The board investigating the X-43A mission loss on June 2 is
continuing to meet at the Orbital Sciences Corp. facility in
Chandler, Ariz., where they relocated on June 24. Orbital is where
the Pegasus-derived booster rocket was built. The Pegasus was
attached to the X-43A to provide the boost to a predetermined

The X-43A mission, first in a series of three, was lost moments after
the X-43A and its booster rocket were released from the wing of the
B-52 carrier aircraft. Following booster ignition, the combined
booster and X-43A experienced structural failure, deviated from its
flight path and was deliberately terminated.

Robert W. Hughes, the board chairman from Marshall Space Flight
Center, has said that the likelihood of finding a single root cause
of the mishap is still possible but becoming less probable. Hughes
restated that the investigation team was working to fully understand
the causal relationship and emphasized that the solution might
involve several contributing causes rather than a single cause.

To date, the team has closed approximately 85 percent of the fault
tree of several hundred possible or contributing causes. The
remaining potential causes, most dealing with launch vehicle control,
are being systematically investigated and evaluated.

The X-43A is designed to be the first scramjet-powered
aircraft, capable of attaining speeds as high as Mach 10.

NASA’s Langley Research Center at Hampton, Va., leads the
X-43A program, with flight operations conducted by NASA Dryden Flight
Research Center, Edwards, Calif. Micro Craft, Inc., of Tullahoma,
Tenn., built the 12-foot-long X-43A vehicle. The mishap
investigation team includes representatives from NASA centers
including Dryden, Langley, Marshall (Alabama), Goddard (Maryland),
Kennedy (Florida), plus all of the contractor elements.