UK-based Reaction Engines will conduct additional tests on an advanced rocket nozzle design for use in its Skylon spaceplane, FlightGlobal.com reports. The company is testing an expansion-deflection (ED) nozzle, which is designed to compensate for changing atmospheric pressure at different altitudes to deliver superior engine performance. Reaction Engines plans to use ED nozzles in its Sabre engine, which will power its horizontal take-off, horizontal landing Skylon orbital spaceplane.