d on the 3rd stage of the Saturn rocket, this would have been a great way to exploit some of the systems developed for the Apollo project. For political reasons SASSTO was not developed; the Saturn rocket was thrown away; and we had to wait until 1993 for the (much less capable) DC-X to demonstrate the first steps of the VTOVL approach.
SASSTO was one of the earliest SSTO concepts to be proposed. It is the ancestor of Beta and Phoenix, which was in turn the inspiration for Roton, Kankoh-Maru and New Shepard. For more on SASSTO and some of the other vehicle designs in the same family, see "History of the Phoenix VTOL SSTO and Recent Developments in Single-Stage Launch Systems".
A technologically advanced 4 passenger SSTO spaceplane design from the company Lonestar Space Access (formerly Dynamica Research), Cosmos Mariner uses conventional jet engines for take-off and landing, thus allowing it to use the existing FAA air traffic control system and make use of existing airport infrastructure, an issue which VTOL rockets have yet to address. The rocket engines are also planned to use jet fuel which is considerably less volatile than liquid hydrogen. Cosmos Mariner requires advanced and as yet undeveloped technologies though not all of them were needed for its X-Prize bid.
A design for a reusable SSTO VTOL by Dietrich Koelle at MBB in the early 1970s (see "Beta, A Single Stage Reusable Ballistic Space Shuttle Concept"). A key study keeping the VTOL lineage alive! BETA 2 was a later version.
One of the key vehicle designs in the lineage of VTOL rockets. Designed primarily by Gary Hudson and produced during the 1980s by Pacific American Launch Systems in a number of versions, including the "E" (excursion) version to carry passengers for the " Project Space Voyage" with the travel company Society Expeditions in 1985. Many of the same team went on to work on ROTON.
Planned by Rotary Rocket Inc, the Roton was to use a centrifugally-pumped rocket motor for launch, and a helicopter rotor for descent. By their own estimate Rotary Rocket needed over $100 million for development, but managed to raise only $30 million, and so ceased trading in 2000.
The photo on the left is of the Roton ATV (Atmospheric Test Vehicle) that was rolled out of its Mojave hangar facility in March 1999. This vehicle made 3 successful piloted test flights, demonstrating the feasibility of the rotor-assisted landing.
In 1984, British Aerospace proposed the HOTOL horizontal takeoff single-stage-to-orbit reusable launcher. The concept featured a new type of airbreathing rocket engine that would have burned compressed air rather than liquid oxygen up to a speed of Mach 5. HOTOL was studied in great detail both by BAe and the ESA Winged Launcher Configuration study.
The concept eventually gave way to Interim HOTOL in the early 1990s, a British/Russian joint proposal which replaced the (technologically risky) airbreathing rocket motor with existing Russian RD-0120 engines. The vehicle would have been launched piggy-back from a Russian Antonov 225 aircraft. Alan Bond, the inventor of HOTOL's airbreathing propulsion system, later refined the concept as SKYLON, above.
The Space Ship Xperimental was a modified version of the Phoenix VTOL rocket, used by Max Hunter to help persuade the US government to fund VTOL research, ultimately leading to the DC-X project. It is described in "Halfway to Anywhere" by G Harry Stine.
This is a design for a 2-stage HTOL launch vehicle produced initially by the company MBB in Germany (see " Sanger: An Advanced Launcher System for Europe"). The first stage would use air-breathing rocket engines (which have not yet been developed) to reach approximately Mach 6, at which the upper stage would separate and use rocket engines to reach orbit. Piloted versions of the upper-stage have been designed to carry 36, 40 and 44 passengers.
The " X-33" was announced by NASA in 1995 as an unpiloted, reusable VTOHL rocket test vehicle. It was expected to fly to speeds reaching Mach 13, with test flights starting in 1999.
The plan was very soon after scale