Posted: Fri, Oct 5, 2001, 12:19 AM ET (0419 GMT)
Investigators now believe that the launch failure of NASA's X-43A experimental vehicle will not be traced to a single root cause. A board of inquiry looking into the June 2 incident said Thursday that they have ruled out most of the 600 possible failure modes and now believe it is unlikely they will find a "single root cause" of the failure. The X-43A, a hypersonic test vehicle, was lost seconds after it and the modified Pegasus launch vehicle it was attached to were dropped from a B-52 flying over the Pacific Ocean off the California coast. The vehicle flew out of control after the apparent loss of one or more control structures, at which point the vehicle was deliberately destroyed. Because the X-43A's booster was derived from Orbital Sciences Corporation's Pegasus booster, that booster has been grounded since the accident, delaying the launch of NASA's HESSI spacecraft until at least mid-November.

Related Links:

•  NASA Dryden press release