NASA is working on future versions of its X-43 Hyper-X as it prepares for a mid-May first flight of the hypersonic experimental vehicle.
The US agency is studying an X-43C which could fly in 2006 in support of a third-generation reusable launch vehicle development. This could be followed by an X-43B, which would be used as a propulsion system demonstrator.
Following a successful captive-carry test on 28 April, attached to an Orbital Sciences Pegasus booster under the wing of a NASA Boeing B-52, the first of three X-43As is scheduled for a Mach 7 test flight on 19 May. The X-43A is powered by a liquid-hydrogen-fuelled supersonic-combustion ramjet (scramjet).
The X-43C would be powered to Mach 6 by a hydrocarbon-fuelled scramjet under development by the US Air Force. The vehicle would be 0.6m (2ft) longer than the 3.7m-long X-43A to provide more room for JP8 fuel. The scramjet would have a 200s burn capability, compared with 5-7s for the X-43A.
The X-43B would be 14-15m long demonstration vehicle for rocket- or turbine-based combined-cycle engines. The vehicle would be accelerated to Mach 4 by a rocket or turbine engine, then to Mach 7 by a ramjet/scramjet.
The X-43C is on track to fly in 2006, NASA says, whereas the $600 million X-43B programme is in the early planning stages.
Source: Flight International
