The European Space Agency says it is funding a study to try to establish the business case for a reusable space plane being developed in Britain. A consortium of companies will try to establish the economic viability of the Skylon, a vehicle proposed by the British company Reaction Engines Ltd. The REL space plane would be powered by an air-breathing rocket engine that could enable it to take off from a standard runway, reach orbit, and then return to Earth to land. The 260-foot-long, unmanned craft, weighing about 325 tons, is expected to be capable of lifting about 15 tons of payload to low-Earth orbit. The ESA\'s $1.5 million study, investigating whether a Skylon vehicle could operate in a market for satellite launches from the early 2020s onward, is to be completed by the end of the year. \"At the end of the study we would like to have demonstrated the full business case for an operator, whoever that might be,\" Mark Hempsell, REL\'s future programs director, told the BBC.