NASA and Orbital Sciences plan to begin captive-carry flight tests of the X-34 reusable launch vehicle (RLV) technology demonstrator on 18 June, marking the start of an ambitious programme aimed at achieving the first of 27 powered test flights in January next year.
The captive-carry flights, using the Virginia-based Lockheed L-1011 as the mothership, are expected to be made from NASA's Dryden Flight Research Center at Edwards AFB, California.
Orbital Sciences hopes that "less than 10" captive-carry flights will be needed before the US Federal Aviation Administration clears the L-1011/X-34 combination for unpowered drop tests, scheduled for August or September.
For this phase, the 17.7m (58ft)-long vehicle will be dropped from the L-1011 at around 25,000ft and will glide autonomously to land at Edwards.
A second X-34 airframe - the A2 - will be used for the drop tests, while the airframe rolled out at a ceremony at Dryden last month will be available for possible conversion to free flight status at a later stage, says Orbital.
A third vehicle - the A3 - is also under construction and is scheduled to be used for flight tests and for tests of advanced systems, materials and control software.
The testbed role of the A3 is an extension of the X-34's primary purpose as a technology demonstrator for NASA's RLV programme. The X-34 is an unmanned hypersonic vehicle powered by a 60,000lb (267kN)-thrust "Fastrac" rocket engine. Initial problems with the liquid-oxygen/kerosene engine, being developed by NASA's Marshall Space Flight Center, have largely been overcome and the first of up to 85 full-power "hot" test firings was achieved in March.
Problems with the engine, and with some composite structure manufacturing processes, have delayed the scheduled first X-34 flight date by up to a year.
Source: Flight International
