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Reaction Engines Ltd

Reaction Engines Ltd (REL) was formed in August 1989 by Alan Bond, John Scott-Scott and Richard Varvill. Originally, these three engineers all worked on the HOTOL concept, which subsequently evolved into a project named SKYLON, and have 85 combined man-years of technical management experience in the high technology aerospace and nuclear industries.

REL was created to design and develop advanced space transportation and propulsion systems. By applying a combination of established physical principles and innovative engineering design, REL intends to develop a range of products which will enable the commercial exploitation of space.

Since 1989 Reaction Engines has devoted its resources to producing a robust technical design for SKYLON and its SABRE engines while formulating a practical strategy to bring them into commercial production. The knowledge of the directors, their experience from the HOTOL studies and the huge advances in computers over the past decade, have made the demanding task of the preliminary design of SKYLON addressable by a small but highly expert team. In the past this would have been the remit of a large design group in a major aerospace company.

The space plane SKYLON, the SABRE Engine and Heat Exchanger technology are the principal foci of the company. SKYLON is an unpiloted, reusable space plane intended to provide inexpensive and reliable access to space. Currently in proof-of-concept phase, the vehicle will take approximately 10 years to develop and will be capable of transporting 12 tonnes of cargo into space. SKYLON will be able to repay its development costs, meet its servicing and operating costs and make profits for its operators whilst being an order of magnitude cheaper to customers than current space transportation systems. REL has also conducted a study on the passenger capabilities of SKYLON. The conclusion was that a trip to orbit in the upright seat, suitable for stays in Zero-G up to 14 days, would initially cost around €350,000 Euros, but would reduce significantly in price with time.

The SABRE Engine is a hybrid air breathing rocket engine. In the past, attempts to design single stage to orbit rockets have been unsuccessful largely due to the weight of oxidiser, such as liquid oxygen. To reduce the quantity of oxidiser that a vehicle is required to carry, one feasible solution is being able to use atmospheric oxygen in the combustion process. The SABRE engine does this, allowing a two mode operation using both an air-breathing and conventional rocket type operation. This is made possible through a synthesis of elements from rocket and gas turbine technology. Operation from zero forward speed on the runway and up to Mach 5.5 in air breathing mode during ascent enables the air density to fall with altitude, which eventually switches the engine to a pure rocket and consequently propels SKYLON to orbital velocity (around Mach 25).

Heat Exchanger Technology at REL is predominantly focused upon the design and manufacture of the pre-coolers required for the SABRE engine. These heat exchangers have a mass of 1250 kg and are designed to transfer about 400 MW of heat at Mach 5. Their lightweight design is able to cope with thermal expansions and withstand the inertial and aerodynamic loads experienced during flight.

The construction of these heat exchangers pushes manufacturing technology in a number of areas such as:

  • The drawing of matrix tubes in heat-resisting nickel based alloys ensuring correct wall thickness and diameter.
  • Brazing heat exchanger tubes to headers.
  • Machining of heat exchanger tubes to give a profiled (non-constant) wall thickness to ensure good heat exchange properties without compromising physical strength.
  • Hole drilling.
  • Tube forming without ovalisation or wall thinning/buckling.
  • The assembly of large heat exchanger modules incorporating thousands of tubes.

A cryogenic wind tunnel facility was alsoconstructed at our laboratories at Culham, Oxfordshire. This facility has been used to develop a frost control system for the 'air pre-cooler' heat exchanger of the SABRE engine. The pre-cooler is designed to cool the engine airflow (about 400kg/s) from intake recovered conditions (up to 1000°C at Mach 5) down to about -140°C prior to compression. At low altitudes atmospheric moisture will clog the matrix with frost within a few seconds unless preventive measures are taken. This facility has been in operation from 2001 to develop the frost control system over the full temperature, humidity and pressure range of the engine. This program is now drawing to a close as it has been successfully completed.

In February, Reaction Engines Ltd was awarded €1m Euros by the European Space Agency (ESA) to undertake a joint public and private multi-million pound development programme. This programme will demonstrate the core technologies for the SABRE air-breathing rocket engine destined to power the SKYLON space plane. Lord Drayson, Minister for Science and Innovation, said:

"This is an example of a British company developing world beating technology with exciting consequences for the future of space. It is fantastic that Reaction Engines, the British National Space Centre and ESA have successfully secured this public-private partnership arrangement and I look forward to seeing how the project progresses."

The demonstration programme has the objective of removing all of the outstanding technical concerns on the SABRE engine. This will pave the way to a full engine development programme as part of the overall development of SKYLON.

Graphic image - SKYLON Spaceplane

SKYLON Spaceplane

Photograph - SABRE Engine Model

SABRE Engine Model

Photograph - 2 Pre-cooler Modules for the Scimitar Engine

2 Pre-cooler Modules for the Scimitar Engine

Photograph - Cryogenic Wind Tunnel

Cryogenic Wind Tunnel

Contact details

Reaction Engines Ltd
Building D5
Culham Science Centre
OX14 3DB

Telephone: 01865 408314

Fax: 01865 408301


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