This was to a reusable winged rocket-powered atmospheric reentry demonstrator capable of reaching speeds of Mach 4 to 10 in the atmosphere. The aim was for ESA to build up experience in reuse operations and high-speed atmospheric flight in the 2003-2007 period. The demonstrator would weigh two tonnes and have a range of 1500 kilometers. It would be able to land on a conventional runway. Dassault and Aerospatiale Matra were to merge their VEHRA and ARES projects to produce a single design. Ares estimated cost was 550 million dollars.

Themis was a planned ESA booster stage demonstrator, to validate integrated propellant tank technology necessary for a reusable Ariane 5 successor. The demonstrator engine would be derived from the Vulcain of the Ariane 5. Estimated cost was up to 2.5 billion dollars. THEMIS would carry 33 tonnes of propellant, enough to reach Mach 11. Expendable boosters might permit orbital flight.

It was clear from the preliminary study that an immense amount of work needed to be done before even a draft project of a feasible design could be prepared. However this would be accomplished by the mid-1950's. The Keldysh design would lead through the EKR and MKR to the Buran and Burya Mach 3 intercontinental ramjet missiles.

The Tsybin RS was originally a high-speed ground-launched manned aircraft. The March 1954 draft project specified a twin ramjet vehicle that would cruise at 3,000 km/hr at 30 km altitude, over a 14,400 km range, with a takeoff mass of only 22 tonnes. To achieve this performance would require that 75% of the takeoff mass would be structure, and 3% payload, leaving only 22% for the vehicle. This was not achievable, and the final design had an empty weight 43% of the takeoff weight, cutting the range in half. By August 1956 the design had been modified to the more modest RSR configuration, which was air launched, cruised at 2800 km/hour at 26,700 m with a 1700 km radius of action. A subsonic aerodynamic test vehicle, the NM-1 was built and first flown on 7 April 1959 by test p[ilot Amert-Khan Sultan. Construction of prototypes was started the same year, but then stopped in the spring of 1961, with three airframes nearly finished. Tsybin went to work for Korolev at OKB-1.

North American proposed several methods of taking the X-15 spaceplane to higher velocities and altitudes. One of these involved the use of one to three Navaho booster rockets, which could even place the X-15 into orbit. This incremental approach to manned spaceflight was not pursued - the Mercury and X-20 Dynasoar programs were favored instead.

A British Aircraft Corporation study of 1964-1965 for winged reuseable space shuttle using the 'triamese' concept - reduced costs by use of two boosters nearly identical to the orbiter vehicle. The components were lifting bodies with a configuration similar to the US HL-10 vehicle. MUSTARD was an abbreviation for Multi-Unit Space Transport And Recovery Device. The orbiter would be capable of reaching orbit with nearly a full fuel load, since propellant from the two boosters could be pumped into the orbiter prior to separation. This would have allowed the orbiter to reach the moon! Various configurations were examined such as (back-to-back, triangular back-to-back, 2 x back-to back and 1 inline). Developed by a team led by Tom Smith, the MUSTARD vehicles would have been capable of being flown back via remote control or by a pilot.

The Royal Aircraft Establishment Orbital Fighter proposal of the 1960's envisioned a two stage vehicle. A ramjet powered first stage would release a second stage orbiter similar to, but smaller than the U.S. X-20 Dyna-Soar. The spaceplane would utilise a gliding re-entry to return to earth.

• GSR reusable hypersonic air-breathing launch aircraft
• RB expendable two stage rocket
• OS orbital spaceplane

  The project plan for Spiral was as follows:

  • 1967 - Subsonic test flight of OS (article 105-11)
  • 1968 - Hypersonic test flight of OS (article 105-12)
  • 1970 - Unpiloted orbital flight of OS (Soyuz-launched - article 105-13)
  • 1970 - Construction of GSR to begin
  • 1972 - First rollout of LH2-propelled experimental GSR
  • 1977 - First piloted orbital flight of complete system

  Interest in the project at higher levels of the Soviet hierarchy was difficult to maintain, due to the massive funding requirements, technical difficulties, and multi-year development program which could not promise quick results. Underfunded from the beginning, the project was finally reoriented to a simple test of the analogue systems without using these as the basis for a flight system. This was now designated EPOS (Experimental Piloted Orbital Aircraft) and would be flown by Soviet Air Force test pilots rather than cosmonauts. In February 1976, with the beginning of work on Buran, the project was effectively ended except for the test of the subsonic 105-11 article already built. The 105-11 incorporated the airframe and some of the systems of the planned orbital version.

