and-a-half": dua tiga mesin yang telah disingkirkan selama pendakian, tetapi tangki bahan bakar dan elemen struktur lainnya tetap dipertahankan.