GUY NORRIS / LOS ANGELES
As another X-43A project gets under way, agency reveals details of potential follow-on
NASA has given the X-43A team approval to start planning a second attempt at achieving hypersonic flight, although the booster control system failure that led to the first X-43A's destruction in June last year is not fully understood.
"We're going to take our time to get back to flight and we have a few additional steps to go through," says NASA Marshall Space Flight Center hypersonic flight demonstration leader Vince Rausch. "However, we will probably fly around May or June 2003."
The test will attempt a flight at Mach 7, while a third flight at Mach 10 is still planned for 2004. As with previous tests, the X-43A will be boosted to 95,000ft (29,000m) and Mach 7 by an Orbital Sciences Pegasus rocket. NASA says the second X-43A vehicle is now at Dryden Flight Research Center, California, where it will be integrated with the booster. This will receive hardware and software "fixes" specified by the mishap identification board.
NASA, which is developing the X-43A hypersonic experimental vehicle as part of its hydrogen-powered Hyper-X demonstration programme, has unveiled first details of a potential follow-on, the X-43D.
Unlike the X-43A's uncooled, hydrogen-fuelled, dual-mode scramjet, the outline X-43D would have a cooled liquid-hydrogen-fuelled dual-mode scramjet. It would provide power for 10s and accelerate the vehicle to Mach 15.
New details have also been revealed of two proposed versions of the X-43B, a scaled-up X-43A being studied as a larger vehicle powered by either a rocket-based combined cycle (RBCC) or a turbine-based combined cycle (TBCC) propulsion system. RBCC work is covered by NASA Marshall's Integrated System Test for an Air-breathing Rocket programme, while TBCC work is centred on NASA Glenn Research Center's Revolutionary Turbine Accelerator (RTA) programme.
Both versions are reusable, air-launched and able to accelerate for 10min or from Mach 0.7 to Mach 7. The RBCC-powered X-43B would be 10m long, with large foreplanes augmenting the aft-mounted delta wing.
The TBCC-version retains the delta wing, but does not require foreplanes. It is 12.2m long and powered by up to four 0.4m-diameter RTA turbojets.
Source: Flight International