Unique Russian space shuttle design of 1974. Hydrofoil-launched, winged recoverable first and second stages. Hydrofoil would have been propelled to launch speed by the launch vehicles rocket engines, using a 200 tonne fuel store in the hydrofoil. Advantages: launch from the Caspian Sea into a variety of orbital inclinations, variations in launch track possible to meet range safety requirements. Proposal of Alexeyev/Sukhoi OKBs.

The design was found to be feasible but to have little growth potential. Greater payload could only be achieved by the completely different 49M using a new super-heavy carrier aircraft and orbiter. Therefore it was succeeded in the design studies by the 'Bizan' concept.

The 49M was an application of the system 49 design concept, but with a larger carrier aircraft. The system would have a 770 tonne gross takeoff mass. The orbiter/rocket stage combination weighted 370 tonnes, with the orbiter mass being 28 tonnes in orbit, including a 9 tonne payload in a 8.0 m x 3.3 m diameter payload bay. The tripropellant single rocket stage was equipped 1 x NK-43 / 11D112 engine burning Lox/Kerosene and 2 x RD-57 / 11D57 engines burning Lox/LH2. The orbiter could have one or two crew, and was designed for 100 reuses. Development costs for the new heavy lift aircraft and larger orbiter would be too high, and the design was abandoned in favour of the Bizan concept.

The rocket stage was equipped with a single NK-43A / 11D112A engine. The 15 tonne orbiter had two RD-57M / 11D57M engines. The orbiter had a 1000 km cross range and a landing speed of 300 km/hr. One crewmember could stay aloft for mission durations of up to 24 hours. The orbiter was designed for 200 reuses and had a 6.0 m x 2.8 m payload bay. As in the '49' concept, orbits of from 120 to 1000 km altitude and 45 to 94 degrees inclination could be attained.

The HOTOL airframe was derived from conventional vertical takeoff rockets with the engines mounted at the rear of a blunt based fuselage. Since such a vehicle�s empty centre of gravity is dominated by the engine location, the wings and the tank for the dense liquid oxygen also had to be at the rear. The payload bay and hydrogen tankage were placed in a projecting forebody. The resulting configuration suffered from a severe centre of pressure / centre of gravity mismatch during the air breathing ascent. The centre of pressure shifted 10 m forward, due to the wide Mach range, the large fuselage cross section to wing area ratio, and the long overhang of the forward fuselage. Various alterations were made to the design to handle these problems, all of which eroded the payload. Conventional landing gear were replaced by a specially designed takeoff trolley in order to improve the marginal payload fraction. The final design had serious operational disadvantages and a small payload. The only way the designers could continue to claim to put a reasonable payload into orbit was by specifying untried and speculative structural materials.

Proposed two stage to orbit vehicle. Air-breathing hypersonic first stage and delta wing second stage. The German Hypersonics Programme and its Saenger II reference vehicle received most of the domestic funding for spaceplane development in the late 1980s and early 1990s. Saenger II comprised a large hypersonic booster aircraft capable of Mach 4 cruise plus a small rocket-powered upper stage (HORUS) that could deliver people and cargo to low Earth orbit. The booster aircraft (to be powered by turboramjets) was designed for maximum commonality with a supersonic passenger transport (with. a cruise range of 11,000km). Development would have been very costly and the programme was cancelled in 1994.

The 301 was designed as a military bomber, with a Mach 4 / 4,250 km/hr cruise capability at 25,000 to 27,000 m altitude. It was equipped with two turboramjets, had a gross takeoff mass of 80 tonnes, of which half was fuel. It may be related to the first stage of the MIGAKS two-stage vehicle.

The Tu-2000 space launcher would have weighted 260 tonnes at lift-off and be capable of Mach 25 (orbital velocity). An 8 to 10 tonne payload would have been delivered to a 200 km orbit. As with the X-30, airbreathing flight to orbit seemed questionable. The 8 turboramjets would have to be supplemented by a scramjet or a rocket engine in order to achieve orbit.

Work was abandoned as the Soviet Union broke up and the Tu-2000 seemed the preferred solution.

