Spacecab  

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.

Feasibility

Spacecab can be built using existing technology, meaning that Spacecab's development should not be that much more difficult than a high-performance aeroplane.

The development cost and timescale of the prototype of each stage should be comparable with that of the prototype of an advanced aeroplane, and the estimated total cost then works out at around $1 billion. This prototype could be used for early operational flights to orbit, and would be ideal for launching small satellites and ferrying crews and passengers to and from space.

Bristol Spaceplanes Limited completed a feasibility study of Spacecab and Spacecab Demonstrator (Spacecab Demonstrator was superceeded by Ascender) projects for ESA (contract number 10411/93/F/TB) in 1994.