The "I" in "Atlas I" can cause confusion, as all previous Atlas rockets were designated using letters, ending with the Atlas H, however subsequent rockets were designated using roman numerals, starting with the Atlas II.
Atlas | Atlas Shrugged | Atlas Mountains | Natacha Atlas | Atlas of Peculiar Galaxies | Atlas (mythology) | Atlas Comics | Club Atlas | Atlas Comics (1950s) | ATLAS | atlas | Agents of Atlas | Tell Atlas | Tele Atlas | Teddy Atlas | SM-65 Atlas | Charles Atlas | Birdman Atlas | Atlas Shrugged: Part I | Atlas Computer Laboratory | Atlas Autocode | Tony Atlas | SM-65F Atlas | Skalnate Pleso Atlas of the Heavens | Omar Atlas | Middle Atlas | Julie Atlas Muz | International Cloud Atlas | Geographers' A–Z Street Atlas | Dresser Atlas |
The trio of rocket engines used in the first stage of the American Atlas I and Atlas II launch vehicles, arranged in a "row", used parallel staging in a similar way: the outer pair of engines existed as a jettisonable pair which would, after they shut down, drop away with the lowermost outer "skirt" structure of the booster, leaving the central "sustainer" engine to complete the first stage's engine burn towards apogee or orbit.