In reaction to US X-30 project, government decrees of 27 January and 19 July 1986 ordered development of a Soviet equivalent. The Ministry of Defence issued technical specifications on 1 September for an MVKS, a single-stage reusable aerospaceplane system. The MKVS was to provide effective and economic delivery to near-earth orbit; develop the technology for effective transatmospheric flight; provide super high-speed intercontinental transport, and fulfil military objectives in and from space. It is known that the Tupolev, Yakovlev, and Energia design bureaux submitted designs. No details of the Yakovlev design have become available to date.

Vertical takoff/horizontal landing two stage launch vehicle study from the 1980s. A larger Earl 14 configuration was studied, but the study centered on the Earl 5 / 18 / 7 configurations. The second stage was mounted on top of the booster. Earl 5 and 7 had winged second stages, with payloads to low earth orbit of 5380 kg to 7180 kg. Earl 14 featured an expendable upper stage which increased payload to 18,000 kg.

The MAKS spaceplane was the ultimate development of the air-launched spaceplane studies conducted by NPO Molniya. The draft project for MAKS was completed in 1988 and consisted of 220 volumes, generated by NPO Molniya and 70 sub-contractors and government institutes. Development of MAKS was authorised but cancelled in 1991. At the time of the cancellation, mock-ups of both the MAKS orbiter and the external tank had been finished. A 9,000 kgf experimental engine with 19 injectors was tested. There were 50 test burns proving the separate modes and a smooth switch between them. Since it was expected that MAKS could reduce the cost of transport to earth orbit by a factor of ten, it was hoped in the 1990's that development funding could be found. However this did not materialise. MAKS was to have flown by 1998.

Fully reusable unpiloted verion of MAKS, similar to Interim HOTOL. Air launched from An-225. MAKS was found to have superior payload, lower non-recurring cost and technical risk. MAKS-M would require new materials. Release conditions: Piggy-back, 275,000 kg, 38.0 m length x 24.0 m wingspan, 900 kph at 9,500 m altitude. Effective velocity gain compared to vertical launch 270 m/s. Payload bay 7.0 m long x 4.6 m diameter.

All cargo version of MAKS. Air-launched heavy-lift launcher would use an expendable second stage with a payload container. Release conditions: Piggy-back, 275,000 kg, 38.0 m length x 24.0 m wingspan, 900 kph at 9,500 m altitude. Effective velocity gain compared to vertical launch 270 m/s. Payload bay 13.0 m long x 5.0 m diameter.

Air launched from Kholod Mach 5 mother ship. This was a Mikoyan supersonic cargo aircraft, designed from Spiral 50-50 design. Combined-cycle turbo-ramjet engine. Release conditions: Piggy-back, 200,000 kg, Mach 5 at 25 to 30 km altitude. Effective velocity gain compared to vertical launch 1130 m/s. It was concluded that the extensive development would be required for the combination-cycle engines, resulting in an extended development schedule and high technical risk. The more conservative subsonic-launched MAKS was chosen instead.

Vertical takeoff, ballistic re-entry, single-stage-to-orbit, Lox/Kerosene/LH2 tripropellant rocket engine powered, reusable launch vehicle. 550 tonne and 770 tonne gross lift-off mass versions considered. For the 550 tonne version, dry mass of the launch vehicle would have to be 68,700 kg / 18 percent of the gross, with payload 8,500 kg / 1.5 percent of the growth. Payload would range from 2000 to 10,000 kg depending on the uncertainties in weight growth of the design during development. As in other vertically-launched SSTO designs, this was considered too great a risk, and the air-launched MAKS was selected instead. Velocity loss during ascent estimated at 1665 m/s compared to 1168 m/s for MAKS (payload 3.1% of gross).

Sled launched, delta winged, single-stage-to-orbit, Lox/LH2 launch vehicle. 290 tonne and 550 tonne versions considered. Sltudied in tradeoff studies leading to MAKS. Release conditions: Piggy-back, 290,000 kg, Mach 0.5, zero altitude. Effective velocity gain compared to vertical launch 100 m/s. The wheeled sled would get the vehicle up to a velocity where the wings could provide lift, allowing lower-thrust engines to be used than in a vertical-takeoff design. This saved weight, but velocity losses during lifting flight to orbit almost cancelled the advantage, resulting in the approach being unattractive in comparison to pure vertical-launch or air-launch designs.

