This is a list of upper stages used on rockets.

Name Country Flown on Proposed for Status Remarks Agena United States Atlas, Thor, Thorad, Titan IIIB Retired Block D Soviet Union Russia N1, Proton, Proton-K Retired Block DM Soviet Union Russia Proton-K, Proton-M In service Block DM-SL Soviet Union Russia Zenit In service Briz-KM Russia Rokot In service Briz-M Russia Proton-K Proton-KM Proton-M In service Centaur United States Atlas, Atlas G, Atlas I, Atlas II, Atlas III, Atlas V, Titan IIIE, Titan IV Blue Streak, Saturn I, Space Shuttle In service Earth Departure Stage United States Ares V In development Fregat Russia Soyuz-U, Soyuz-FG, Soyuz-2 Zenit In service Inertial Upper Stage United States Titan 34D, Titan IV Retired Payload Assist Module/Star-48B United States Delta 3000, Delta 4000, Delta II, Space Shuttle Delta 5000 In service Transtage United States Titan IIIA, Titan IIIC, Titan 34D Retired This list is incomplete; you can help by expanding it.