The test model on its inaugural flight.
The Ascender Spaceplane (built by Bristol Spaceplanes Limited)
Ascender is designed to:
Win the X-Prize
Carry passengers on space experience flights
Spearhead low-cost access to space
Ascender is designed to be the first sub-orbital aeroplane since the X-15, and the first ever to carry passengers to space. It would start a sub-orbital space tourism business that would build up the credibility needed for full orbital tourism. It is based on a design included in a feasibility study for the European Space Agency. Four leading British aerospace companies took part in this study, Dowty Aerospace Limited, Dunlop Aerospace Limited, Pilkington Aerospace Limited and Ricardo Aerospace Limited. The UK Minister for Space commissioned an independent review of this study that "did not identify any fundamental flaws" in the concept.
Ascender uses proven materials and existing engines. It takes off from an ordinary airfield using its turbofan engine and climbs at subsonic speed to a height of 8 km. The pilot then starts the rocket engine and pulls up into a steep climb. When the rocket fuel is used up Ascender is climbing close to the vertical at a speed of Mach 2.8, from which it coasts to a maximum height of 100 km. Ascender then enters a steep dive. On reaching the atmosphere the pilot pulls out of the dive and flies back to the airfield from which he took off 30 minutes previously.
Ascender will carry a crew of two and two passengers (or other payload) to space and back. Passengers will experience two minutes of weightlessness, will see superb views of Earth, and will see the sky turn black even in daytime.
Ascender uses proven materials and existing engines. The only innovation is in the concept, which is in essence that of a light aeroplane of hypersonic shape fitted with a rocket motor.
Ascender would be the first aeroplane capable of taking off under its own power and of making several flights to space per day. (The X-15 of nearly forty years ago had a somewhat higher performance, but had to be launched from a B-52 converted bomber and needed several weeks of servicing between flights.)
Ascender could be flying in three years as a research aeroplane, and carrying passengers on space experience flights within seven years. Work at present is being funded privately. Discussions are taking place with potential strategic partners. Ascender has EUREKA status as a suggested project.
Ascender is offered for a variety of research purposes, for astronaut training, and for passenger space experience flights.
Feasibility
Ascender is well within the aeronautical state of the art. The aerodynamics, structure, engines and systems are all based on those of existing aeroplanes or launchers. The originality is the way the total concept has been put together so that conventional technology leads to a unique capability.
Ascender Specifications
Span 7.9 m
Length 13.7 m
Maximum Speed Mach 4.5
Maximum Altitude 100 km
Take-Off Weight 4500 kg
Engines 2 x Williams-Rolls FJ44 and One Pratt & Whitney RL 10
Cost and Programme
The development programme calls for Ascender to fly within three years of full go-ahead. The cost to early operational use is comparable to that of just one fighter aeroplane off the production line. This remarkably low cost is made possible by the design concept and by excluding any component not essential for the basic mission.
After a few years in sevice, the cost per flight of Ascender would be reduced to a level comparable to that of a jet fighter, i.e. a few £ thousand. Then routine everyday flights to space (albeit brief) would become possible at a cost affordable by middle income people prepared to save.
Successors
Ascender would lead naturally to a fully orbital spaceplane. That proposed by Bristol Spaceplanes Limited, Spacecab, uses existing engines and proven materials and would be ideal for launching small satellites, for ferrying crews to and from space stations, and for pioneering orbital space tourism.
The cost of developing Spacecab* is equivalent to about three Shuttle flights. The cost per flight will be well over 100 times less than that of the Shuttle, such are the benefits of full reusability. (The Shuttle is only partly reusable. It is like a car whose fuel tank has to be renewed and engine stripped down and refurbished after every journey.) Thus Spacecab would pay for its own development very soon, by greatly reducing the cost of space missions.
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*The Spacecab (By Bristol Spaceplanes)
The Spacecab Concept
Spacecab is a fully reusable spaceplane designed to use only existing technology. It is in effect an enlarged and refined Ascender, air launched from a carrier aeroplane like a much simplified Concorde. It could start passenger operations much earlier than a vehicle requiring new engines to be developed whilst providing a low-risk stepping-stone to the development of a mature spaceplane such as Spacebus.
The original aspects of Spacecab are that its most basic design features have been selected so that existing technology can be used and so that it has provision for certification to airliner standards. It therefore incorporates as many conventional airliner design features as practicable, such as carrying pilots and taking off and landing horizontally (Landing vertically using rocket lift, as has been proposed by some, would present severe certification difficulties because there are so many critical failure modes).
Key Design Features
Conservative design
Fully reusable
Booster with jet and rocket engines
Separation at very high altitude
Buried orbiter
Spacecab Design
Spacecab comprises two stages: a booster and an orbiter. The orbiter is partly buried in the booster to protect it from air loads during the boost phase of the flight to Mach 4 and to reduce the drag at supersonic speeds.
In order to use existing engines and proven materials, and to have the margins required for civil certification, the booster has four turbojet engines provide the power for take-off, acceleration to Mach 2, flyback and landing plus two rocket engines to accelerate Spacecab from Mach 2 to Mach 4, at which the orbiter will separate.
The orbiter carries a crew of two and has a cabin with a capacity for six passengers or space station crew or a payload of upto 750 kg of cargo. Its blunt swept-back shape reflects the fact that streamlining is not required for flight in space but reduces heating during reentry into the atmosphere.
bristolspaceplanes.com