CALLISTO (Cooperative Action Leading to Launcher Innovation in Stage Toss-back Operations) is a single stage and reusable VTVL demonstrator[1] propelled by rocket engine and developed jointly by the German Aerospace Center, the French Space Agency, and the Japanese Aerospace Exploration Agency. The goals are to mature and demonstrate the technologies[2] which are necessary to build and operate a reusable launch vehicle, but also to better assess the operational cost of such a vehicle. The first flight is planned for 2022.


  1. ^ Dumont, E; Ecker, T; Chavagnac, C; Witte, L; Windelberg, J; Klevanski, J; Giagkozoglou, S (2018), "CALLISTO - Reusable VTVL launcher first stage demonstrator" (PDF), Space Propulsion Conference 2018, Sevilla, Spain.
  2. ^ Dumont, E; Ishimoto, S; Tatiossian, P (June 2019), "CALLISTO: a Demonstrator for Reusable Launcher Key Technologies", 32nd ISTS, Fukui, Japan.