rootbrowseIAC-19D2session 44. Future Space Transportation SystemsPapers1. Ariane Next, A vision for the next generation of Ariane launchers2. European Next Reusable Ariane (ENTRAIN): A Multidisciplinary Study on a VTVL and a VTHL Booster Stage3. Development status of Japanese reusable experimental vehicle RV-X4. Innovation towards conception - How to design the future generations of space transportation systems.5. Retro Propulsion Assisted Landing Technologies (RETALT): Current Status and Outlook of the EU Funded Project on Reusable Launch Vehicles6. Preliminary Design of Suborbital Spaceplane with LNG Engines by a Japanese University Start-up with the Partnership of Industries7. software-defined launch vehicle8. Powerful & Flexible Future Launchers in 2- or 3-stage Configuration9. Conceptual Design Optimization of Winged Suborbital Vehicles for High-Speed Point-to-Point Transportation10. A Conceptual Design Study for an Unmanned, Reusable Cargo Lunar Lander