Vertical takeoff, delta winged, single-stage-to-orbit, Lox/Kerosene/LH2 tripropellant rocket engine powered vehicle. 550 tonne gross liftoff mass and 1000 tonne versions studied. Analogous to NASA's Shuttle-2 and RKK Energia's VKS. For the 550 tonne version, dry mass of the launch vehicle would have to be 67,700 kg, with payload 7,500 kg / 1.4 percent of the growth. Payload could therefore be zero depending on the uncertainties in weight growth of the design during development. As in other vertically-launched SSTO designs, this was considered too great a risk, and the air-launched MAKS was selected instead. Velocity loss during ascent estimated at 1619 m/s compared to 1168 m/s for MAKS (payload 3.1% of gross).

Under the Future European Space Transportation Investigation Programme (FESTIP) of 1994-1999 French agencies and contractors designed a number of alternative reusable space launchers. This one was a Sled-launched horizontal takeoff / horizontal landing single stage to orbit. Essentially similar to FESTIP FSS-4

Under the Future European Space Transportation Investigation Programme (FESTIP) of 1994-1999 French agencies and contractors designed a number of alternative reusable space launchers. This one was a Horizontal Takeoff / Horizontal Landing Two Stage to Orbit proposal with Mach 3 stage separation. Later evolved into the FESTIP FSS-11,which was merged with FSS-12. Reusable and expendable upper stage options.

Initiated by a British Aerospace team led by Dr Bob Parkinson in 1991, this was a less ambitious, scaled-back version of the original HOTOL. The single-stage to orbit winged launch vehicle using four Russian rocket engines. It was to have been air-launched from a Ukrainian An-225 Mriya (Dream) aircraft. Interim HOTOL would separate from the carrier aircraft at subsonic speeds, and would then pull up for the ascent to orbit. It would return via a gliding re-entry and landing on gear on a conventional runway. Interim HOTOL suffered from the same aerodynamic design challenges as HOTOL and went through many, many design iterations in the quest for a practical design.

Under the Future European Space Transportation Investigation Programme (FESTIP) of 1994-1999 French agencies and contractors designed a number of alternative reusable space launchers. This one was a Horizontal Takeoff / Horizontal Landing Two Stage to Orbit proposal with Mach 4 stage separation. Vehicle consisted of an unpowered 'reusable winged drop tank' and 2-engine expendable Ariane-5 upper stage.

The Bristol Spaceplanes Spacebus was a Two Stage To Orbit (TSTO) Manned Spaceplane, with an airbreathing supersonic / hypersonic, delta winged first stage and a second stage powered by a liquid fuelled rocket engine. It was proposed by David Ashford of Bristol Spaceplanes Ltd. in the 1980`s / 1990's. The 6-crew Concorde-sized Spacecab would serve as a prototype for the larger 50-person Spacebus.

The Bristol Spaceplanes Spacecab was a Two Stage To Orbit (TSTO) Manned Spaceplane, with an airbreathing supersonic / hypersonic, delta winged first stage and a second stage powered by a liquid fuelled rocket engine. It was proposed by David Ashford of Bristol Spaceplanes Ltd. in the 1980`s / 1990's. The Concorde-sized spacecraft would deliver a payload of 6 persons to low Earth orbit. It would serve as a prototype for the larger 50-person Spacebus.

The Bristol Spaceplanes Ascender of the 1990`s was a sub-orbital manned spaceplane concept proposed by David Ashford. The Ascender spaceplane would use a small Viper tubojet engine as well as a main liquid fuel rocket engine. The Ascender would act as a technology demonstrator for the orbiter of the orbital Spacecab concept,.

Winged, first stage of a launch vehicle using aerial refueling and existing engines. Takes off from runway; rendezvous with tanker to load oxidizer; then flies to Mach 12/150 nm to release Star 48V second stage and 450 kg payload. In comparison to Black Horse, uses existing engines and a much more achievable mass fraction by only flying to half orbital speed.

Sled-launched single stage to orbit vehicle with air-breathing propulsion to Mach 5 (subsonic combustion). The sled would accelerate the launch vehicle to Mach 0.8. Propellants wer slush hydrogen and liquid oxygen. The vehicle would have a 3000 km cross-range on re-entry.

