X-43A investigation update
Posted: October 5, 2001

Image taken from chase plane shows the rocket's out-of-control track. Photo: NASA-DFRC
The board studying the June 2 loss of the first X-43A mission expects to find more than one factor responsible for the loss, said Robert W. Hughes, the board chairman from NASA's Marshall Space Flight Center (MSFC), Ala. The team has ruled out most of 600 potential elements identified in a fault tree for the mishap. Hughes stated previously that the likelihood of finding a single root cause of the X-43A mishap was becoming less probable.

The X-43A is designed to be the first scramjet-powered vehicle, capable of attaining speeds as high as Mach 10. The X-43A mission, first in a series of three, was lost moments after the X-43A and its launch vehicle were released from the wing of the NASA B-52 carrier aircraft. Following launch vehicle ignition, the combined launch vehicle and X-43A experienced structural failure, deviated from its flight path and was deliberately terminated.

Hughes repeated that the investigation team was working to fully understand the causal relationship among many elements and likened the board's effort to putting together a jigsaw puzzle. "The activities now being worked are to verify that the board has all the pieces, the pieces are the right pieces and that the pieces fit together in the right order to make a complete picture," Hughes said.

The board continues to meet at the NASA Langley Research Center (LaRC) in Hampton, Va. where they relocated from Orbital Sciences Corporation in Chandler, Ariz. on September 10. Hughes said the relocation of the investigation to LaRC allows the board to better support analyses and testing being performed at LaRC, as well as NASA's Goddard Space Flight Center (GSFC), Md., and MSFC where the bulk of the remaining effort is centered. He said work critical to the investigation will continue at the NASA Dryden Flight Research Center (DFRC), Calif., and at Orbital Sciences until the investigation is complete.

"The bulk of the board effort remaining revolves around fully understanding the critical elements of the control system and vehicle aerodynamics," Hughes said. Extensive wind tunnel testing with the vehicle model and functional testing of the launch vehicle control system has begun. Major analytical assessments have been completed and others are in process to provide and assess the collected data. The team has closed all but one branch of the more than 600-element fault tree that was developed to assist in the investigation of the mishap. The remaining branch deals with the launch vehicle control system, aerodynamics and control elements, Hughes said.

The NASA Langley Research Center at Hampton, Va., leads the X-43A program, with flight operations conducted by NASA Dryden. Orbital Sciences Corporation of Chandler, Ariz., provides the launch vehicle. 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, Goddard, Kennedy (Florida), plus all of the contractor elements.