Credit: © Mark Wade. 3,013 bytes. 183 x 352 pixels.
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| Hyperion SSTO - Hyperion SSTO Launch Vehicle Credit: © Mark Wade. 3,013 bytes. 183 x 352 pixels. |
The concept of a reusable single-stage-to-orbit Vertical Take-Off Vertical Landing (VTOVL) launch vehicle that would reenter and return to its launch site for turnaround and relaunch was first proposed by Philip Bono in the 1960's. The appealing simplicity of the concept has been offset by the technological risk in developing it. The problem with any single-stage-to-orbit concept is that if the empty weight of the final vehicle has been underestimated it will not be able to deliver any payload to orbit, or even reach orbit. Since weight growth of up to 20% is not unknown in aerospace projects, this is a very real threat which has made both NASA and private investors reluctant to invest the billions of dollars it would take to develop a full-scale flight vehicle. Bono's vehicles proposed minimizing weight by using plug nozzle engines. Cooled by residual hydrogen fuel, these would act as a heat shield for re-entry. More conservatively the recent DC-X designs used a conventional forward heat shield for reentry. The concept was not selected by NASA for the X-33 (an even more risky lifting body design was chosen). This was perhaps the last chance for the concept. The more conservative Kistler recoverable reusable ballistic launch vehicle uses two stages, thereby minimizing the risk.
 | Launch Vehicle: OOST. Bono's first design for an expendable single stage to orbit LH2/Lox booster, using conventional engines. |
| Launch Vehicle: OOST ISI. Bono's first design for an expendable single stage to orbit LH2/Lox booster, using Improved Specific Impulse approach: many engines feeding into single large nozzle. |
 | Launch Vehicle: ROOST. Bono's first design for a reusable single stage to orbit LH2/Lox booster, using conventional engines. |
 | Launch Vehicle: ROOST ISI. Bono's first design for a reusable single stage to orbit LH2/Lox booster, using Improved Specific Impulse approach: many engines feeding into single large nozzle. |
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| Launch Vehicle: Hyperion SSTO. Yet another of Philip Bono's single-stage-to-orbit designs of the 1960's, using a plug-nozzle engine for ascent and as a re-entry heat shield. Hyperion would have taken 18,100 kg of payload or 110 passengers to orbit or on 45 minute flights to any point on earth. Hyperion used a sled for launch, which would have seriously hurt its utility. The sled gave a 300 m/s boost to the vehicle before it ascended to orbit. The sled would have 3 km of straight course, followed by 1 km up a mountainside, with a 3 G acceleration. |
 | Launch Vehicle: Ithacus. An adaptation of Phillip Bono's enormous ROMBUS plug-nozzle semi-single-stage-orbit launch vehicle as a 1,200 soldier intercontinental troop transport!! The recoverable vehicle would re-enter, using its actively-cooled plug nozzle as a heat shield. |
 | Launch Vehicle: Pegasus VTOVL. Bono design for semi-single-stage-to-orbit ballistic VTOVL launch vehicle. Drop tanks were shed on the way to orbit. Pegasus could deliver either a Satun V-size payload to LEO or 172 passengers and their luggage the 12,000 km from Vandenberg to Singapore in 39 minutes. |
 | Launch Vehicle: Rombus. Bono original design for ballistic single-stage-to-orbit (not quite - it dropped liquid hydrogen tanks on the way up) heavy lift launch vehicle. The recoverable vehicle would re-enter, using its actively-cooled plug nozzle as a heat shield. |
 | Launch Vehicle: SASSTO. Bono proposal for first step toward VTOVL SSTO vehicle - heavily modified Saturn IVB with plug nozzle engine. |
| Launch Vehicle: MLLV. Boeing study, 1969, for Saturn follow-on. Plug nozzle, single-stage-to-orbit launch vehicle could itself put 1 million pounds payload into orbit. By addition of up to 12 260 inch solid motors up to 3.5 million pounds payload into orbit with a single launch. |
| Launch Vehicle: Shuttle SERV. Chrysler ballistic single stage to orbit alternate shuttle proposal. |
| Launch Vehicle: Beta. Ballistic single-stage-to-orbit vehicle. |
| Launch Vehicle: VTOVL. Vertical Takeoff Vertical Landing. |
| Launch Vehicle: Orel V7 RSSLV-2. Fully reusable vertical takeoff / vertical landing single stage to orbit. Concept abandoned in favor of Orel V6 by 1998 due to engine reliability concerns. Version with Lox/LH2 propellants. |
| Launch Vehicle: Orel V7 RSSLV-3. Fully reusable vertical takeoff / vertical landing single stage to orbit. Concept abandoned in favor of Orel V6 by 1998 due to engine reliability concerns. Tripropellant Lox/Kerosene (RG-1)/LH2 version. |
| Launch Vehicle: DC-I. Verical Takeoff Vertical Landing. |
| Launch Vehicle: DC-X. Test vehicle to study problems of vertical takeoff/ballistic reentry/vertical landing single stage to orbit launch vehicle. |
| Launch Vehicle: DC-Y. Proposed intermediate protoype test vehicle between DC-X and DC-I operational version. |
 | Launch Vehicle: Kankoh Maru. Kawasaki design for single stage to orbit reusable booster. Would carry 50 passengers to orbiting hotels or fast intercontinental flights. |
 | Launch Vehicle: Roton. The Roton� was a piloted commercial space vehicle design intended to provide rapid and routine access to orbit for both its two-person crew and their cargo. The Roton was a fully reusable, single-stage-to-orbit (SSTO) Vertical Take-off and Landing (VTOL) space vehicle designed to transport up to 3200 kg to and from a 300 km / 50 degree inclination earth orbit. The Roton was planned in 1998 to reach commercial service in the year 2000 with a target price per flight of $7 million. The cargo envelope for the vehicle was 3.66 m in diameter and 5.08 m in height. The original Roton design was to use an innovative novel rotary engine harking back to the Aerojet Rotojet design of World War II. Later this was changed to a version of NASA's Fastrac Engine using Kerosene and Liquid Oxygen propellants. Several would be required to provide the necessary thrust at take-off. Roton would have a height of 19.5 m, a diameter of 6.7 m and a maximum gross lift-off weigh of under 180 tonnes. Using the Fastrac engines, Roton would have to have an empty weight under 5 % of its gross takeoff mass - a very challenging figure for an expendable rocket, let alone the additional mass of the crew, rotor system, and thermal protection system. |