During the early 1940s, German engineer and rocket scientist Eugen Sänger produced the initial designs for a two-stage rocket-aircraft.

[3] Proposed in the backdrop of the Second World War, it was proposed that the envisioned aircraft for military purposes; in concept, this vehicle would have been capable of travelling at speeds of up to 17,000 kilometers per hour, traversing the Atlantic ocean and dropping a one-tonne payload of armaments upon targets on the East Coast of the United States, including New York City.

Saenger was viewed as being a potential passenger airliner, which would have been both larger and faster than the Anglo-French Concorde, as well as for its use for launching payloads into low Earth orbit (LEO).

[6] In June 1985, a formal presentation on the Saenger launch system was made to the European Space Agency (ESA) council.

[11] By this point, the projected time and cost involved in order to fully complete development work was $12 billion over the course of 20 years.

[12] In 1995, the project was discontinued primarily due to concerns of development costs and limited gains in price and performance compared to the existing space launch systems such as the Ariane 5 rocket.

[5] In a space launch configuration, Saenger would have taken off conventionally and ascended up to a ceiling altitude of 100,000 ft and a maximum speed of Mach 6, after which the second stage would have separated and began its independently-powered ascent to orbit.

[14] The first stage of the Saenger launch system was aerodynamically similar to the proposed hypersonic airliner model, and thus shared a level of a commonality in terms of development work.

[2] Another concept RT-8 "Raumtransporter-8", or "Space Transport 8", was to be powered by a steam rocket, which propelled the first and second stages on a 3-km track to a release velocity of 900 km/h.

[13] As envisioned, the vehicle would take off from a runway using ramjet engines and climb to 30 km altitude and reach Mach 7.