Japan and Europe are getting ready for the maiden flight of their new workhorse launch vehicles: H-3 and Ariane 6. While both vehicles are following an expendable design, reusable vertical take-off and vertical landing (VTVL) concepts are successfully tested and operated in the USA. This evolution has shown that reusability can be a solution for further improvement of competitiveness, versatility and sustainability of future launch system. In order to understand the specificities of reusable launch vehicles in terms of design, optimization and operations, and mature the required key technologies, CNES, DLR and JAXA have decided to join their competences in the project CALLISTO (Cooperative Action Leading to Launcher Innovation in Stage Toss - back Operations). The project aims at developing, building and testing a prototype vehicle which shall, without a technological precursor, demonstrate the mastering of flights and operations representative to a reusable launcher stage. Along all project phases, data and knowhow are being gained about design, manufacturing, operations and maintenance solutions, which are essential for the development of future operational vehicles. CALLISTO vehicle is about 13 m high and 1.1 m diameter, propelled by a JAXA LOX/LH2 engine able to reignite in flight and with continuous deep throttling capability. It is equipped with deployable landing legs and aerodynamic control surfaces. It will be operated from the Diamant launch pad at the French Guiana Space Centre and sized for about 10 flights following different mission profiles, opening the flight domain from low altitude test up to domain relevant for operational vehicles. This paper intends to give an overview about the current status of the project and especially the development status of the aerodynamic analyses, of selected products of the vehicle and of the ground segment.
E. et al. (Sat,) studied this question.