NASA failed to attract industry co-investment to develop an X-34 air-launched, reusable, low-technology, low-cost launch vehicle. So the project was scaled back and NASA contracted with Orbital Sciences to build and fly an unmanned technology demonstrator. Objectives were to demonstrate new, efficient vehicle processing and launch operations and evaluate the performance of advanced reusable launch vehicle technologies. The program was to demonstrate a nominal two-week turnaround between flights, and a surge capability of two flights within 24 hours. The single stage vehicle used NASA�s low cost Fastrac engine for liquid oxygen/kerosene propulsion. The vehicle itself used all-composite primary and secondary structure. Its autonomous flight control system was to make automated approach and landings. Flights were planned to speeds of Mach 8 over an 800 km range. The contract with Orbital Sciences covered construction of three flight vehicles and 26 powered and unpowered flights launched from an L-1011.

Semi-reusable vertically launched two-stage-to-orbit vehicle. The flight profile featured a reusable flyback booster launched from a modular launch platform, an expendable second stage with a reusable orbiter that would have landed vertically. Development cost estimated at $13 billion.

In the late 1990's the Russian space industry undertook the Orel programme to evaluate technology for future launch vehicles. The goals included evaluation of possible concepts for a future Russian launcher, reusable launch vehicle key technology research and analysis of "X-vehicle" flight demonstrators for technology validation. One preferred near-term configuration was this semi-reusable vertical takeoff/horizontal landing two stage launch vehicle. It would use a flyback booster, expendable second stage, and a small manned spaceplane. This was preferred to the Orel V3, which was essentially the earlier MMKS/OK-M1 system with a flyback booster, expendable core tank, and small spaceplane with recoverable main engines.

Dassault design for an air-launched experimental reusable launch vehicle. It would be launched from Novespace's Airbus 300 zero-G aircraft. The lifting-body design was loosely based on Dassault's work on the NASA-led X-38 Crew Rescue Vehicle program. VEHRA weighed 6.5 t tonnes and carried 19.5 tonnes of kerosene and oxygen propellant. One Russian 400.5 kN-thrust NK-39 engine would power the vehicle, which would be capable of reaching Mach 14. The 11.5 meter long vehicle also contained a small 1.5 x 1.5 x 5 meter payload bay for an expendable upper stage+250 kg satellite. Like THEMIS, VEHRA would explore hypersonic flight and the operational and cost aspects of reusability.

Thanks to Nicolas Pillet for providing images and information for this entry.

The Kelly Space & Technology Astroliner Space Launch System was a two-stage-to-orbit, towed space launch concept. Towing an aerodynamic vehicle to an altitude of 6,000 m yielded higher system performance due to vacuum engine performance, reduced drag and gravity losses, and aerodynamic lift during flight. After separation from the 747 towing aircraft at 6,000 m and Mach 0.8, the Astroliner would boost itself to 2750 m/s and 110 km altitude before releasing an expendable upper stage (4.2 m diameter x 7.6 m long) and payload (4.85 meter diameter x 7.56 meter long). The upper stage was capable of delivering a 5,000 kg payload into a 185 km 28.5� orbit at a cost per launch of $ 22 million - 40% of the cost of existing launchers.

Pioneer Rocketplane planned in the late 1990's to produce the Pathfinder aerial propellant transfer spaceplane. Pathfinder was a two-seat fighter-bomber-sized aircraft powered by two turbofan engines and one kerosene/oxygen-burning RD-120 rocket engine. The Pathfinder aircraft was designed to take off with its turbofan engines, and climb to approximately 6,000 m where it would rendezvous with a tanker aircraft. The tanker would transfer 59 tonnes of liquid oxygen to the Pathfinder. After disconnecting from the tanker, the spaceplane ignited its rocket engine and climbed to an altitude of 110 km and a speed of Mach 15. Now on a suborbital trajectory outside the atmosphere, Pathfinder would open its payload bay doors, and release the payload with a liquid rocket upper stage. An expendable solid propellant upper stage could deliver a 2100 kg payload to a 300 km 30 degree orbit. Meanwhile Pathfinder would close its payload bay doors and re-enter the atmosphere. After slowing down to subsonic speeds, the turbofan engines would be restarted and the aircraft flown to a landing field. It was estimated that the price per launch could profitably be set as low as $7 million, 3 to 4 times lower than the price using the Taurus expendable launch vehicle.