First proposed in 2005, the SpaceLiner is under constant development.
Different configurations in terms of propellant combinations, staging, aerodynamic shapes, and structural architectures have been analyzed. A subsequent configuration numbering has been established for all those types investigated in sufficient level of detail. The genealogy of the different SpaceLiner versions is shown in the following figure. The box marks the configuration trade-offs performed in FAST20XX in 2009/10. These configuration studies supported the definition of the next reference configuration SpaceLiner7.
At the end of 2012 with conclusion of FAST20XX, the SpaceLiner 7 reached a consolidated technical status.
Sippel, M., Klevanski, J., Steelant, J.: Comparative Study on Options for High-Speed Intercontinental Passenger Transports: Air-Breathing- vs. Rocket-Propelled, IAC-05-D2.4.09, October 2005
Sippel, M.; Schwanekamp, T.; Trivailo, O.; Lentsch, A.: Progress of SpaceLiner Rocket-Powered High-Speed Concept, IAC-13-D2.4.05, IAC2013, Beijing, September 2013