The Long-Term Advanced Propulsion Concepts and Technologies ( LAPCAT ) is a program of the European Space Research and Technology Centre ( ESTEC ), an agency of the European Space Agency (ESA). The objective is the development of a hydrogen engine, to reach speeds of about 6000 km / h ( Mach 5 ) with the civilian aircraft.

The right to the engine aircraft with delta wings, which will have approximately 140 meters in length (compared to an Airbus A380 is about 72 m, the Concorde approximately 62 m long), is designed under the project name A2.

Engines are to be developed for the successor of the supersonic passenger jet Concorde, which could not only achieve supersonic, but hypersonic. Such a plane with 300 passengers and a total load of 400 tons could the route Brussels - cover Sydney in four hours.

Since conventional turbofans (English turbofan ) at 3000 km / h its maximum limit, only a ramjet (English Ramjet ) comes into question. Since ramjets only from several 100 km / h speed function, the engine must also have a turbo function to reach this speed first. It is thus necessary a combined engine. Such a combination engine comprises, for example, the Lockheed SR- 71 with the Pratt & Whitney J58 on.

Since even ramjets from Mach 5 develop overheating problems, this engine (English scramjet ) must be run as a ramjet with supersonic combustion, in which case cryogenic temperature systems must be developed to cool the incoming air.

Such a system was used in the American unmanned X -43A prototype of NASA, in November 2004, the currently valid record of Mach 9.6 ie 11,250 km / h achieved with this aircraft.

The flights must take place at an altitude of 20-30 km, where the air is thin enough, but still ready enough oxygen for combustion.

ESA coordinator of the 14 partners from 6 EU countries Belgium, Germany, France, Italy, the Netherlands and the UK is Johan Steelant.